Neurosensory Research Foundation

According to an MIT news article published May 21, 2026, neuroscientists have identified key rules that neurons in the visual cortex follow to process what we see. By imaging both responsive and non-responsive neurons in mice, the team found that:

1. Distance matters: On responsive neurons, spine activity correlates more strongly with the cell body when spines are closer to it.
2. Local clustering: Spines within 5 microns act in concert, while those just beyond are less likely to join in—possibly sharpening responses.
3. Dendrite type: Apical dendrites on responsive neurons have more visually responsive spines than those on non-responsive neurons, even though basal dendrites generally receive more raw visual input.
4. Orientation selectivity is key: How selective a spine is to a grating’s orientation is the single most important factor predicting its correlation with the cell body’s response.

The findings, published in iScience, help establish a baseline for studying genetic mutations affecting vision and could inform computational models of neural integration.

The rules neurons follow to make sense of what we see Neuroscientists at The Picower Institute for Learning and Memory at MIT reveal how neurons that perform visual processing bring order to the input they receive via thousands of synapses to get their job done.

The article is a case-based discussion centered on a rare visual perceptual phenomenon associated with Hallucinogen Persisting Perception Disorder (HPPD)—a condition in which individuals continue to experience persistent perceptual distortions after hallucinogen use.

Key case features

* The patient experienced ongoing visual distortions described as “distorted cartoonish” or unreal imagery in the environment.
* These perceptual changes persisted beyond acute intoxication and were clinically significant enough to impair normal perception.
* The presentation aligns with HPPD-type visual phenomena, which can include:
* Geometric hallucinations
* Afterimages (palinopsia)
* Visual snow-like effects
* Altered color/shape perception

Clinical framing

* The authors highlight that such symptoms can be misinterpreted as primary psychotic disorders, but in HPPD they are typically:
* Preserved insight (patient often knows perception is altered)
* Strong temporal association with hallucinogen exposure
* Differential diagnosis includes:
* Psychotic disorders (e.g., schizophrenia-spectrum conditions)
* Neurologic visual disturbances (migraine aura, occipital lobe pathology)
* Medication-induced perceptual changes

Clinical implications

* The report emphasizes:
* The importance of recognizing HPPD as a distinct diagnosis
* Avoiding unnecessary antipsychotic labeling when insight is intact
* Considering careful substance-use history in patients with unusual visual symptoms
* Treatment options remain limited, but may include:
* Symptom-targeted pharmacotherapy (often off-label)
* Psychoeducation and reassurance
* Avoidance of triggering substances

Bottom line

The article documents a rare but illustrative case of persistent visual distortions consistent with HPPD, and underscores the diagnostic challenge of distinguishing it from primary psychotic or neurologic disorders.

Distorted Cartoonish Images in the Environment: A Unique Visual Phenomenon in Hallucinogen Persisting Perception Disorder | American Journal of Psychiatry Residents' Journal PsychiatryOnline.org is the platform for all American Psychiatric Association Publishing journals, DSM, and bestselling textbooks, as well as APA Practice Guidelines, and continuing medical education.

Here’s the connection:

* The new work argues that color perception follows a precise internal geometric structure created by neural processing.
* HPPD symptoms — visual snow, trailing, halos, intensified colors, afterimages, pattern glare, derealization — suggest that this internal visual processing geometry becomes dysregulated.
* In HPPD, the brain may fail to properly stabilize or suppress sensory information, causing perception to become overly “raw,” noisy, or unstable.

One possible implication:
normal brains continuously “normalize” visual input so colors, motion, brightness, and contrast remain coherent. HPPD may involve partial breakdown of those normalization systems.

Examples:

* Brightness changes may distort color perception excessively.
* Contrast edges may become hyper-salient.
* Afterimages may persist because inhibitory networks fail to dampen visual persistence.
* Visual snow may reflect spontaneous cortical noise overwhelming filtering systems.

This overlaps with current theories involving:

* thalamocortical dysrhythmia
* impaired GABAergic inhibition
* visual cortex hyperexcitability
* dysfunctional predictive coding/network filtering

Researchers studying disorders like Visual Snow Syndrome and HPPD increasingly think the problem is not isolated to one brain region, but to distributed visual-processing networks. That aligns with this new color-geometry work because it also treats perception as an emergent property of coordinated neural computations rather than simple retinal input.

The study could indirectly help future HPPD research in a few ways:

* Better mathematical models of subjective perception
* More precise measurement of perceptual distortions
* Improved computational models of visual cortical processing
* Potential biomarkers for altered perceptual states

But it is important to separate:

* fundamental perception theory
from
* therapeutic intervention research.

This paper does not provide a treatment pathway for HPPD, nor does it directly explain why hallucinogens can trigger persistent perceptual changes.

The more clinically relevant overlap is with modern network neuroscience approaches — especially work by researchers studying:

* cortical oscillations
* sensory gating
* thalamocortical loops
* predictive coding failures
* functional connectivity abnormalities

That is why efforts like neuromodulation, TMS, neurofeedback, and network-targeted therapies are attracting attention in HPPD and VSS research.

Scientists Solve 100-Year-Old Schrödinger Mystery About Color Perception Scientists have finally cracked the hidden geometry behind how humans perceive color.

Decoding Complexity: Targeting Individual Pathways in the Cortex - Neuroscience News How do brain regions communicate? Researchers introduce a new optogenetic method to target long-distance circuits in marmosets. Discover how this "light switch" for brain highways is revealing the secrets of the cerebral cortex.

Don’t believe for a single second HPPD isn’t seen in clinical trials. It’s more common than people realize and reason why it must be researched!

From the Psychiatry community on Reddit: First case of HPPD (hallucinogen persisting perception disorder) reported in a clinical trial of psilocybin Posted by speedledum - 185 votes and 69 comments

New research has found that magnetic pulses are just as effective as electricity at treating severe depression, but with far fewer cognitive side effects.

Read our coverage of the study via the link in the comments.

This paper reviews flashbacks and Hallucinogen Persisting Perception Disorder (HPPD) as complications of classic psychedelic use, focusing on how they are defined, classified, and managed clinically. It explains that post-psychedelic perceptual disturbances range from benign, transient flashbacks to more severe, persistent syndromes (HPPD), which can involve ongoing visual distortions, depersonalization, and significant distress or impairment. The authors highlight that these phenomena are heterogeneous and poorly understood, with unclear neurobiological mechanisms and inconsistent diagnostic criteria, making them difficult to study and treat. The review also discusses potential risk factors (such as prior psychiatric vulnerability and substance use patterns) and outlines current management approaches, which are largely symptom-based and not standardized, emphasizing the need for better classification systems and more rigorous clinical research.
-Here’s the problem… NOBODY IS DOING ANY RESEARCH INTO HPPD!

Flashbacks, Hallucinogen Persisting Perception Disorder (HPPD), and Reactivations Following the Use of Classic Psychedelics: Classification and Therapeutic Management - PubMed Among the complications associated with the use of classic psychedelics, flashbacks, hallucinogen persisting perception disorder (HPPD) and reactivations are most specifically linked to their use. These three phenomena share the occurrence of perceptual disturbances resembling those experienced unde...

HPPD happens and it happens more than we are all lead to believe.
This randomized clinical trial (EPISODE, phase 2b) evaluated the efficacy and safety of psilocybin-assisted therapy in 144 adults with treatment-resistant depression. Participants received varying doses of psilocybin (including a 25 mg dose) combined with psychotherapy and were compared to an active placebo. The primary outcome—achieving at least a 50% reduction in depression severity by week 6—was not statistically significant for the 25 mg psilocybin group versus placebo, although response rates were numerically higher (17.0% vs 10.6%). Secondary analyses suggested clinically meaningful reductions in depressive symptoms, indicating potential therapeutic benefit despite the inconclusive primary endpoint. Safety findings showed that psilocybin was generally tolerated, but acute adverse effects occurred, including a small increase in suicidal ideation on dosing days and rare serious events (including one case of hallucinogen persisting perception disorder). Overall, the study concludes that psilocybin shows promise but remains inconclusive, warranting further research.

Efficacy and Safety of Psilocybin in Treatment-Resistant Major Depression: The EPISODE Randomized Clinical Trial - PubMed ClinicalTrials.gov Identifier: NCT04670081.

President Trump signed an executive order directing the Food and Drug Administration to support research and potentially approve psychedelic drugs, which he hopes will help Americans struggling with mental illness.

President Trump signs executive order encouraging research on psychedelic drugs President Donald Trump signed an executive order Saturday morning directing the Food and Drug Administration to support research and potentially approve psychedelic drugs.