The multimodal Ganzfeld-induced altered state of consciousness induces decreased thalamo-cortical coupling.
Timo Torsten Schmidt, Nisha Jagannathan, Michal Ljubljanac, Ann Xavier, Till Nierhaus
Scientific Reports October 29, 2020 DOI: 10.1038/s41598-020-75019-3 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 19 |
| Population | Human participants |
| Intervention | Ganzfeld stimulation |
| Duration | Compared to pre- and post-resting-state scans |
| Topics | Altered states of consciousness |
| Key findings | Ganzfeld stimulation induces a progressive decoupling of the thalamus from the cortex and increased eigenvector centrality in core DMN regions, opposite to psychedelic-induced effects. |
Abstract
Different pharmacologic agents have been used to investigate the neuronal underpinnings of alterations in consciousness states, such as psychedelic substances. Special attention has been drawn to the role of thalamic filtering of cortical input. Here, we investigate the neuronal mechanisms underlying an altered state of consciousness (ASC) induced by a non-pharmacological procedure. During fMRI scanning, N = 19 human participants were exposed to multimodal Ganzfeld stimulation, a technique of perceptual deprivation where participants are exposed to intense, unstructured, homogenous visual and auditory stimulation. Compared to pre- and post-resting-state scans, the Ganzfeld data displayed a progressive decoupling of the thalamus from the cortex. Furthermore, the Ganzfeld-induced ASC was characterized by increased eigenvector centrality in core regions of the default mode network (DMN). Together, these findings can be interpreted as an imbalance of sensory bottom-up signaling and internally-generated top-down signaling. This imbalance is antithetical to psychedelic-induced ASCs, where increased thalamo-cortical coupling and reduced DMN activity were observed.