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Ph. D. Thesis Colloquium of Mr. Pradeep K. G.: 11 am Monday, 15 May: EEG correlates of non-ordinary states of consciousness and slow-paced breathing
May 15, 2023 @ 4:30 PM IST
Title: EEG correlates of non-ordinary states of consciousness and slow-paced breathing
Name of the student: Pradeep Kumar G
Advisor: Prof. A. G. Ramakrishnan
Date and Time: 15 May 2023 (Monday) 11:00 AM
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TITLE: EEG correlates of non-ordinary states of consciousness and slow-paced breathing
Studies on the non-ordinary states of consciousness (NSCs) induced by meditation, hypnosis, and trance are gaining visibility due to their potential efficacy in treating various clinical conditions. Slow-paced breathing at six cycles per minute (cpm) has been labelled as coherent breathing since it has been suggested to induce synchronous resonance frequency in various physiological signals. These self-regulatory or guided processes are practiced primarily to reduce stress and manage emotions and mental health. However, the underlying mechanisms for the health benefits of these practices still need to be fully understood. Electroencephalography (EEG), a non-invasive electrophysiological tool to investigate brain’s electrical activity, is used to study the changes in brain dynamics during different NSCs.
Significant contributions of the thesis:
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Changes in EEG coupling during eyes-open meditation.
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The interdependencies between brain signals clustered in different groups across the hemispheres were studied using bivariate functional connectivity (FC) methods.
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Changes in the FC between EEG electrode pairs were investigated during the meditation practiced by long-term Brahmakumaris Rajyoga meditators with open eyes and during listening to music by controls as the comparable task.
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Common and distinct patterns were observed in distinct frequency bands in meditators and control groups. Node-degree strength was consistently higher in meditators than controls in theta band.
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Synergy and redundancy of the brain during different non-ordinary states of consciousness.
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This is a multicentric study on three different NSCs: Rajyoga meditation (RM), hypnosis, and self-induced cognitive trance (SICT).
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Synergistic and redundant information measures were used to compare and contrast the higher-order interactions during three NSCs.
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The synergy of the brain increased during RM and decreased during hypnosis and SICT, and redundancy decreased during RM.
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The pattern of changes observed in the synergy and redundancy values of each NSC is defined by the phenomenology of the NSC, including changes in the sense of self, environmental awareness, altered sensory perception, and selective attention.
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Respiration-entrained brain oscillations during slow-paced breathing.
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Coherence between the cortical activity (EEG) and respiration were analyzed during baseline and slow-paced breathing at six cpm guided by visual metronome.
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Significant coherence between respiration and EEG was observed, with no common localization across subjects. However, the coherence further increased during the slow-paced breathing at six cpm.
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Phase-amplitude coupling showed distinct patterns during baseline and slow-paced breathing in specific EEG frequency bands.
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The modulation index increased during slow-paced breathing compared to baseline, supporting the link between respiration and brain activity and providing possible insight into the benefits of therapeutic breathing exercises like pranayama.
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