Thalamocortical interactions reflecting the intensity of flicker light-induced visual hallucinatory phenomena.
Ioanna Amaya, Till Nierhaus, Timo T Schmidt
Network Neuroscience 2025 DOI: 10.1162/netn_a_00417 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Controlled experimental study Peer reviewed |
|---|---|
| Population | Healthy participants |
| Topics | Altered states of consciousness |
| Keywords | Flicker light stimulation Functional connectivity Thalamic nuclei Thalamocortical connectivity Visual hallucinations |
| Key findings | Rhythmic flicker light stimulation selectively increases connectivity between ventroanterior thalamic nuclei and higher order visual cortices, and this connectivity is positively associated with the subjective intensity of visual hallucinations. |
Abstract
Aberrant thalamocortical connectivity occurs together with visual hallucinations in various pathologies and drug-induced states, highlighting the need to better understand how thalamocortical interactions may contribute to hallucinatory phenomena. Flicker light stimulation (FLS) at 10-Hz reliably and selectively induces transient visual hallucinations in healthy participants. Arrhythmic flicker elicits fewer hallucinatory effects while delivering equal amounts of visual stimulation, together facilitating a well-controlled experimental setup to investigate the neural correlates of visual hallucinations driven by flicker rhythmicity. Using rhythmic and arrhythmic FLS during fMRI scanning, we found that rhythmic FLS elicited stronger activation in higher order visual cortices compared with arrhythmic control. Consistently, we found that rhythmic flicker selectively increased connectivity between ventroanterior thalamic nuclei and higher order visual cortices, which was also positively associated with the subjective intensity of visual hallucinatory effects. As these thalamic and cortical areas do not receive primary visual inputs, it suggests that the thalamocortical connectivity changes relate to a higher order function of the thalamus, such as in the coordination of cortical activity. In sum, we present novel evidence for the role of specific thalamocortical interactions with ventroanterior nuclei within visual hallucinatory experiences. Importantly, this can inform future clinical research into the mechanistic underpinnings of pathologic hallucinations.
Comparable studies
Other experimental studies on altered states of consciousness, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| The Standardized Psychometric Assessment of Altered States of Consciousness (ASCs) in Humans Healthy subjects in six countries | 1998 | Experimental and field study | n = 1,133 |
| TMS-EEG and resting-state EEG applied to altered states of consciousness: oscillations, complexity, and phenomenology. | 2023 | Experimental study | |
| A Test of the Psychedelic Model of Altered States of Consciousness | 1976 | Experimental study with comparison groups | |
| Neural Correlates of Non-ordinary States of Consciousness in Pranayama Practitioners: The Role of Slow Nasal Breathing Experienced meditators | 2022 | Within-subjects comparison | n = 12 |
| Increased spontaneous EEG signal diversity during stroboscopically-induced altered states of consciousness Healthy adults | 2019 | Experimental study |
Citations in the library
Cited by 2
- Stroboscopic light stimulation as a controllable probe of the psilocybin state: a mechanistic framework and a falsifiable prediction Frontiers in Pharmacology September 30, 2026
- Cellular mechanisms of serotonergic psychedelics - apical hypercontextualisation. Neuroscience & Biobehavioral Reviews July 1, 2026
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