The simulation-lucid phenotype: aphantasia as a window into ancient cognition and psychedelic mechanisms¶
Individuals with complete aphantasia who retain full interoceptive-proprioceptive processing represent an untapped natural experiment for consciousness research. The absence of cortical sensory simulation in these individuals—estimated at ~1% of the population—does not produce cognitive impairment. Instead, it makes visible the interoceptive-somatic cognitive system that operates in every mammalian brain but is normally obscured by the cortical "rendering engine" layered on top of it—much as albinism reveals the melanin synthesis pathway that exists in all skin by removing the pigmentation that normally makes it invisible. This phenotype, here termed "simulation-lucid," has no existing equivalent in the literature but draws on converging evidence from aphantasia neuroscience, predictive processing, interoceptive cognition, and psychedelic pharmacology. The term draws an analogy to lucid dreaming: most individuals are simulation-immersed — running the cortical imagery overlay and experiencing its outputs as the default texture of cognition, with the interoceptive substrate obscured in conscious report by the rendering that covers it. Simulation-lucid individuals, by constitutional absence of the overlay, have unmediated access to the substrate — not because they have achieved some special insight, but because the rendering that would normally dress up substrate-level processing was never present. (We acknowledge that "simulation-lucid" is an imperfect coinage — it risks being parsed as "having lucid simulations," the opposite of its intended meaning. If a more precise term emerges from the research community this framework is meant to serve, we would welcome the improvement. The conceptual distinction it marks — between immersion in the overlay and transparency to the substrate — is more important than the label.) Including aphantasic participants as essential collaborators in psychedelic and consciousness research would allow researchers, for the first time, to dissociate visual hallucinatory artifacts from the actual therapeutic mechanisms of these compounds. The implications extend to animal cognition, meditation science, IQ measurement, clinical practice, and our fundamental understanding of what consciousness requires.
Part I — The cortical simulation engine and what its absence reveals¶
How prefrontal cortex commandeers sensory cortices to generate inner experience¶
Mental imagery operates as "perception in reverse." When the prefrontal cortex generates an internal visual scene, it drives top-down activation through the cortical hierarchy—from higher-order association areas down through extrastriate cortex and, in many cases, into primary visual cortex (V1/V2). Dijkstra et al. (2017) demonstrated through dynamic causal modeling that top-down coupling from frontal to early visual areas increases during imagery far more than during perception, and that experienced imagery vividness correlates selectively with the strength of this top-down connectivity. Keogh, Bergmann, and Pearson (2020) established a causal mechanism: the ratio of V1 to superior frontal activity predicts imagery strength, with electrically decreasing visual cortex excitability via tDCS actually increasing imagery vividness. The "chalkboard" metaphor applies—a quieter visual cortex receives a cleaner top-down signal.
Joel Pearson's comprehensive review in Nature Reviews Neuroscience (2019) synthesized this as a network stretching from frontal cortex to sensory areas, substantially overlapping with the default mode network, functioning as a "weak version of afferent perception." Koenig-Robert and Pearson (2019) decoded imagery content from fMRI activity as far as 11 seconds before the voluntary decision to imagine, demonstrating that sensory-like neural representations emerge spontaneously before volition. Their modulation-versus-excitation framework (2021) provides the crucial mechanistic distinction: whereas perception-related feedforward connections are "driving" (increasing spiking rates), imagery-related feedback signals are "modulatory" (suppressing neural activity coding for non-relevant processing). This explains why imagery feels phenomenologically different from perception—it sculpts existing activity rather than generating new activation.
A meta-analysis by Winlove et al. (2018) of 634 foci from 464 participants confirmed V1 activation during visual imagery even with eyes closed, alongside reliable engagement of superior parietal lobule, inferior premotor areas, and frontal eye fields. The picture is of an extensive cortical-to-cortical simulation system that borrows the brain's sensory processing hardware for internally generated content. This system is what aphantasia lacks—but it is an overlay, not the whole system. Beneath it, a more ancient processing substrate continues to operate.
What aphantasia teaches us about simulation's neural architecture¶
Adam Zeman's foundational work—from the original case of patient "MX" (2010), a surveyor who lost imagery after coronary angioplasty, through coining the term "aphantasia" in 2015, to his comprehensive 2024 review in Trends in Cognitive Sciences—has established aphantasia as a robust neurological variant. Current prevalence estimates converge on ~1% for complete aphantasia (VVIQ score of 16) and ~3–4% for significant imagery weakness, with no gender bias. Aphantasia runs in families, often affects imagery across multiple sensory modalities, and is associated with reduced autobiographical memory, impaired face recognition, and a tendency toward scientific occupations.
The critical neuroimaging evidence comes from multiple converging lines. Milton et al. (2021) used resting-state fMRI to demonstrate reduced functional connectivity between prefrontal regions and the visual-occipital network in aphantasia compared to hyperphantasia. Liu and Bartolomeo (2023), using ultra-high-field 7T fMRI, identified a "Fusiform Imagery Node" (FIN) that activates during imagery in typical imagers but shows reduced functional connectivity to frontoparietal areas in aphantasics. Zeman's 2024 review proposes five candidate neural variations underlying aphantasia: (1) weakened top-down feedback connections between frontal and visual cortex, (2) altered frontal cortex structure or function, (3) differences in higher-order visual areas including FIN, (4) V1 anatomical variation, and (5) altered parietal components of the frontoparietal control system.
The most consequential recent finding comes from Chang et al. (2025) in Current Biology. In a study of 14 aphantasic participants and 18 controls, they found that when aphantasics attempt to imagine, their primary visual cortex is activated and distinct neural patterns are generated—algorithms could decode what aphantasics were attempting to imagine from brain activity in V1. However, these patterns are fundamentally different from perception patterns and cannot be cross-decoded with perceptual representations. Pearson described this as the brain "doing the math but skipping the final step of showing the result on a screen." This "imageless imagery" finding has generated productive debate: Scholz, Monzel, and Liu (2025) argued in a Current Biology response that these representations should not be characterized as "unconscious imagery" because they fail to show the perception-like patterns normally associated with mental imagery. Chang et al. (2025) replied that they do not claim unconscious imagery, but that the representations are "perceptual-like but transformed." This exchange clarifies rather than undermines the finding's significance: computational processing occurs in V1, but it does not produce conscious sensory experience—supporting the three-stage model of generation, integration, and amplification where aphantasia reflects preserved generation with impaired conscious rendering.
The gating-versus-generation debate—whether imagery is generated but not consciously accessible or simply not generated—now appears to be resolving into a more nuanced three-stage model. Liu (2025/2026) proposes that imagery requires (1) generation of initial sensory reactivations, (2) integration binding visual features into coherent perceptual-like content, and (3) amplification enhancing them for conscious access. Aphantasia primarily reflects deficits in top-down modulation during integration and amplification, with preserved generation but impaired conscious rendering. This is supported by the behavioral evidence: binocular rivalry paradigms show no imagery priming in aphantasics (Keogh and Pearson, 2018, 2024), pupillary light responses are absent during imagery attempts (Kay et al., 2022), and fear-based skin conductance responses are reduced (Wicken et al., 2021)—all consistent with functionally absent sensory simulation despite some residual subcortical computation.
Multi-sensory aphantasia and anauralia—coined by Hinwar and Lambert (2021) for absence of auditory imagery—demonstrate that this deficit can extend across modalities. Dawes, Keogh, and Pearson (2024) identified distinct subtypes through cluster analysis: visual-only aphantasia and multi-sensory aphantasia affecting all modalities. Approximately 54% of visual aphantasics also report deficits across all imagery types. This suggests that for a substantial subpopulation, the entire cortical simulation overlay—not just the visual component—is functionally absent. These are the individuals who most clearly make visible the interoceptive-somatic processing that operates in every brain but is normally obscured by the simulation overlay—just as the absence of pigmentation reveals skin structures visible in all tissue but normally hidden beneath melanin.
The overlay is a ventral stream phenomenon — the substrate includes the dorsal stream¶
The overlay/substrate distinction maps onto the well-established ventral/dorsal stream architecture first described by Farah, Hammond, Levine, and Calvanio (1988, Cognitive Psychology). The ventral "what" stream processes object appearance — color, texture, form — while the dorsal "where" stream handles spatial relations, transformations, and locations. Aphantasia primarily disrupts the ventral stream while leaving dorsal spatial processing substantially intact. Bainbridge, Pounder, Eardley, and Baker (2021, Cortex) demonstrated a striking double dissociation: aphantasics drew significantly fewer objects and less color from memory (impaired object/ventral processing) but placed objects at correct locations with correct relative sizes at rates equivalent to controls (preserved spatial/dorsal processing). On the Object-Spatial Imagery Questionnaire, aphantasics score far below controls on the Object subscale but show no significant difference on the Spatial subscale (Keogh & Pearson, 2018; Dawes et al., 2020). Reeder et al. (2024, Cognition) found that aphantasics overwhelmingly prefer non-visual spatial and sensorimotor strategies over verbal ones, with performance indistinguishable from controls using visual strategies. As Phillips argued in a 2025 Trends in Cognitive Sciences commentary, spared spatial imagery is the solution to the "aphantasia puzzle" — the question of how aphantasics perform normally on tasks presumed to require imagery.
This ventral/dorsal mapping provides anatomical specificity for the overlay/substrate model. The overlay is fundamentally a ventral stream phenomenon — the rendering of object appearances, scenes, and sensory detail through top-down activation of visual cortex. The substrate includes dorsal spatial processing alongside the interoceptive hierarchy (Craig) and subcortical emotional systems (Panksepp) — architecturally distinct systems that are not impaired when the ventral overlay is absent. This is why removing the overlay does not produce cognitive impairment: the substrate is not a degraded version of the overlay but a separate system running through different anatomy. Chang et al.'s (2025) finding that the brain "does the math but skips showing the result on a screen" is the ventral/dorsal dissociation in action — the dorsal computation proceeds; the ventral rendering does not.
The Yeung et al. (2025) finding that vivid object imagery (ventral/overlay) is a PTSD risk factor while spatial imagery (dorsal/substrate) is protective becomes more interpretable through this mapping. The overlay is the vulnerability — the rendering engine that replays trauma. The substrate includes a dorsal spatial system that may help recontextualize traumatic memories through spatial-schematic processing rather than reliving them through sensory detail. This suggests that the overlay/substrate distinction is not merely descriptive but clinically consequential: identifying which stream a patient's processing runs through has direct implications for therapeutic approach.
Part II — The interoceptive substrate: what every brain runs on¶
Bud Craig's interoceptive hierarchy and the anterior insula as seat of feeling¶
The interoceptive system is not an alternative to the cortical simulation engine. It is the substrate on which the simulation engine was built—and it continues operating in every brain, whether or not imagery is present. In typical imagers, interoception is always running: the "gut feeling" about a decision, the bodily sense that something is wrong in a social interaction, the somatic shift that accompanies insight. These experiences are not metaphors. They are interoceptive events processed through the same neuroanatomical hierarchy that aphantasia makes visible by removing the rendering overlay that normally dominates conscious report. The interoceptive system described by A.D. (Bud) Craig provides the most detailed neuroanatomical account. Craig's foundational work (2002, 2003, 2009) established that primates possess a distinct cortical representation of homeostatic afferent activity reflecting the condition of all body tissues. Lamina I neurons in the spinal cord organize as distinct sensory channels for pain, temperature, itch, muscle sensations, and visceral states. These project via the lateral spinothalamic tract to the posterior ventral medial nucleus (VMpo) of the thalamus, then to the dorsal posterior insula—primary interoceptive cortex.
Craig's model describes a progressive integration hierarchy: posterior insula (primary interoceptive representation) → mid-insula (multimodal integration with exteroceptive, motivational, and hedonic inputs) → anterior insular cortex (AIC), which generates a meta-representation of integrated body state that Craig proposes as the neural correlate of subjective awareness itself. The AIC is implicated in an extraordinary range of conditions: bowel distension, orgasm, decision-making, maternal love, and sudden insight—all cases where awareness of "how I feel right now" is central. The AIC contains von Economo neurons (VENs), large spindle-shaped cells proposed to relay rapid intuitive assessments in complex social situations. VENs are found in humans, great apes, cetaceans, and elephants—precisely the species exhibiting the most complex social cognition—suggesting convergent evolutionary solutions for rapid interoceptive social processing.
Silvanto and Nagai (2025a) have directly connected this system to aphantasia, proposing that the insula regulates the gain of top-down predictions from prefrontal cortex, and that impaired interoceptive precision leads to reduced confidence in mental acts, preventing imagery from reaching consciousness. In a second paper (Silvanto & Nagai, 2025b), they formalize this as a predictive coding account in which two components are affected: agency (the capacity for voluntary control over mental content) and embodiment (the sense that mental content belongs to the self, arising from integration of internal bodily states with sensory information). When interoceptive precision is low, the insula downregulates gain on prefrontal predictions, preventing imagery from activating sensory cortex sufficiently for conscious experience. This model generates a crucial prediction: interoceptive processing profiles may vary across aphantasia subtypes.
Converging empirical evidence now supports this. Data from Nagai et al. (2025), studying 468 participants, found that aphantasics report significantly lower subjective interoceptive awareness. Most strikingly, Monzel et al. (2025) demonstrated through structural equation modeling that the relationship between imagery vividness and mental health is mediated by alexithymia and subjective interoceptive processing. Their finding that core aphantasics (VVIQ = 16) showed better mental health than hypophantasics (VVIQ 17–32) — with the opposite pattern from typical imagers, where more vivid imagery predicts better outcomes — suggests that partial overlay disruption may be worse than complete absence. Hypophantasics showed effortful but unsuccessful interoceptive processing (low accuracy-to-attention ratios), while core aphantasics appeared to have adapted to substrate-level processing. This is consistent with the unity framing: the substrate operates in all brains, but when the overlay is completely absent, individuals may develop more effective direct access to the substrate than those with a degraded but still-interfering overlay.
Somatic markers: the body's evaluation system operating in every brain¶
Antonio Damasio's somatic marker hypothesis (1991, 1994, 1996) provides the decision-making framework. The ventromedial prefrontal cortex (VMPFC) and insula generate body-state simulations—"somatic markers"—that bias decision-making through both conscious ("gut feelings") and unconscious ("as-if loop") pathways. The Iowa Gambling Task experiments by Bechara et al. (1997) demonstrated the most striking evidence: healthy participants generated anticipatory skin conductance responses before selecting from disadvantageous card decks, differentiating bad from good options before they could articulate any conscious knowledge. The body "knew" before the mind. VMPFC patients never developed these anticipatory signals and continued making poor decisions.
These somatic markers operate in every brain that has an intact VMPFC-insula circuit—which is to say, in typical imagers as well as aphantasics. The difference is not in the presence or absence of somatic evaluation but in its visibility. In typical imagers, body-based evaluation signals are frequently overwritten in conscious report by the imagery overlay: the person says "I imagined the scenario and it felt wrong" when what actually happened was that the somatic marker fired, the imagery system then rendered a scenario post-hoc, and the conscious report attributed the evaluation to the image rather than to the body signal that preceded it. In aphantasia, there is no overlay to attribute the signal to. The somatic marker is experienced as what it is—a body-based evaluation signal. This does not make aphantasic decision-making fundamentally different in kind from typical decision-making. It makes it more transparent about the mechanism that all decision-making shares.
The "as-if loop" is particularly relevant. In this pathway, the brain generates body-state predictions in somatosensory cortex without requiring peripheral bodily changes or conscious sensory simulation. This system provides evaluation and confirmation signals in every brain. In typical imagers, these signals are woven into the imagery experience and difficult to isolate. In aphantasia, they stand alone—visible, reportable, and available for study.
Empirical support for this visibility distinction comes from Monzel, Karneboge, and Reuter (2024), who demonstrated that aphantasics show reduced emotional responses specifically to verbal stimuli — which require imagery to amplify — while responding comparably to controls when emotional information arrives through direct visual perception. The study also identified a higher prevalence of alexithymic symptoms (difficulty identifying and describing feelings) in aphantasia, with imagery vividness mediating the association between alexithymia and sympathy. Critically, aphantasics recognized emotions in others with equivalent accuracy but slower response times, suggesting alternative non-imagery strategies for affective processing. This pattern is precisely what the substrate/overlay model predicts: when emotional information must pass through the imagery overlay to reach conscious report, aphantasics show reduced response; when it arrives through direct perceptual or interoceptive channels, processing is intact.
Subcortical emotional systems: the deeper universality¶
Jaak Panksepp's affective neuroscience program (1998, 2010) provides the evolutionary grounding. His identification of seven primary-process emotional systems—SEEKING, RAGE, FEAR, LUST, CARE, PANIC/GRIEF, and PLAY—all organized within subcortical circuits that are anatomically, neurochemically, and functionally homologous across all mammals, demonstrates that emotional experience does not require neocortical simulation. Electrical brain stimulation producing coherent emotional behaviors is concentrated exclusively in subcortical regions; no dramatic, unambiguous emotional behaviors have been elicited from neocortical stimulation. During intense emotional episodes, significant reductions in blood flow were observed in many neocortical regions—cortical processing actually diminishes during intense emotion.
Merker (2007) extended this argument dramatically by documenting hydranencephalic children—born without most cerebral cortex—who were alert, responsive, expressed emotions through smiling and crying, recognized familiar adults, showed preferences for specific toys and tunes, and displayed situationally appropriate behavior. While the degree of consciousness in these children is debated, the evidence challenges the equation of cortex with awareness. Shewmon, Holmes, and Byrne (1999) documented four congenitally decorticate children (ages 5–17) showing consciousness despite total or near-total absence of cerebral cortex.
Cross-species evidence strengthens this picture. Ben-Ami Bartal et al. (2011) demonstrated that rats intentionally and consistently opened restrainers to free trapped cagemates, even sharing chocolate when liberation competed with food access. Using fiber photometry (2021), they found that all rats experience empathy-network activation in response to distressed peers, but reward circuitry activates selectively for in-group members. Elephant grief behaviors include temporal gland streaming (emotional arousal), sustained vocalizations, attempts to lift deceased individuals, and—documented in 2024—positioning dead calves into trenches and covering them with earth. Cetaceans achieve complex social cognition with neocortex containing only five layers instead of the mammalian standard of six, lacking granular layer IV (the primary thalamocortical input layer)—implying fundamentally different information-processing architecture achieving comparable cognitive outcomes.
The cerebellum's role in social cognition, documented in a 2020 consensus paper and Van Overwalle's 2024 Nature Reviews Neuroscience review, adds another dimension. The posterior cerebellum, especially Crus I and II, is specialized for social mentalizing—understanding others' mental states—through internal models combining motor commands with proprioceptive sensory inputs. Self-mentalizing activates anterior cerebellar lobules at the border of limbic and somatosensory networks, reflecting proprioceptive and emotionally triggered experiences. This places the spinocerebellar proprioceptive system directly within the social cognition architecture—in every brain, not only aphantasic ones.
Part III — Psychedelic mechanisms and the aphantasia dissociation¶
The REBUS model predicts what aphantasic psychedelic experience should look like¶
Carhart-Harris and Friston's REBUS model (2019) provides the theoretical framework for understanding psychedelic action within predictive processing. Psychedelics, via 5-HT2A receptor agonism on Layer V pyramidal neurons, relax the precision weighting of high-level priors (beliefs) while liberating bottom-up information flow. The default mode network, sitting at the apex of the brain's predictive hierarchy, encodes the narrative self as the highest-level prior. When psychedelics reduce DMN coherence—as consistently demonstrated from Carhart-Harris et al.'s seminal 2012 PNAS study through Gattuso et al.'s 2023 systematic review of 28 papers—the narrative self loosens, enabling revision of pathologically overweighted beliefs.
Psychedelic visual hallucinations, within this framework, are top-down predictions flooding downward with reduced precision weighting—essentially mental imagery with the "volume knob ripped off." Kometer et al. (2013) showed psilocybin decreases prestimulus parieto-occipital alpha power and strongly decreases visual-evoked potentials, with all effects blocked by the 5-HT2A antagonist ketanserin. A 2024 Molecular Psychiatry study using dynamic causal modeling found increased self-inhibition of visual regions under psilocybin combined with decreased bottom-up visual input sensitivity—consistent with the REBUS interpretation that visual experiences under psychedelics result from amplified top-down feedback.
The prediction for aphantasia follows logically but must be refined by subtype rather than treated as a blanket outcome. If visual hallucinations depend on the top-down imagery prediction system, the visual response should vary with the state of that system—while therapeutic benefit, if driven by DMN disruption and belief revision rather than visual content, should remain accessible regardless. The existing clinical and anecdotal evidence already demonstrates this subtype dependence rather than contradicting it:
Dos Santos et al. (2018) reported sustained imagery improvements after ayahuasca in acquired aphantasia—a case where the rendering hardware existed and was disconnected, and the psychedelic apparently reactivated dormant pathways. David Luke (2018) documented the counter-example: a congenital aphantasic with over 1,000 DMT experiences who never gained imagery—a case where the top-down predictive machinery was constitutively absent, leaving nothing for the psychedelic to amplify. Rebecchi (2023) described VVIQ scores changing from 16 (minimum) to 80 (maximum) after psilocybin in an autistic woman—effects persisting at 33-month follow-up—suggesting possible latent imagery capacity that crossed the amplification threshold under pharmacological pressure.
Bouyer and Arnold (2024) defined "Deep Aphantasia" as characterized by visual experience not strongly shaped by inhibitory feedback or prior expectations—subjects who lack apparent motion, 3D illusory contours, neon color spreading, and face pareidolia. This directly connects aphantasia to the REBUS framework: deep aphantasia may represent constitutive absence of the top-down predictive machinery that psychedelics amplify. If you have nothing to amplify, the visual channel stays silent—but the interoceptive channels (which are the same channels that process emotional, somatic, and mystical experiences in typical imagers) remain fully accessible. The fact that visual response varies while the underlying interoceptive substrate is shared across all participants is itself a demonstration of the unity of the system: one substrate, differential overlay.
Ketamine disrupts binding, not rendering — a mechanistic contrast¶
The distinction between psilocybin and ketamine mechanisms illuminates what happens when different layers of cognitive architecture are pharmacologically targeted. NMDA receptors function as "molecular coincidence detectors"—biological AND-gates requiring both presynaptic glutamate release and sufficient postsynaptic depolarization to open. This dual-gate property makes them the substrate for Hebbian learning: synapses that are simultaneously active pre- and post-synaptically strengthen their connections.
Ketamine, as a noncompetitive NMDA antagonist acting through open-channel block, disrupts this coincidence detection. Meuwese et al. (2013) demonstrated that ketamine reduces feature integration—impairing texture discrimination and figure-ground segregation by reducing recurrent feedback processing. Wiegand et al. (2023) showed ketamine reduces mentalizing (theory of mind) in healthy volunteers. Computationally, ketamine disrupts theta-gamma coupling in hippocampus (Neymotin et al., 2011; Caixeta et al., 2013) and disrupts thalamocortical feedforward and feedback signaling (Grent-'t-Jong et al., 2018).
Marguilho et al. (2023) proposed a unified model: ketamine's dissociative state results from disintegration of the Salience Network (encoding the bodily self), while its psychedelic state results from DMN disintegration (encoding the narrative self). This produces mechanistically distinct ego dissolution from psilocybin: ketamine loosens concept-to-concept bindings and the associative structure of self-representation; psilocybin amplifies top-down sensory predictions while relaxing their precision. Both reduce DMN coherence—Scheidegger et al. (2012) showed ketamine decreases resting-state DMN connectivity 24 hours post-infusion—but through different molecular pathways.
For aphantasic participants, this mechanistic distinction generates differential predictions. Psilocybin's visual effects should vary by aphantasia subtype (see predictions below), but ego dissolution, emotional intensification, and belief revision should remain accessible through non-visual pathways in all subtypes, because these operate through the shared interoceptive substrate. Ketamine's dissociative effects should be fully present regardless of imagery status, since NMDA blockade disrupts associative binding across all modalities, not specifically the visual simulation overlay. Testing these differential predictions in the same aphantasic participants across compounds would constitute the first pharmacological dissection of overlay-dependent versus substrate-level components of altered states.
The DMN and the question of what actually heals¶
A critical question emerges: if aphantasic individuals experience therapeutic benefit from psychedelics despite absent visual hallucinations, this would constitute strong evidence that DMN disruption and belief revision, not visual content, drive therapeutic outcomes. Multiple lines of evidence already point in this direction. Stoliker et al. (2024, Molecular Psychiatry) used dynamic causal modeling to show that psilocybin produces visual imagery through enhanced top-down connectivity from visual-association regions to earlier visual areas, while simultaneously increasing self-inhibition of both early and higher visual regions — a pattern consistent with reduced synaptic gain. If psychedelic visual imagery requires this specific top-down enhancement, and aphantasia involves constitutively reduced top-down visual connectivity (Milton et al., 2021; Liu, 2023), then deep aphantasics should show minimal visual response. Siegel et al. (2024, Nature) demonstrated that psilocybin causes global desynchronization of brain networks, with the degree of desynchronization correlating with mystical experience intensity (MEQ30). Crucially, this desynchronization affects the entire cortex — not specifically visual networks — meaning aphantasic brains should still undergo the network-level reorganization that drives therapeutic change. Non-hallucinogenic psychedelic analogues show antidepressant effects in rodent models. Mystical experience intensity (measured by the MEQ30, which is notably imagery-independent in its item content—focusing on unity, sacredness, positive mood, and transcendence rather than visual phenomena) predicts therapeutic outcomes more reliably than visual intensity. Post-treatment DMN "reset" (Carhart-Harris et al., 2017) correlates with symptom reduction. The 2025 REBAS study directly demonstrated that confidence in negative self-beliefs decreased following high-dose psilocybin, with entropy and subjective effects predicting the magnitude of belief revision. Brudner et al. (2025, J Psychopharmacol) extended this to a clinical treatment-resistant depression sample, providing preliminary support that mystical experiences predict antidepressant outcomes in psilocybin-assisted psychotherapy for both MDD and bipolar II — reinforcing the prediction that therapeutic outcomes should track MEQ30 rather than visual response.
The measurement instruments themselves carry a systematic bias worth noting. The 5D-ASC (5 Dimensions of Altered States of Consciousness) devotes its entire Visionary Restructuralization dimension—18 of 94 items including Complex Imagery, Elementary Imagery, and Audio-Visual Synesthesia subscales—to visual phenomena. Dose-response studies show the strongest dose-responses are found for Elementary and Complex Imagery items, meaning visually biased items dominate overall ASC scores. An aphantasic participant could score maximally on Oceanic Boundlessness (unity, spiritual experience, insightfulness) and Dread of Ego Dissolution while scoring zero on VR—yet their overall ASC score would appear "reduced." The MEQ30, by contrast, contains no items explicitly requiring visual imagery, meaning aphantasic participants could meet criteria for a "complete" mystical experience (≥60% on all four factors) while registering no visual phenomena. No published study has stratified 5D-ASC or MEQ30 data by imagery ability, despite this representing a straightforward analysis that could immediately illuminate whether visual phenomena contribute to, or merely accompany, therapeutic change.
Part IV — Body-based pathways to altered states and therapeutic access¶
Polyvagal architecture and the nucleus tractus solitarius as integration hub¶
Stephen Porges' polyvagal theory (1995, 2001, 2007, 2022, 2025) proposes a three-circuit autonomic hierarchy: the evolutionarily newest ventral vagal complex (myelinated vagal efferents from nucleus ambiguus, uniquely mammalian, supporting social engagement), the sympathetic nervous system (fight-or-flight), and the oldest dorsal vagal complex (unmyelinated vagal fibers, shared with reptilian ancestors, mediating shutdown/dissociation). Porges' concept of "neuroception"—unconscious subcortical threat assessment—describes how the nervous system continuously evaluates safety without conscious awareness.
While the theory's specific neuroanatomical claims face substantial criticism—Grossman (2023) states "there is broad consensus among experts that each basic physiological assumption is untenable," and Monteiro et al. (2018) found myelinated vagal fibers in lungfish contradicting the mammalian-exclusivity claim—the clinical framework captures something empirically important about autonomic state hierarchy and its relationship to therapeutic access. Porges' concept of "felt safety"—the subjective, physiologically grounded sense that the environment is safe enough for social engagement—is operationally distinct from cognitive safety assessment and serves as a prerequisite for therapeutic vulnerability.
The nucleus tractus solitarius (NTS) in the dorsomedial medulla provides the anatomical convergence point. The NTS receives afferents from cranial nerves VII, IX, and X carrying baroreceptor, chemoreceptor, pulmonary, cardiac, gastrointestinal, and taste information. McDougall and Bhatt (2009) found 75% of NTS neuron pairs receive monosynaptic primary afferent input, with 22% receiving two and 14% receiving three convergent inputs. Somatic afferents also converge on NTS neurons receiving vagal input, making NTS the "initial central site of mediation of somatosympathetic reflexes." This convergence explains why diverse physical interventions—carotid sinus massage, slow breathing, auricular vagus nerve stimulation, yoga inversions—produce overlapping autonomic effects: they all feed through the same brainstem integration hub.
Breathwork, vestibular disruption, and non-pharmacological altered states¶
The vestibular system—possibly the most ancient sensory system at ~500 million years—provides fundamental information for bodily self-consciousness. Lopez (2013) documented that vestibular disruption produces dramatic self-model alterations: distorted body image, out-of-body experiences, depersonalization, and altered agency. The temporo-parietal junction, where vestibular signals converge, is causally linked to out-of-body experiences and self-location. This means the embodied self-model has a component anchored in vestibular-proprioceptive processing that can be modulated through physical movement—again, in every brain, not only those without imagery.
Breathwork research has recently provided striking evidence. A 2025 study in Communications Psychology (Nature) demonstrated that circular breathwork induces altered states of consciousness comparable to psychedelics, predicted by decreases in end-tidal CO₂. A concurrent 2025 PLOS ONE study found high-ventilation breathwork alters cerebral perfusion in the left posterior insula and right amygdala/anterior hippocampus—regions involved in respiratory interoception—and scores high on the Oceanic Boundlessness dimension of the 5D-ASC, matching psychedelic experiences. Gerritsen and Band's (2018) respiratory vagal stimulation model proposes that slow breathing with extended exhalation phasically and tonically stimulates the vagus nerve, parsimoniously explaining health and cognitive benefits across meditation and yoga traditions.
Vagus nerve stimulation research further supports body-based routes to state change. Transcutaneous auricular VNS has demonstrated efficacy for treatment-resistant depression (systematic reviews showing significant benefit), PTSD symptom reduction (Bremner et al., 2021: 31% greater symptom reduction versus sham over 3 months), and inflammatory modulation (blocking IL-6 and IFN-γ responses to traumatic stress). These effects operate through NTS-mediated ascending pathways to amygdala, hypothalamus, and prefrontal cortex—bottom-up modulation of brain states through peripheral nerve stimulation.
Body-scan meditation as a contemplative pathway to the substrate¶
No published empirical study has directly tested meditation outcomes in aphantasic individuals—a clear research gap. However, convergent evidence supports the feasibility of body-based contemplative pathways. Fischer, Messner, and Pollatos (2017) demonstrated that an 8-week body-scan intervention improved interoceptive accuracy on heartbeat detection tasks, though subsequent meta-analyses suggest the effect size for body-scan specifically may be more modest than initially reported. Kok and Singer (2017), in the large-scale ReSource Project comparing four meditation types across 9 months of training, found that body scan produced the greatest state increases in interoceptive awareness among the four techniques examined (breathing meditation, body scan, loving-kindness, and observing-thoughts). Ehmann et al.'s 2025 meta-analysis showed long-term meditators exhibit increased bottom-up activation in the salience network.
Vipassana meditation is inherently non-visual, systematically directing attention through body sensations without visualization. The tradition's emphasis on equanimous observation of arising and passing sensations maps directly onto Craig's interoceptive hierarchy, training attentional processes from posterior insula (raw sensation) through mid-insula (integration) to anterior insula (meta-awareness). Typical imagers who practice body scan are learning to attend to the same interoceptive substrate that aphantasic individuals experience without the overlay — the practice strips away the imagery rendering to access what is underneath, which is the same in both populations.
Peter Levine's Somatic Experiencing (SE) provides the trauma-specific body-based modality. Payne, Levine, and Crane-Godreau (2015) described SE as directing attention to interoceptive, kinesthetic, and proprioceptive experience—explicitly connecting to Porges' polyvagal theory and Damasio's somatic markers. Brom et al.'s 2017 RCT (the first for SE) demonstrated significant PTSD symptom reduction with Cohen's d of 0.94–1.26, effects maintained at follow-up.
The guided interoception gap — formalizing what contemplative traditions already know¶
Guided imagery is among the most widely deployed therapeutic techniques in mental health practice. It appears in CBT protocols for anxiety (imaginal exposure, behavioral rehearsal), EMDR (safe-place installation, resource development), trauma processing (guided revisiting), hypnotherapy (scene construction), and standard relaxation training across virtually every therapeutic orientation. Guided imagery has its own professional organizations, certification programs, and insurance billing codes. It is, in practical terms, treated as a universal therapeutic tool—one that clinicians are trained to assume works for everyone.
For the approximately 1–4% of the population with significant aphantasia, guided imagery constitutes a systematic barrier to therapeutic access. Mawtus, Renwick, Thomas, and Reeder (2024, Collabra: Psychology, DOI: 10.1525/collabra.127416) conducted the first mixed-methods study of aphantasia's impact on mental healthcare, with results that are directly relevant to this framework. Among aphantasic individuals with PTSD, flashbacks were described as predominantly emotional and bodily rather than visual—the somatic flashback topology described in this document's contamination account. Only 3% of aphantasic participants reported that their mental health professional properly understood aphantasia. Imagery-based therapies, particularly CBT, were reported as ineffective, and the absence of visual intrusive imagery led to misdiagnosis toward depression rather than PTSD — because the DSM-5 diagnostic criteria for PTSD emphasize visual re-experiencing. Aphantasic clients report feeling "broken," "defective," or "resistant" when imagery-based techniques fail; therapists frequently interpret aphantasic non-response as therapeutic resistance, avoidance, or insufficient effort; and the resulting rupture in the therapeutic alliance—the very relationship that the literature now shows is a primary predictor of psychedelic and psychotherapy outcomes—compounds the original presenting problem.
Why formalizing guided interoception matters for everyone, not only those without imagery.
The case for guided interoception does not rest on it being a superior alternative to guided imagery. Imagery and interoception are not competing systems — they are layers of the same system, and interoception is the deeper layer that both populations share. The case rests on three observations about what happens when the overlay is compromised or absent.
First, vivid object imagery is a documented risk factor for PTSD severity. Kosslyn (2005) proposed that individuals with naturally vivid imagery are at higher risk of developing trauma-related intrusions. Morina, Leibold, and Ehring (2013), using an analogue trauma paradigm (n=67, exposure to distressing video), found that pre-stressor imagery vividness predicted the number, vividness, and emotional distress of intrusive memories, independently of trait anxiety and depression—though they noted the analogue design as a limitation requiring replication with real-world trauma survivors. Bryant and Harvey (1996) found that among PTSD patients specifically, imagery vividness correlated with flashback and nightmare frequency. Most recently, Yeung et al. (2025, Clinical Psychological Science) provided the strongest evidence to date. In two independent samples totaling 3,203 participants (806 trauma-exposed adults aged 18–83 and 493 undergraduates), they demonstrated that higher object imagery (vivid visual detail—shapes, colors, scenes) was associated with more PTSD symptoms across age and gender. Crucially, they also found a contrasting effect: higher spatial imagery (abstract representations of location and spatial relationships) was associated with fewer PTSD symptoms in the trauma-exposed sample, suggesting that spatial-schematic processing may help recontextualize traumatic memories rather than reliving them. The imagery overlay, for trauma survivors with strong object imagery, becomes a liability — the rendering engine replays the trauma.
Second, trauma can contaminate both the overlay and the substrate — but the topology of contamination differs. The safe-place visualization—a foundational technique in EMDR, CBT for PTSD, and standard trauma stabilization protocols—requires the client to construct and maintain a mental scene of safety and calm. But PTSD is characterized precisely by the hijacking of the imagery system: intrusive memories occur through hyper-activation of the amygdala and insula, disconnected from hippocampal contextual memory, and coupled with involuntary visual imagery mediated by the precuneus (Clark & Mackay, 2015, Frontiers in Psychiatry). The patient is being asked to use the same cortical rendering engine that produces their flashbacks to produce their safety. Research on refugee populations using guided imagery found that participants reported difficulties precisely because positive mental images "clashed harshly with their realities" (Kantor et al., 2020, JMIR Mental Health).
An honest account must acknowledge that the interoceptive substrate is not immune to trauma contamination. For survivors of physical abuse, sexual assault, torture, or medical trauma, the body itself carries trauma signatures. Somatic flashbacks are well-documented: survivors experience the sensation of being touched, grabbed, hit, or violated through interoceptive re-experiencing that operates through exactly the same body-based pathways proposed here as therapeutic routes. The "ick" sensation — visceral aversion, nausea, freeze responses — when body-based attention approaches affected regions is precisely a somatic marker that has been trauma-coded. Peter Levine's entire Somatic Experiencing framework is built on the premise that trauma is stored in the body, which means the substrate can be as contaminated as the overlay.
The critical difference is in the topology. Visual imagery contamination tends to be systemic — the entire rendering engine that produces flashbacks is the same hardware asked to produce the safe place, leaving no uncontaminated visual territory to work from. Somatic contamination is typically regional — specific body areas, sensation types, or postural configurations are triggering, while the interoceptive system as a whole retains substantial uncontaminated territory. A skilled therapist can begin with neutral somatic regions (feet on the floor, ambient temperature on the skin, breath at the nostrils) and work outward from safe ground. This is precisely how Levine's SE operates through titration and pendulation: carefully approaching and retreating from activated body areas rather than flooding the system. Ogden's Sensorimotor Psychotherapy and Price's MABT similarly emphasize therapist competence in recognizing and navigating somatic triggers.
Guided interoception thus offers a larger navigable safe zone than guided imagery for most trauma populations — not an immunity from contamination. For populations where trauma was primarily perceptual (witnessing violence, accidents), the imagery overlay may be heavily contaminated while the somatic substrate remains relatively accessible. For populations where trauma was primarily physical (torture, sexual abuse, severe medical procedures), the somatic substrate itself is compromised, requiring the titrated, co-regulated approach that SE already employs. For aphantasic survivors with somatic trauma, both the overlay (absent) and the substrate (compromised) present challenges, requiring the most careful clinical navigation — gradual, relationally anchored re-engagement with body-based knowing, beginning with non-threatened somatic regions and expanding the window of tolerance incrementally. Understanding these differential contamination patterns is itself an argument for why guided interoception needs formalization: clinicians need training in navigating somatic territory with the same sophistication they bring to imagery-based work.
Third, the world's oldest and most empirically successful contemplative traditions are already interoceptive, not imagery-based — and they were developed for people with full imagery capacity. Vipassana meditation, the technique through which the historical Buddha reportedly achieved enlightenment, is fundamentally an interoceptive practice. The Satipatthana Sutta's body scan—systematically directing attention through bodily sensations to observe impermanence—contains no visualization instructions. The U Ba Khin/S.N. Goenka tradition, which has trained millions of practitioners across cultures over 2,500 years, works exclusively through the observation of actual physical sensation: temperature, pressure, tingling, pulsation, pain. Jon Kabat-Zinn adapted this body-scan method into MBSR (Mindfulness-Based Stress Reduction) in the 1970s, producing what has become one of the most empirically validated psychological interventions in existence.
Zen meditation (zazen/shikantaza—"just sitting") directs attention to posture, breath, and present-moment somatic awareness without any imagery component. Centering Prayer in the Christian contemplative tradition releases all mental images and thoughts in favor of simple interior consent. The Quaker practice of "expectant waiting" involves sitting in silence attuned to bodily promptings of the Spirit without visual content. Sufi dhikr practices combine rhythmic breathing with physical movement. The Orthodox Christian hesychast tradition anchors prayer in the heartbeat.
These traditions did not develop body-based practices as accommodations for people who couldn't visualize — their practitioners have full imagery capacity. They developed them because attending to the interoceptive substrate directly, bypassing the imagery overlay, produces deeper and more reliable access to altered states, emotional regulation, and what each tradition frames as contact with fundamental reality. This is the strongest possible evidence that the substrate, not the overlay, is where the deepest therapeutic and contemplative work happens — for everyone.
Existing body-based modalities and what's missing¶
Several body-based therapeutic approaches already exist: Gendlin's Focusing (1978, 1981), which developed the concept of the "felt sense" and the Experiencing Scale (EXP) that proved a better predictor of therapy outcomes than the specific therapeutic modality employed — notably, this finding held for all clients, not only those without imagery; Price's Mindful Awareness in Body-oriented Therapy (MABT), which integrates manual/touch-based therapy with mindfulness and psychoeducation, addressing Craig's three interoceptive components (identifying, accessing, appraising); Winhall's Felt Sense Polyvagal Model (2021), which bridges Gendlin's phenomenology with Porges' autonomic framework through the Six F's (Flock/Fight/Flight/Freeze/Faint/Fold); Levine's Somatic Experiencing; and Ogden's Sensorimotor Psychotherapy.
What is missing is not individual techniques but a coherent, named clinical framework—guided interoception—that occupies the same institutional position as guided imagery: with standardized protocols, training certifications, outcome measures, and explicit recognition as a primary therapeutic pathway. This framework serves three overlapping populations: individuals whose imagery overlay is absent (aphantasia), individuals whose imagery overlay is contaminated by trauma (PTSD, CPTSD, dissociative disorders), and — given the contemplative tradition evidence and Gendlin's outcome data — potentially all individuals seeking deeper access to the interoceptive substrate that imagery normally obscures.
Proprioceptive spatial construction — an observational note and proposed construct¶
A preliminary phenomenological observation suggests an additional dimension of non-visual spatial cognition that extends the substrate beyond evaluation into active spatial reasoning. An aphantasic individual, when asked to construct a spatial model of their own cranial anatomy, discovered they could do so through a "traveling proprioceptive journey" — placing a hand on the head and building a three-dimensional structural representation through touch-position tracking, then transferring that spatial reference to the space in front of them by maintaining proprioceptive coordinates while moving the hand. The constructed model could be navigated, disassembled, and manipulated — and extended to objects never physically touched, built from conceptual knowledge projected into proprioceptive coordinate space. Critically, this capacity was available only with eyes closed; opening the eyes immediately disrupted the proprioceptive spatial model. A quiet, meditative cognitive state was also required — narrative processing degraded the signal.
We term this phenomenon proprioceptive spatial construction (PSC): the generation, manipulation, and navigation of spatial models of external objects or concepts using the body's proprioceptive system as the primary representational medium, in the absence of visual imagery and without requiring prior tactile experience of the represented object. PSC is distinct from existing imagery categories in the literature: it is not kinesthetic imagery (which rehearses one's own motor actions), not proprioceptive imagery as currently defined (which imagines one's body at a displaced position), not haptic imagery (which replays stored touch experiences), and not tactile imagery (which imagines cutaneous sensations). In PSC, the hands serve as coordinate scaffolding — the instrument generating a spatial representation of something else, not the thing being represented. The phenomenon is generative (building novel models from conceptual knowledge), object-directed (representing external entities through the body), and manipulable (supporting active spatial operations through ongoing proprioceptive input). A detailed taxonomic analysis distinguishing PSC from all existing imagery categories and reviewing supporting evidence from seven research domains is available as a supporting document (Kirkland, 2026, "Proprioceptive Spatial Construction").
The eye-closure requirement has a precise neuroscientific explanation that strengthens the overlay/substrate model. Rock and Victor's (1964) classic visual capture effect is not merely perceptual bias — it reflects active neural suppression. Ernst and Banks (2002, Nature) demonstrated that the brain combines visual and proprioceptive information via maximum-likelihood estimation, weighting each modality by its reliability; removing visual input forces 100% reliance on proprioceptive estimates. More strikingly, Wasaka and Kakigi (2012, NeuroImage) showed through neuroimaging that visual-proprioceptive discordance actively inhibits primary somatosensory cortex — vision doesn't just override proprioception, it suppresses the cortical processing that proprioceptive spatial reasoning requires. The overlay doesn't merely obscure the substrate. It actively inhibits it.
This has implications beyond aphantasia. The contemplative traditions' universal emphasis on eyes-closed practice — Vipassana body scan, zazen, Centering Prayer, hesychast heart-prayer — is not arbitrary convention. It is de-suppression of the substrate. Closing the eyes removes the neurological inhibition that vision imposes on somatosensory cortex, enabling the interoceptive and proprioceptive processing that these traditions cultivate. Lazar et al. (2005, NeuroReport) found that experienced insight meditators had increased cortical thickness specifically in somatosensory cortex — consistent with enhanced proprioceptive processing capacity through sustained practice of visual de-suppression. Graziano (1999, Neuron) identified bimodal neurons in premotor and posterior parietal cortex with receptive fields literally anchored to the hand position — in the absence of visual input, these neurons operate purely on proprioceptive coordinates, which is the condition under which PSC occurs.
PSC may represent the specific mechanism underlying the "sensorimotor strategy" that aphantasia researchers have consistently identified as a preferred alternative to visual imagery (Reeder et al., 2024; Kay et al., 2024) but have not investigated as a spatial construction modality in its own right. If so, it extends the framework's core claim: the substrate is not merely an evaluation system (somatic markers, gut feelings) but a complete cognitive system that includes active spatial reasoning, model construction, and manipulation — all operating through body-based channels that are normally suppressed by the overlay's visual dominance. The visual rendering is epiphenomenal to the spatial computation, just as the framework predicts visual hallucinations are epiphenomenal to psychedelic therapeutic mechanisms. In both domains, the overlay adds rendering, not cognition — and the cognition happens at the substrate level regardless.
Guided interoception protocols could incorporate proprioceptive spatial exercises — touching, tracing, body-mapping — as ways of accessing this substrate. This possibility warrants formal investigation.
Part V — Therapeutic gating, developmental invalidation, and the division of therapeutic labor¶
The therapeutic relationship as gatekeeper to altered states¶
For trauma populations, hypervigilance may constitute a pharmacological barrier that no drug alone can overcome. Chronic noradrenergic activation from the locus coeruleus—sensitized by stress through amygdala-CRH pathways (Valentino and Van Bockstaele, 2008)—locks individuals into sympathetic mobilization that suppresses the ventral vagal social engagement system. Van der Kolk's (2014) framework holds that trauma literally reshapes brain and body, producing perpetual autonomic alarm states where "the body needs to learn that the danger has passed."
Murphy et al. (2022) demonstrated that therapeutic alliance predicts psilocybin outcomes through sequential mediation: strong alliance → greater emotional breakthrough and mystical experience → improved clinical outcomes. Weaker alliance before the second psilocybin session directly predicted higher depression scores at endpoint (β = −0.49). Levin et al. (2024) extended this to 12-month follow-up, finding that the bond subscale (emotional connection)—not task alliance—predicted outcomes. Krediet et al. (2024) found alliance predicted PTSD outcomes in MDMA-assisted therapy. Modlin et al. (2025) specifically warned that avoidance, control, dissociation, and hypervigilance become "particularly salient during psilocybin treatment" in trauma populations, recommending trauma-informed protocols.
This evidence reframes the therapeutic question: the drug is not the therapeutic agent—it is the catalyst that, given sufficient felt safety, enables the nervous system to access states where rigid self-models can be revised. For aphantasic individuals with trauma histories, this insight is doubly relevant. Not only must felt safety be established, but the standard preparation protocols—which often rely on guided imagery for anxiety reduction—must be adapted to interoceptive approaches.
The division of therapeutic labor¶
The therapeutic relationship and body-based intervention serve complementary but mechanistically distinct functions within the same integrated system. Talk therapy—the relational container—provides neuroceptive safety cues: prosodic voice patterns, attuned facial expressions, co-regulation through physiological synchrony. These operate through Porges' social engagement system to downregulate defensive autonomic states. The therapeutic alliance builds the felt safety prerequisite for vulnerability.
Body-based intervention—whether pharmacological (psilocybin, ketamine) or non-pharmacological (breathwork, somatic experiencing, vagal stimulation, EMDR bilateral stimulation)—accesses and modifies the body's stored threat-response patterns through the NTS, vagal afferents, baroreceptor reflexes, vestibular system, and ascending interoceptive pathways. These operate at the substrate level — the same interoceptive system that functions in every brain, regardless of imagery status.
Neither alone is sufficient, and the sequence matters. Body-based intervention without relational safety risks retraumatization—the nervous system interprets somatic activation without co-regulatory support as confirmation of threat. Relational safety without body-based intervention may produce insight without somatic change—the client understands their patterns intellectually while their autonomic nervous system continues operating in survival mode. The therapeutic division of labor requires establishing relational container first (felt safety through co-regulation), then engaging body-based intervention within that container. This applies equally to pharmacological and non-pharmacological contexts.
Developmental invalidation of the somatic confirmation channel¶
The developmental implications extend beyond clinical practice into fundamental questions about how educational systems recognize — or fail to recognize — cognitive processing that operates through the interoceptive substrate rather than the imagery overlay. Krause, Mendelson, and Lynch (2003) demonstrated that childhood emotional invalidation (parental punishment, minimization, and distress in response to negative emotion) produces chronic emotional inhibition in adulthood, with the relationship fully mediated by a style of suppressing emotional experience and expression. Linehan's (1993) concept of the "invalidating environment"—where a child is repeatedly told that their perceptions, feelings, or processing style are wrong—produces lasting damage to the capacity for self-trust and self-validation.
For every child, somatic markers provide a body-based evaluation signal that operates alongside and often prior to conscious verbal reasoning. Damasio's Iowa Gambling Task data showed that healthy participants generated anticipatory physiological responses before they could articulate any conscious strategy. The body "knew" before the mind could explain. In typical development, this somatic confirmation signal is gradually integrated with verbal-analytical reasoning and with the imagery overlay—the child learns to feel, imagine, and explain their understanding through multiple layers simultaneously.
For the aphantasic child, the somatic marker system is the primary cognitive layer available for conscious report. When such a child arrives at a correct answer through body-based evaluation but cannot demonstrate the standard visual-spatial processing steps, the educational demand to "show your work" becomes a form of systematic invalidation of their actual cognitive process. Research on mathematically gifted children documents this phenomenon: Greenes (1981) found that gifted students often skip over steps and are unable to explain how they arrived at the correct answer due to their "intuitive understanding of mathematical function and processes." The Davidson Institute's review of gifted math education notes that such students prefer conceptual depth over computational "how-to" processes.
This creates a specific developmental injury that compounds in three ways:
The cognitive channel is invalidated. The child's somatic confirmation signal—their primary means of knowing—is treated as insufficient, incorrect, or non-existent by educational authority figures. The child learns that their way of knowing doesn't count, regardless of whether it produces correct outcomes.
The invalidation is structurally invisible. Unlike emotional invalidation, which can at least be recognized as interpersonal harm, cognitive-channel invalidation is embedded in standard pedagogical practice. "Show your work" is not experienced by teachers as invalidation—it is experienced as standard educational expectation. The aphantasic child cannot articulate what is being suppressed because they lack the metacognitive vocabulary to describe a processing mode that most people do not share and that has no formal name.
The suppression reinforces itself. As the somatic confirmation channel is repeatedly invalidated, the child learns to distrust it. This learned distrust does not eliminate the channel—the body continues generating evaluation signals—but it creates a chronic dissonance between what the body knows and what the mind permits itself to trust. In adulthood, this manifests as the experience of having a strong somatic sense that something is correct or important while simultaneously doubting that sense, seeking external verification, and being unable to act on body-based knowledge with confidence.
The ERIC somatic/embodied learning review (2002) identified this as a systemic cultural issue: Western education has been dominated by the separation of cognitive knowledge from embodied knowledge and the distrust of bodily knowing. The Strozzi Institute's somatic education framework explicitly names this process: somatic intuitive capacity "has been pruned out of us by a rationalistic education" that teaches individuals "to ignore the deeper messages of our soma and to rely solely on our cognitive processes."
This developmental invalidation can intersect with trauma-driven hypervigilance to produce a doubled suppression. The somatic confirmation channel is suppressed both by educational invalidation ("that's not how you're supposed to know things") and by trauma-driven hypervigilance ("trusting your own perception is not safe"). These are architecturally independent suppression mechanisms—one cultural, one survival-based—but they produce the same functional outcome: a person who has a computationally powerful somatic evaluation system that they have been systematically trained not to trust.
Recovery of the somatic confirmation channel — through Focusing, body-scan meditation, somatic experiencing, or other interoceptive training — may therefore require addressing both layers of suppression: the educational invalidation (through psychoeducation about aphantasia, somatic cognition, and legitimate cognitive processing through the interoceptive substrate) and the trauma-driven distrust (through co-regulation, felt safety, and gradual re-engagement with body-based knowing in a relationally safe context). Combining these recovery pathways constitutes a clinical protocol that does not yet exist but that the framework makes both theoretically coherent and practically necessary. Importantly, this protocol would benefit not only aphantasic individuals but any person whose relationship with their own somatic knowing has been damaged — which the ERIC review and contemplative tradition evidence suggest is the cultural norm rather than the exception.
Implications for educational assessment and cognitive diversity¶
The educational dimension raises broader questions about whether current assessment practices systematically disadvantage students whose cognition operates primarily through the interoceptive substrate rather than the imagery overlay. Standard mathematical assessment, writing evaluation, and creative problem-solving rubrics all embed assumptions about cognitive processing that privilege the ability to externalize visual-spatial reasoning steps.
When this observation is combined with the aphantasia literature—particularly the findings that aphantasics perform mental rotation tasks more slowly but more accurately using analytic rather than imagery-based strategies (Kay et al., 2024), and that aphantasics score modestly higher on IQ tests despite lacking the imagery substrate assumed to underlie visuospatial reasoning (Milton et al., 2021)—a hypothesis emerges: some proportion of "gifted underperformers" may be individuals whose cognition operates primarily through the interoceptive substrate, producing valid outcomes through processing pathways that current assessment tools cannot detect or evaluate.
This hypothesis is testable. A study administering the VVIQ alongside standard academic assessments to a population of students identified as "gifted but underperforming" or "inconsistently performing" could determine whether aphantasia or hypophantasia is overrepresented in this group. If confirmed, the implications would extend beyond clinical practice into educational policy: the development of assessment methods that can evaluate cognitive outcomes without requiring demonstration of imagery-based processing steps, and the training of educators to recognize and validate somatic-intuitive cognition as a legitimate cognitive style rather than a deficit to be corrected.
Part VI — Neurodivergence, consciousness, and the mechanics of mystical experience¶
Mirror-touch synesthesia and the universality of somatosensory social processing¶
Mirror-touch synesthesia (MTS), affecting approximately 1.6% of the population (Banissy et al., 2009), represents a state where the somatosensory mirror system—universally present but typically subthreshold—crosses into conscious awareness. Blakemore et al. (2005) first demonstrated via fMRI that a mirror-touch synesthete showed significantly higher activation in primary and secondary somatosensory cortices and bilateral anterior insula during observation of touch. Bolognini et al. (2013) induced MTS-like experiences in non-synesthetes through tDCS increasing somatosensory cortex excitability, providing causal evidence that MTS lies on a continuum with normal processing.
Ward and Banissy's (2015) Self-Other Theory proposes MTS stems from disturbances in distinguishing self from others—an over-extension of the bodily self. Banissy et al. (2011) demonstrated that MTS synesthetes show superior facial expression recognition but not facial identity recognition—precisely the pattern expected if the somatosensory mirror system provides social-emotional processing through the interoceptive substrate rather than through the imagery overlay. MTS makes visible what the mirror neuron literature has long suggested: every brain processes others' experiences somatically. In typical brains, this processing remains subthreshold — felt as vague empathy or "vibes" — and is frequently overridden in conscious report by imagery-based mentalizing ("I imagined how they felt"). In MTS, and potentially in aphantasic individuals with intact somatosensory mirroring, the body-based social cognition is experienced directly as what it is.
No published study has examined MTS co-occurrence specifically with aphantasia—a significant gap. Dance et al. (2021) showed grapheme-colour synesthesia can co-occur with aphantasia and that aphantasics report more autistic traits. Baron-Cohen et al. (2016) documented MTS co-occurring with autism. If mirror-touch synesthesia can occur in aphantasia, it would confirm that body-based social cognition operates through the interoceptive substrate independently of the imagery overlay — and that the substrate processes social information in everyone, whether or not they are aware of it.
Neurodivergence as the social prediction engine under strain¶
Robin Dunbar's social brain hypothesis (1998, 2024) establishes that primate neocortex size correlates quantitatively with social group size—social cognition is likely the primary evolutionary driver of cortical complexity. When this social prediction engine encounters systematic prediction errors, the consequences are illuminating. Van de Cruys et al.'s HIPPEA framework (2014) proposes that autistic brains assign uniformly high and inflexible precision to prediction errors, leading to overfitting—strong but non-generalizable predictions that work in specific contexts but fail to scale to the fluid, noisy domain of social interaction.
Kohls et al. (2018) demonstrated that the reward circuit in autism goes into overdrive for personalized restricted interests while showing weaker activation for social rewards. Pelphrey hypothesized that brain areas evolved for social processing may be redeployed to focus on objects and concepts when social stimuli lack their typical pull—analogous to how blind people's visual cortex rewires for Braille. Milton's double empathy problem (2012, 2022) reframes social difficulties as bidirectional between differently disposed neurotypes rather than unilateral deficits. Research by Crompton et al. (2020) showing that autistic-autistic communication is as effective as non-autistic communication supports this framing.
This connects to the simulation-lucid phenotype through the observation that neurodivergent cognition often involves processing through the substrate rather than the overlay — which standard assessment tools are not designed to detect. Kay, Keogh, and Pearson (2024) showed aphantasics perform mental rotation tasks more slowly but more accurately than typical imagers, using analytic rather than imagery-based strategies. Milton et al. (2021) found aphantasics scored modestly but significantly higher on IQ tests despite lacking the imagery overlay assumed to underlie visuospatial reasoning. Wen et al. (2017) demonstrated that Raven's Progressive Matrices embed both visuospatial and verbal-analytic reasoning pathways with distinct neural substrates—the test can be solved without mental imagery through propositional reasoning via the right inferior frontal gyrus, dorsal anterior cingulate, and temporoparietal junction.
What mystical experience actually is: a first-principles account¶
The neuroscience of mystical experience converges on DMN suppression as a common correlate across meditation (Brewer et al., 2011), psychedelics (Carhart-Harris et al., 2012), and religious practice. Newberg's neurotheology program showed that both Tibetan Buddhist meditators (visualization-based) and Franciscan nuns (verbal prayer-based) exhibited decreased activity in the superior parietal orientation area—the region maintaining self-other spatial boundaries—with shared patterns despite different practices. Crucially, Cristofori et al.'s (2016) study of Vietnam veterans with traumatic brain injuries found that lesions to dorsolateral prefrontal cortex increased mystical experiences, supporting the "Executive Inhibition Hypothesis"—mystical states emerge when executive control is reduced, independent of imagery capacity.
The framework developed in this document provides a complete first-principles account of what is happening during these experiences — one that validates the phenomenology while grounding it in identifiable neuroanatomy.
Craig's model establishes that the anterior insular cortex generates a progressive meta-representation of integrated body state and proposes this as the neural substrate of subjective awareness itself. Under normal conditions, this integration is parcellated — the AIC maintains distinctions between self and environment, between "my body" and "the world," between this moment and the narrative of my life. The DMN, sitting at the apex of the predictive hierarchy, maintains the narrative self: the story of who you are, where you end and others begin.
Direct neurological evidence for this mechanism comes from Picard's work on ecstatic epilepsy (2023). Patients with seizures originating in or propagating through the operculo-anterior insular region report mystical/ecstatic experiences — unity, bliss, heightened self-awareness, dissolution of self-other boundaries — that are phenomenologically indistinguishable from those produced by deep meditation or psychedelics. Ictal SPECT confirms increased blood flow in the anterior insula during these seizures. Picard proposes that interoceptive predictive coding in the insula is disrupted during the ecstatic state, producing an unmediated integration of body-state information that bypasses the normal parsing and parcellation. This constitutes the strongest direct evidence that the AIC integration process is the actual locus of mystical experience — not a correlate, but the mechanism itself.
When sustained contemplative practice, psychedelic pharmacology, breathwork, or spontaneous state shifts suppress DMN coherence and reduce activity in the superior parietal orientation area, the systems that maintain self-other boundaries go offline. Simultaneously, the interoceptive substrate — Craig's hierarchy from posterior insula through mid-insula to AIC — achieves a state of maximum integration without the parcellation that normally constrains it. The phenomenological result is the experience of unity — not as metaphor, but as the actual computational event of boundary-dissolution in the system that generates the sense of self. Everything becomes one because the processing that normally maintains separateness has temporarily ceased.
Panksepp's subcortical emotional systems, particularly SEEKING (engaged openness, curiosity, vital exploration) and CARE (warmth, nurturing, unconditional connection), are normally modulated and constrained by cortical executive control. When executive systems are suppressed — by psychedelics reducing DMN coherence, by deep meditation reducing prefrontal activity, by Cristofori's TBI lesions removing dorsolateral prefrontal constraint — these subcortical systems operate with reduced top-down restriction. The phenomenological result is the experience of profound connection, unconditional warmth, and engaged openness that contemplative practitioners across every tradition describe. These are not imagined experiences. They are the direct phenomenology of ancient emotional systems operating without their usual cortical constraints.
The MEQ30 factors map directly onto this mechanistic account: Mystical (unity = boundary dissolution via parietal/DMN suppression, interoceptive integration reaching maximum coherence), Positive Mood (peace, joy, love = subcortical CARE and SEEKING liberated from cortical modulation), Transcendence of Time/Space (= temporal processing disrupted when DMN narrative sequencing goes offline; the AIC's "eternal now" replaces the narrative self's autobiographical timeline), Ineffability (= the experience is generated by interoceptive and subcortical systems that operate beneath the narrative/linguistic cortex, so the narrative cortex literally cannot represent it in words after the fact — it was not online during the event it is being asked to describe).
These experiences are real neurological events, happening locally, through the interoceptive-somatic substrate that the simulation-lucid framework identifies as the universal system beneath the imagery overlay. The contemplative traditions were right about the method (body-based attention, not visualization), right about the phenomenology (unity, peace, dissolution of self-boundaries), and right about the pathway (through the body, not through conceptual thought). What the framework adds is the mechanistic account: these experiences arise from Craig's interoceptive hierarchy achieving maximum integration while the cortical systems that normally maintain self-other boundaries are suppressed.
The attribution to an external higher power is the narrative cortex — coming back online after the experience — constructing an explanation for an event that occurred while the narrative system was offline. The brain that experienced unity cannot narrate unity while it's happening, because narration requires the self-other distinction that unity dissolves. The explanation is always retroactive, always constructed by a system that wasn't there for the event it's explaining. The most available cultural framework for "I experienced something profoundly real that I cannot explain and that dissolved my sense of separate self" is, for most humans throughout most of history, the divine.
This is not a reductive account. The experience is real. The neural changes are real. The lasting personality changes documented by Griffiths et al. — 58% rating psilocybin-occasioned mystical experience among the five most spiritually significant of their lives — are real. Establishing that divine unity experiences are generated by the interoceptive-somatic substrate through the body-based practices that contemplative traditions refined over millennia, and that they produce lasting measurable changes in brain connectivity, does not diminish the experience. It validates the tradition's methodology while grounding the phenomenology in the hardware that actually produces it. It tells the meditator: your practice works, here is why, and the "where" is not somewhere else — it is here, in your body, in the system that connects your gut to your insula to your awareness. The experience of unity is what happens when you stop maintaining the illusion of separateness. That is what every contemplative tradition has been saying. The neuroscience agrees.
And here is where the simulation-lucid phenotype's contribution becomes most pointed: because aphantasic individuals experience the interoceptive substrate without the imagery overlay, they can report on what these experiences actually are at the hardware level. A typical imager who achieves a mystical state will report it through visual metaphors — light, vast spaces, radiance, visions — because their cortex renders interoceptive events into visual representations after the fact. The aphantasic experiencer, if they access the same state through the same substrate, would report the experience as it is: body-based, interoceptive, proprioceptive. No rendering. No visual metaphors layered on top. This makes the simulation-lucid phenotype not just a research tool but an experiential window into what these states are composed of beneath the imagery overlay that normally dresses them up — much as someone with congenital albinism can describe skin structures that exist in everyone but are normally hidden by pigmentation.
Face processing reveals the subcortical social detection system¶
The face processing literature illuminates how social cognition operates across subcortical and cortical levels. While the fusiform face area (Kanwisher et al., 1997) provides holistic cortical face processing, a rapid subcortical pathway—superior colliculus → pulvinar → amygdala—enables face detection within 45–88 milliseconds, before cortical processing begins. Wang et al. (2023) provided direct intracranial EEG evidence for this pathway responding to invisible fearful faces without cortical involvement. McFadyen et al. (2019) demonstrated that this subcortical connection is uninfluenced by spatial frequency or emotion, operating as a universal rapid social detection system — yet another instance of a substrate-level process operating in every brain, beneath the cortical overlay.
The aphantasia-prosopagnosia relationship remains debated. Monzel et al. (2023) found aphantasics show mild general visual recognition deficits (not face-specific), while a 2025 preprint (Maw et al.) claims 14–36% of aphantasics meet criteria for developmental prosopagnosia. Dance et al. (2023) found a striking dissociation: aphantasics showed weaker face recognition but fully intact ability to construct facial composites from memory—suggesting face memory is preserved through substrate-level pathways even when overlay-based face recognition is impaired.
Part VII — Toward a research program¶
What the literature reveals about the novelty of the proposed framework¶
Systematic searching confirms that the term "simulation-lucid phenotype" does not exist in the literature, nor does any equivalent framing. The closest conceptual analog is Balaban and Ullman's (2025) "Physics versus Graphics" framework in Trends in Cognitive Sciences, which describes aphantasia as "broken rendering" with preserved "physical simulation"—but this does not invoke interoceptive-somatic systems or evolutionary framing. Aphantasia has been recognized as a natural experiment (Liu, 2025; Zeman, 2024), and the aphantasia-interoception connection is an active research area (Silvanto and Nagai, 2025). However, no researcher has proposed using aphantasia as a dissociation tool in psychedelic research to separate visual from therapeutic mechanisms—though the 2024 Molecular Psychiatry neural mechanisms paper explicitly suggests this as a future direction.
The individual components of the proposed framework all have strong empirical grounding:
- Aphantasia as absence of the cortical sensory simulation overlay (robust evidence)
- The overlay/substrate distinction mapping onto the ventral/dorsal stream architecture, with aphantasia primarily affecting ventral (object) processing while dorsal (spatial) processing remains intact (strong evidence from Bainbridge et al. 2021, OSIQ data, Reeder et al. 2024, Phillips 2025)
- The interoceptive-proprioceptive system as a universal cognitive substrate present in all brains (strong evidence from Craig, Damasio, Panksepp)
- Vision actively suppressing somatosensory cortex, not merely overriding it, making eyes-closed practice a de-suppression mechanism (Ernst & Banks 2002, Wasaka & Kakigi 2012)
- Psychedelic visuals as amplified top-down predictions through the overlay (REBUS model, well-supported)
- DMN disruption as likely therapeutic mechanism operating at the substrate level (consistent evidence across psychedelics and ketamine)
- Therapeutic alliance as gatekeeper to altered states (emerging but consistent evidence)
- Body-based pathways to contemplative and therapeutic states developed for and by people with full imagery capacity (strong evidence for breathwork, body-scan, somatic experiencing; 2,500-year contemplative tradition record)
- Vivid object imagery as PTSD risk factor (converging evidence from Yeung et al. 2025, Morina et al. 2013, Bryant & Harvey 1996)
- Trauma contamination of both overlay (visual flashbacks) and substrate (somatic flashbacks), with differential topology (consistent with intrusive memory neuroscience, somatic experiencing literature)
- Developmental invalidation of somatic confirmation channel (supported by Krause et al. 2003, Linehan 1993, gifted education literature)
- First-principles mechanistic account of mystical experience as interoceptive integration with boundary-dissolution (supported by Craig's AIC model, Picard 2023 ecstatic epilepsy, DMN/parietal suppression findings, Cristofori TBI data, Panksepp's subcortical systems)
The novel synthesis—connecting these into a unified framework where aphantasic participants make visible the universal interoceptive substrate by removing the imagery overlay that normally obscures it, much as albinism reveals melanin synthesis pathways visible in all skin—does not yet exist. Koenig-Robert et al.'s 2025 paper in Cortex on risks of psychedelics "opening the mind's eye" in aphantasia comes closest to the clinical intersection but focuses on safety concerns rather than methodological opportunity.
A proposed research architecture¶
The strongest immediate study design would be a within-subjects, cross-compound comparison of complete aphantasics — stratified by congenital/deep versus acquired subtypes — and matched typical-imagers under psilocybin, ketamine, and placebo. The subtype distinction is critical: congenital aphantasia likely reflects architecturally absent top-down visual pathways (nothing to amplify), while acquired aphantasia may reflect disrupted connectivity in preserved architecture (potentially restorable under pharmacological amplification). Primary outcome measures should include the MEQ30 (imagery-independent mystical experience), 5D-ASC with subscale decomposition (allowing separate analysis of visual versus non-visual altered-state dimensions), and standardized therapeutic outcome measures for depression or PTSD. Critically, the study should add interoceptive measures (MAIA-2), heartbeat evoked potentials, and HRV/vagal tone indices to capture substrate-level processing during altered states.
Research priorities¶
-
Cross-compound aphantasia study. Complete aphantasics stratified by subtype — congenital/deep (VVIQ=16, confirmed by binocular rivalry, pupillometry, AND absence of top-down visual illusions per Bouyer & Arnold 2024) versus acquired (documented onset, preserved visual illusion susceptibility) — and matched typical-imagers under psilocybin, ketamine, and placebo. Primary measures: MEQ30, 5D-ASC with subscale decomposition, therapeutic outcomes, interoceptive measures (MAIA-2), HRV/vagal tone. The subtype stratification is essential: if congenital and acquired aphantasics show divergent visual responses but convergent therapeutic outcomes, this provides the cleanest evidence that the overlay is epiphenomenal to the therapeutic mechanism operating at the substrate level.
-
Retrospective 5D-ASC/MEQ30 stratification. Existing psychedelic trial datasets re-analyzed by VVIQ score to determine whether visual phenomena predict or merely co-occur with therapeutic outcomes. This is the lowest-cost, highest-yield immediate analysis.
-
Guided interoception protocol development. Formalization of body-based therapeutic pathways as a coherent clinical framework—drawing from Focusing, MABT, SE, body-scan meditation, and the Felt Sense Polyvagal Model—with standardized protocols, training materials, and outcome measures. Protocols must incorporate somatic trigger navigation for populations with physical/sexual trauma, where body regions themselves carry trauma signatures. The SE principles of titration and pendulation provide the clinical model: begin with neutral somatic territory, work outward carefully. This framework serves all populations — those without the overlay (aphantasia), those with a trauma-contaminated overlay (PTSD/CPTSD), and those seeking deeper access to the substrate that the overlay normally obscures (contemplative practitioners, anyone).
-
Imagery vividness as PTSD risk factor screening. Integration of VVIQ (or the Object-Spatial Imagery Questionnaire, per Yeung et al. 2025) into standard trauma assessment protocols — not only to identify aphantasic patients who need interoceptive pathways but to identify high-vividness patients whose object-imagery overlay may be actively exacerbating their condition. The Yeung et al. finding that spatial imagery is protective while object imagery is harmful suggests differential clinical implications at the overlay level.
-
Educational screening study. VVIQ administered to students identified as "gifted but underperforming" or "inconsistently performing" to test whether aphantasia or hypophantasia is overrepresented in this group, which would support the developmental invalidation hypothesis.
-
Mirror-touch synesthesia co-occurrence. Survey of aphantasic populations for MTS prevalence, testing whether body-based social cognition operates through the substrate independently of the overlay.
-
Proprioceptive spatial construction (PSC) in aphantasia. Formal investigation of PSC as a distinct cognitive modality: comparison of proprioceptive spatial accuracy and construction ability in aphantasic versus typical-imagery populations under eyes-open and eyes-closed conditions, testing whether removing visual dominance (de-suppressing the substrate) differentially liberates body-based spatial reasoning in aphantasia. Predicted neural signature: activation of posterior parietal cortex (IPS, SPL) for spatial transformation, supramarginal gyrus for proprioceptive-spatial integration, somatotopic recruitment of hand regions in primary somatosensory cortex, deactivation of primary visual cortex, and DMN suppression — a pattern distinguishable from both kinesthetic imagery (which co-activates motor structures) and visual spatial imagery (which recruits occipital cortex). No study has tested for this signature because PSC has not been identified as a distinct target for investigation.
Differential predictions¶
These predictions are testable and falsifiable:
-
Psilocybin visual response should vary by aphantasia subtype, not uniformly. Deep/congenital aphantasics (constitutively absent top-down visual architecture, per Bouyer & Arnold 2024) should show minimal or absent Visionary Restructuralization, consistent with Luke's (2018) report of zero imagery across 1,000+ DMT sessions — there is nothing in the overlay to amplify. Acquired aphantasics (intact architecture with disrupted connectivity) may show partial or full VR emergence, consistent with Dos Santos et al. (2018) and Rebecchi (2023), as psilocybin's massive amplification of top-down signals may temporarily force through weakened overlay connections. Intermediate/shallow aphantasics with latent capacity below threshold may experience first-ever visual phenomena as pharmacological pressure pushes latent overlay activity over the amplification threshold. The fact that visual response goes different directions across subtypes is not a prediction failure — it is the most informative possible outcome, because the scientifically critical prediction is that therapeutic outcomes (MEQ30, belief revision, symptom reduction) should be independent of VR scores across all subtypes. If deep-congenital aphantasics achieve equivalent therapeutic benefit with zero visuals, acquired aphantasics achieve it with some visuals, and typical imagers achieve it with full visuals, this cleanly dissociates the overlay (variable) from the substrate (shared therapeutic mechanism).
-
Ketamine dissociative effects should be fully present regardless of imagery status or subtype, since NMDA blockade disrupts associative binding across all modalities — operating at the substrate level, not the overlay.
-
Guided interoception should show equal or superior outcomes to guided imagery for high-object-vividness PTSD patients whose overlay is actively weaponized against them. For low-vividness patients, comparable outcomes would suggest the overlay was never the necessary therapeutic pathway. For aphantasic patients with somatic trauma, guided interoception with SE-style titration should show efficacy but require more sessions and more skilled navigation of somatic trigger territory.
-
Mystical experience (MEQ30) should be achievable by aphantasic participants across all induction methods (psilocybin, breathwork, meditation) despite absent visual phenomena — because mystical experience, per the mechanistic account, arises from interoceptive integration and boundary dissolution at the substrate level, not from visual content in the overlay. If aphantasic participants can report the same phenomenology (unity, transcendence, ineffability, positive mood) without visual rendering, this confirms the first-principles account.
-
For developmental recovery: addressing both educational invalidation (psychoeducation about the substrate) and trauma-driven distrust (co-regulation, re-engagement with somatic knowing) should produce greater recovery than addressing either alone.
-
For educational assessment: VVIQ screening in "gifted underperformers" should reveal overrepresentation of aphantasia/hypophantasia relative to age-matched peers.
Conclusion: what removing the overlay reveals about the system it covers¶
The simulation-lucid phenotype—complete aphantasia with preserved interoceptive-proprioceptive processing—is not a different system. It is the same system that every mammalian brain runs on, made visible by the absence of the rendering overlay that normally obscures it. Much as albinism reveals the melanin synthesis pathway that exists in all skin by removing the pigmentation that hides it, aphantasia reveals the interoceptive-somatic substrate that operates in every brain by removing the imagery overlay that normally dominates conscious report.
This reframing carries consequences in every direction the framework touches.
For psychedelic research, it means that aphantasic participants are not edge cases to be excluded but essential collaborators whose neurology provides a natural dissection — the overlay is absent, so whatever therapeutic benefit they achieve must be operating through the shared substrate. The prediction that visual response will vary by subtype while therapeutic outcome converges across subtypes is not just testable but, if confirmed, would resolve a debate the field has sustained for decades.
For clinical practice, it means that guided interoception is not an accommodation for a rare condition but a formalization of what the world's oldest contemplative traditions already discovered: that attending to the substrate directly, beneath the overlay, produces deeper and more reliable therapeutic and contemplative outcomes — for everyone, including those with full imagery capacity. The imagery overlay is not the tool. It is the screen that shows you what the tool is doing. The tool is the interoceptive substrate. The contemplative traditions knew this. The SE and Focusing literatures know this. What is missing is the institutional recognition: a named clinical framework with the same status as guided imagery.
For understanding mystical experience, the first-principles account establishes that these experiences are real neurological events — interoceptive integration achieving maximum coherence while boundary-maintaining systems go offline — happening locally, through identifiable neuroanatomy, producing lasting measurable changes. This validates the phenomenology and the contemplative methodology while grounding both in the hardware. The attribution to external agency is the narrative cortex constructing an after-the-fact explanation for an event that occurred while the narrative system was offline. The experience is real. The mechanism is local.
For education, it means that some proportion of students whose cognition operates primarily through the substrate are being systematically invalidated by assessment practices that require demonstration of overlay-based processing steps — and that this invalidation is invisible because the overlay is treated as the default cognitive architecture rather than one layer of a deeper system.
For neurodivergence, it means that conditions involving different relationships between overlay and substrate — aphantasia (absent overlay), hyperphantasia (dominant overlay), autism (different precision weighting across layers), mirror-touch synesthesia (substrate-level social processing crossing into consciousness) — are not disorders of a single system but variations in the relationship between layers of one integrated system.
The field possesses the conceptual tools, the measurement instruments, and the participant population to test every prediction this framework generates. What it requires is the recognition that the ~1% of humanity who lack the imagery overlay are not missing something. They are showing us — all of us — what is underneath.
Methodology: AI-Augmented Autoethnographic Synthesis¶
This document was produced through a methodology we term AI-augmented autoethnographic synthesis — a collaborative research process in which a human researcher's lived experience serves as primary data, an AI system performs literature retrieval and prose synthesis, and the theoretical framework emerges through iterative conversational refinement.
What each contributor provided¶
The human researcher (Steven Kirkland) provided: first-person phenomenological data from living with complete aphantasia, anauralia, and mirror-touch synesthesia — including observations that generated novel hypotheses (e.g., the proprioceptive spatial construction observation, the somatic confirmation channel, the topology of trauma contamination across overlay and substrate); cross-domain pattern recognition connecting disparate literatures (EMDR hardware engineering, distributed synchronization, neuroscience, contemplative traditions, educational assessment); and critical evaluation that identified theoretical gaps and stance errors requiring substantive correction throughout the research process.
The AI system (Claude, Anthropic) provided: literature retrieval via web search, reference identification and DOI verification, synthesis of findings into prose, structural organization of the framework, and generation of testable predictions from the theoretical commitments. The AI also failed to draw connections that were implicit in the assembled evidence — most notably the first-principles account of mystical experience mechanism, which required the human researcher to identify and prompt.
How the process worked¶
The framework emerged through iterative conversational sessions in which the human researcher would identify a direction, observation, or challenge; the AI system would search the literature, draft sections, and propose implications; and the human researcher would evaluate critically against lived experience and theoretical coherence, redirecting when the output was inaccurate, overstated, or missed connections. Experiential data served as both hypothesis generator and reality check: when the document's claims did not match the researcher's actual neurology, this was treated as evidence that the theory needed correction, not that the experience was anomalous.
Limitations¶
Literature retrieval was performed in two phases. Initial retrieval used web search during conversational sessions. Subsequent structured searches were conducted via web-based PubMed access across eight key topic intersections (aphantasia-psychedelics, aphantasia-interoception, imagery-PTSD, body scan-interoception, somatic experiencing RCTs, aphantasia-alexithymia, aphantasia-trauma, and anterior insular cortex-mystical experience). These structured searches substantially improved coverage but remain not PRISMA-compliant: they were conducted through web search tools targeting PubMed rather than through formal Boolean queries with MeSH terms; PsycINFO, Web of Science, and Cochrane databases were not searched; search strings were not pre-registered; and no duplicate screening, quality assessment, or risk-of-bias evaluation was performed. Key references were verified by DOI where possible, but the full reference list has not been comprehensively audited against primary sources.
Autoethnographic data — the phenomenological observations from the primary researcher — constitutes qualitative evidence from a single individual (n=1). While autoethnography is an established research methodology and the observations generated testable hypotheses grounded in existing literature, they require empirical validation across larger aphantasic populations before any clinical or theoretical claims can be generalized.
AI synthesis introduces the possibility of subtle mischaracterization of cited sources, hallucinated claims, or overstated confidence in the strength of evidence. While critical review by the human researcher mitigated this throughout the process, readers should verify key claims against primary sources, particularly where specific statistical findings or mechanistic claims are attributed to individual studies.
The iterative process means the document reflects the state of the framework at a specific point in its development. Earlier versions contained theoretical errors (treating interoception as a separate system rather than the universal substrate, overstating body-based immunity to trauma contamination, issuing blanket psilocybin predictions that contradicted the cited evidence) that were identified through critical review and corrected. The current version is more honest than its predecessors, but the same iterative process should be expected to continue as the framework encounters further empirical evidence and critical scrutiny.
Why this methodology matters¶
AI-augmented autoethnographic synthesis occupies an unusual methodological position. It combines the irreplaceable epistemological value of first-person phenomenological data — particularly from neurological variants whose subjective experience cannot be accessed through third-person methods alone — with computational literature synthesis at a scale and speed that would be difficult for an independent researcher without institutional affiliation or database access. The result is a theoretical framework that could not have been produced by either contributor alone: the human researcher lacked the literature access and synthesis capacity; the AI system lacked the experiential data, the cross-domain pattern recognition, and the critical judgment to identify when its own output was wrong.
This methodology is not a substitute for formal empirical research. It is a hypothesis-generation and framework-construction tool that produces testable predictions requiring validation through the standard methods of experimental psychology and cognitive neuroscience. Every prediction in Part VII is designed to be falsifiable through studies that do not require this methodology to execute.
Key References¶
Aphantasia neuroscience: Zeman et al. (2010, 2015, 2024 Trends Cogn Sci); Pearson (2019 Nat Rev Neurosci); Keogh, Bergmann & Pearson (2020); Koenig-Robert & Pearson (2019, 2021); Milton et al. (2021); Liu & Bartolomeo (2023, 7T fMRI); Liu (2025/2026, integration model); Chang et al. (2025 Curr Biol, DOI: 10.1016/j.cub.2024.12.012); Scholz, Monzel & Liu (2025, Curr Biol response); Dawes, Keogh & Pearson (2024); Hinwar & Lambert (2021, anauralia); Bouyer & Arnold (2024, deep aphantasia); Balaban & Ullman (2025 Trends Cogn Sci); Koenig-Robert et al. (2025 Cortex)
Imagery neuroscience: Dijkstra et al. (2017); Winlove et al. (2018, meta-analysis); Kay et al. (2022, pupillometry); Wicken et al. (2021, SCR); Keogh & Pearson (2018, 2024, binocular rivalry)
Interoceptive hierarchy: Craig (2002, 2003, 2009); Silvanto & Nagai (2025a, Brain Topography; 2025b, Front Psychol, predictive coding account, DOI: 10.3389/fpsyg.2025.1564251); Nagai et al. (2025, n=468); Monzel et al. (2025, imagery-interoception-mental health mediation, PMID: 41539358)
Somatic markers: Damasio (1991, 1994, 1996); Bechara et al. (1997, Iowa Gambling Task); Monzel, Karneboge & Reuter (2024, aphantasia/alexithymia overlap, Biomarkers in Neuropsychiatry, DOI: 10.1016/j.bionps.2024.100106)
Subcortical emotion: Panksepp (1998, 2010); Merker (2007, hydranencephaly); Shewmon et al. (1999); Ben-Ami Bartal et al. (2011, 2021, rat empathy); Van Overwalle (2024, cerebellum Nat Rev Neurosci)
Psychedelic mechanisms: Carhart-Harris & Friston (2019, REBUS); Carhart-Harris et al. (2012, 2017); Gattuso et al. (2023); Kometer et al. (2013); Scheidegger et al. (2012); Marguilho et al. (2023); Stoliker et al. (2024, Mol Psychiatry, psychedelic visual imagery mechanisms, DOI: 10.1038/s41380-024-02818-9); Siegel et al. (2024, Nature, psilocybin desynchronization, DOI: 10.1038/s41586-024-07624-5); Brudner et al. (2025, J Psychopharmacol, mystical experience predicts PAP outcomes, DOI: 10.1177/02698811251346697); 2025 REBAS study
Psychedelics & aphantasia: Dos Santos et al. (2018); Luke (2018, 1,000 DMT sessions); Rebecchi (2023)
Ketamine: Meuwese et al. (2013); Wiegand et al. (2023); Neymotin et al. (2011); Grent-'t-Jong et al. (2018)
Imagery as PTSD risk factor: Kosslyn (2005, Dev Psychopathol); Morina, Leibold & Ehring (2013, J Behav Ther Exp Psychiatry, DOI: 10.1016/j.jbtep.2012.11.004); Bryant & Harvey (1996); Yeung et al. (2025, Clin Psychol Sci, DOI: 10.1177/21677026251315118); Clark & Mackay (2015, Front Psychiatry)
Safe-place contamination: Kantor et al. (2020, JMIR Mental Health)
Somatic flashbacks/body memories: Whalley et al. (2021, Eur J Psychotraumatol); Terpou et al. (2022, Front Neurosci, brain-body disconnect)
Polyvagal/trauma: Porges (1995, 2001, 2007, 2022, 2025); Grossman (2023, critique); Monteiro et al. (2018); Van der Kolk (2014); Murphy et al. (2022); Levin et al. (2024); Krediet et al. (2024); Modlin et al. (2025)
NTS convergence: McDougall & Bhatt (2009)
Breathwork/vestibular: Lopez (2013); 2025 Commun Psychol breathwork study; 2025 PLOS ONE breathwork study; Gerritsen & Band (2018); Bremner et al. (2021, tVNS)
Body-based contemplative pathways: Fischer, Messner & Pollatos (2017, Front Hum Neurosci, DOI: 10.3389/fnhum.2017.00452); Kok & Singer (2017, Mindfulness); Ehmann et al. (2025, meta-analysis); Kabat-Zinn (MBSR)
Body-based therapy modalities: Gendlin (1978, 1981, Focusing/EXP); Price (MABT); Winhall (2021, FSPM); Levine/Payne et al. (2015, Somatic Experiencing); Brom et al. (2017, SE RCT); Ogden (Sensorimotor Psychotherapy)
Aphantasia clinical adaptation: Mawtus, Renwick, Thomas & Reeder (2024, Collabra: Psychology, DOI: 10.1525/collabra.127416); Reeder & Mawtus (2023, 2025, Aphantasia Network)
Ventral/dorsal dissociation: Farah, Hammond, Levine & Calvanio (1988, Cogn Psychol); Bainbridge, Pounder, Eardley & Baker (2021, Cortex, drawing double dissociation); OSIQ (Keogh & Pearson, 2018; Dawes et al., 2020); Reeder et al. (2024, Cognition, strategy use); Phillips (2025, Trends Cogn Sci, spared spatial imagery)
Proprioceptive spatial construction: Rock & Victor (1964); Ernst & Banks (2002, Nature, Bayesian multisensory integration); Wasaka & Kakigi (2012, NeuroImage, visual suppression of SI); Hecht et al. (2008); Afonso et al. (2010, Mem Cognit); Graziano (1999, Neuron, hand-anchored bimodal neurons); Lazar et al. (2005, somatosensory cortex thickness in meditators); Blouin et al. (2018, proprioceptive deprivation)
Childhood invalidation: Krause, Mendelson & Lynch (2003); Linehan (1993); Greenes (1981); ERIC (2002); Strozzi Institute
Educational assessment: Kay, Keogh & Pearson (2024, mental rotation); Milton et al. (2021, IQ); Wen et al. (2017, Raven's matrices)
Mirror-touch synesthesia: Banissy et al. (2009, 2011); Blakemore et al. (2005); Bolognini et al. (2013); Ward & Banissy (2015); Dance et al. (2021, 2023); Baron-Cohen et al. (2016)
Neurodivergence: Dunbar (1998, 2024); Van de Cruys et al. (2014, HIPPEA); Kohls et al. (2018); Milton (2012, 2022, double empathy); Crompton et al. (2020)
Mystical experience: Griffiths et al. (2006, 2008, 2011, 2016, 2018); Newberg; Cristofori et al. (2016, TBI/mysticism); Brewer et al. (2011); Picard (2023, ecstatic epilepsy/anterior insular cortex, PMC 10513764)
Face processing: Kanwisher et al. (1997); Wang et al. (2023); McFadyen et al. (2019); Monzel et al. (2023); Dance et al. (2023)
5D-ASC/MEQ30: Dittrich (1998); Barrett et al. (2015); MacLean et al. (2012)
This document is part of the mlehaptics open-source assistive technology ecosystem. Published openly because the interoceptive-somatic substrate operates in every brain — aphantasia simply makes it visible. Understanding what the removal of the imagery overlay reveals about the system it covers has implications for everyone: for trauma survivors whose overlay has been weaponized, for contemplative practitioners seeking the substrate their traditions already point to, for educators who unknowingly invalidate students processing through channels they cannot see, and for researchers who need testable hypotheses about what consciousness actually requires.