Rapid effects of tryptamine psychedelics on perceptual distortions and early visual cortical population receptive fields.
Marta Lapo Pais, Marta Teixeira, Carla Soares, Gisela Lima, Patrícia Rijo, Célia Cabral, Miguel Castelo-Branco
Neuroimage August 15, 2024 DOI: 10.1016/j.neuroimage.2024.120718 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Within-subject experimental study Peer reviewed |
|---|---|
| Population | Human participants |
| Intervention | inhaled DMT |
| Topics | Serotonin |
| Keywords | 5-ht2a receptors Population responses Visual cortex Visual hallucinations Psychedelics hallucinogens Entheogens Psychedelic drugs Neuroscience brain science Neural activity Neurobiology Visual perception vision Sight Visual processing Visual system DMT Dim |
| Citations | 8 |
| Key findings | Inhaled DMT significantly increases mean population receptive field sizes in the peripheral visual field of V1 compared to control, which may explain psychedelic-induced perceptual distortions. |
Abstract
N, N-dimethyltryptamine (DMT) is a psychedelic tryptamine acting on 5-HT2A serotonin receptors, which is associated with intense visual hallucinatory phenomena and perceptual changes such as distortions in visual space. The neural underpinnings of these effects remain unknown. We hypothesised that changes in population receptive field (pRF) properties in the primary visual cortex (V1) might underlie visual perceptual experience. We tested this hypothesis using magnetic resonance imaging (MRI) in a within-subject design. We used a technique called pRF mapping, which measures neural population visual response properties and retinotopic maps in early visual areas. We show that in the presence of visual effects, as documented by the Hallucinogen Rating Scale (HRS), the mean pRF sizes in V1 significantly increase in the peripheral visual field for active condition (inhaled DMT) compared to the control. Eye and head movement differences were absent across conditions. This evidence for short-term effects of DMT in pRF may explain perceptual distortions induced by psychedelics such as field blurring, tunnel vision (peripheral vision becoming blurred while central vision remains sharp) and the enlargement of nearby visual space, particularly at the visual locations surrounding the fovea. Our findings are also consistent with a mechanistic framework whereby gain control of ongoing and evoked activity in the visual cortex is controlled by activation of 5-HT2A receptors.
Comparable studies
Other experimental studies on serotonin, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Psilocybin induces schizophrenia-like psychosis in humans via a serotonin-2 agonist action Healthy human volunteers | 1998 | Experimental study | |
| Amphetamine-type central nervous system stimulants release norepinephrine more potently than they release dopamine and serotonin | 2000 | Experimental study | |
| Methylenedioxyamphetamine (MDA) and methylenedioxymethamphetamine (MDMA) cause selective ablation of serotonergic axon terminals in forebrain: immunocytochemical evidence for neurotoxicity Rat brain | 1988 | Experimental study | |
| The molecular mechanism of "ecstasy" [3,4-methylenedioxy-methamphetamine (MDMA)]: serotonin transporters are targets for MDMA-induced serotonin release. Human platelet plasma membrane vesicles and bovine adrenal chromaffin granule membrane... | 1992 | Laboratory study | |
| 5-HT2AReceptor-Mediated Regulation of Brain-Derived Neurotrophic Factor mRNA in the Hippocampus and the Neocortex Rat brain | 1997 | Experimental study |
Citations in the library
Cited by 6
- Increased functional connectivity between brain regions involved in social cognition, emotion and affective-value in psychedelic states induced by N,N-Dimethyltryptamine (DMT). Frontiers in Pharmacology 2024
- Psychedelic experiences elicited by serotonergic psychedelics: Molecular mechanisms and functional connectivity changes in the brain Neuroscience & Biobehavioral Reviews December 16, 2025
- Psilocybin alters visual contextual computations. Nature Communications November 21, 2025
- Psilocybin prevents habituation to familiar stimuli and preserves sensitivity to sound following repeated stimulation in mouse primary auditory cortex bioRxiv (Cold Spring Harbor Laboratory) September 30, 2024
- Inhaled N, N-dimethyltryptamine diminishes connectivity between the ventral tegmental area and the nucleus accumbens: relevance to pathologies of mesolimbic and mesocortical pathways Scientific Reports December 12, 2025
and 1 more in the library
Cites 15
- Human hallucinogen research: guidelines for safety. Journal of Psychopharmacology July 1, 2008
- The Standardized Psychometric Assessment of Altered States of Consciousness (ASCs) in Humans Pharmacopsychiatry July 1, 1998
- Dose-Response Study of N,N-Dimethyltryptamine in Humans Archives of General Psychiatry February 1, 1994
- Receptor interaction profiles of novel psychoactive tryptamines compared with classic hallucinogens. European Neuropsychopharmacology May 20, 2016
- Neuropharmacology of N,N-dimethyltryptamine Brain Research Bulletin April 30, 2016
and 10 more in the library