Visual hallucinations originating in the retinofugal pathway under clinical and psychedelic conditions.

Psychedelics like LSD and psilocybin alter perception by activating serotonin receptors in cortical and subcortical brain regions, often causing visual disturbances or hallucinations. While current theories focus on disrupted communication between these brain areas, rare conditions like Charles Bonnet syndrome suggest the retinofugal pathway may also play a key role. Interneurons in the retina called amacrine cells could be the first site of psychedelic modulation, disrupting how visual information is hierarchically processed. This paper presents a new theory of psychedelic modulation in the retinofugal pathway, drawing parallels with clinical conditions to explain visual perceptual changes.

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Abstract

Psychedelics like LSD (Lysergic acid diethylamide) and psilocybin are known to modulate perceptual modalities due to the activation of mostly serotonin receptors in specific cortical (e.g., visual cortex) and subcortical (e.g., thalamus) regions of the brain. In the visual domain, these psychedelic modulations often result in peculiar disturbances of viewed objects and light and sometimes even in hallucinations of non-existent environments, objects, and creatures. Although the underlying processes are poorly understood, research conducted over the past twenty years on the subjective experience of psychedelics details theories that attempt to explain these perceptual alterations due to a disruption of communication between cortical and subcortical regions. However, rare medical conditions in the visual system like Charles Bonnet syndrome that cause perceptual distortions may shed new light on the additional importance of the retinofugal pathway in psychedelic subjective experiences. Interneurons in the retina called amacrine cells could be the first site of visual psychedelic modulation and aid in disrupting the hierarchical structure of how humans perceive visual information. This paper presents an understanding of how the retinofugal pathway communicates and modulates visual information in psychedelic and clinical conditions. Therefore, we elucidate a new theory of psychedelic modulation in the retinofugal pathway.