Abstract/Results:
| ABSTRACT:
It is widely disputed whether or not hypnosis, as distinct from responses to specific hypnotic suggestions, constitutes a discrete change in the operating state of the mind-brain system. If hypnotic responses require the on-set of such a background state, characteristic differences in the organization of neuronal activity should be visible between hypnotic and non-hypnotic conditions. This study sought to delineate a neuronal state ‘marker’ of hypnosis, thereby aiming to extend recent EEG findings of topographically specific increases in theta band functional connectivity and decreases in beta1 band connectivity in high compared to lows susceptible subjects following a hypnotic induction (Jamieson & Burgess, 2014). Specifically, this study extends the findings from sensor space (electrodes) to source space (cortical voxels). For this, resting EEG with eyes closed was recorded before, during and after hypnosis in 8 low susceptible and 11 high susceptible participants. Spectral band power analysis was conducted on the data, yielding, as expected, no significant results. Current source density estimations and connectivity analyses were done using the Key Institute eLORETA software. Cortical source activity did not show any significant hypnosis-related differences. However, as expected, hypnosis-related increases in functional connectivity in the theta band were found within nodes of the executive control network, in the salience network and in the default mode network. Moreover, also as expected, hypnosis-related decreases in beta1 band functional connectivity was found, specifically within nodes of the dorsal attention network and the executive control network. There were also two unexpected hypnosis-related increases in beta1 connectivity within nodes of the dorsal attention network and the salience network. These results indicate that reported changes in the theta and beta1 band functional connectivity in hypnosis are linked with a reorganization within the operations of the major networks regulating the flow of conscious experience, thereby supporting an altered state account of the hypnotic condition
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