Altered Brain Connectivity and Network Topological Organization in a Non-ordinary State of Consciousness Induced by Hypnosis
Rajanikant Panda, Audrey Vanhaudenhuyse, Andrea Piarulli, Jitka Annen, Athena Demertzi, Naji Alnagger, Srivas Chennu, Steven Laureys, Marie-Elisabeth Faymonville, Olivia Gosseries
Journal of Cognitive Neuroscience January 1, 2023 DOI: 10.1162/jocn_a_02019 via OpenAlex
Summary
During hypnosis, brain connectivity changes in ways that suggest more efficient cognitive processing and less mind-wandering. In nine healthy participants, hypnosis increased delta-wave connections between frontal brain regions and between frontal and parietal regions. It decreased alpha and beta-2 connections among frontal, parietal, and midline areas. Network analysis showed greater segregation of short-range connections in delta and alpha bands and greater integration of long-range connections in beta-2 bands. Frontal and right parietal electrodes became central hubs. These altered dynamics may reflect a modified balance between internal and external awareness networks.
Study at a glance
| Characteristics | Within-subjects experimental study Peer reviewed |
|---|---|
| Sample size | 9 |
| Population | Healthy participants |
| Keywords | Hypnosis Consciousness Neuroscience Cognitive science Altered state |
| Citations | 15 |
| Key finding | Hypnosis increased delta connectivity between frontal and parietal regions, decreased alpha and beta-2 connectivity in frontal-parietal and midline networks, and increased network segregation and integration, suggesting efficient cognitive processing and reduced mind-wandering. |
Abstract
Hypnosis has been shown to be of clinical utility; however, its underlying neural mechanisms remain unclear. This study aims to investigate altered brain dynamics during the non-ordinary state of consciousness induced by hypnosis. We studied high-density EEG in 9 healthy participants during eyes-closed wakefulness and during hypnosis, induced by a muscle relaxation and eyes fixation procedure. Using hypotheses based on internal and external awareness brain networks, we assessed region-wise brain connectivity between six ROIs (right and left frontal, right and left parietal, upper and lower midline regions) at the scalp level and compared across conditions. Data-driven, graph-theory analyses were also carried out to characterize brain network topology in terms of brain network segregation and integration. During hypnosis, we observed (1) increased delta connectivity between left and right frontal, as well as between right frontal and parietal regions; (2) decreased connectivity for alpha (between right frontal and parietal and between upper and lower midline regions) and beta-2 bands (between upper midline and right frontal, frontal and parietal, also between upper and lower midline regions); and (3) increased network segregation (short-range connections) in delta and alpha bands, and increased integration (long-range connections) in beta-2 band. This higher network integration and segregation was measured bilaterally in frontal and right parietal electrodes, which were identified as central hub regions during hypnosis. This modified connectivity and increased network integration-segregation properties suggest a modification of the internal and external awareness brain networks that may reflect efficient cognitive-processing and lower incidences of mind-wandering during hypnosis.