Brain Activity and Functional Connectivity Associated with Hypnosis

This study was a very detailed and well controlled study of brain activity associated with hypnosis. 57 subjects with either very high or very low levels of hypnotisability were subjected to various conscious conditions during functional magnetic resonance imaging. All subjects underwent four conditions in the scanner: rest, memory retrieval, and two different hypnosis experiences.  These studies confirmed and extended the results of previous studies using similar methodologies measuring brain physiology. Three brain regions were observed to consistently show altered activity in response to hypnosis as compared to controls experiencing memory and rest. Similar to previous studies, hypnotic state was characterised by decreased low frequency amplitude in the dorsal anterior cingulate cortex. The dACC plays a role in attention control determining what we should attend and what we should ignore. Its selective hypnotically induced deactivation is in alignment with the theory that hypnosis invoked a suspension of critical judgment and an ability to immerse oneself in the task and suspend judgement and reduce awareness of alternatives.

Their second finding was that of increased functional connectivity between the executive control and the insular portion of the salience network from rest states to hypnosis states in highly susceptible subjected compared to lows. Since the insula is involved in the processing of body control and experience, emotion, empathy and pain processing this fits well with previous clinical observations of hypnotherapy affecting these experiences and perceptions.

The third finding was an uncoupling of the connectivity between the executive control network and default mode network during hypnosis. They hypothesise the engagement of the hypnotic state is associated with detachment from internal mental processes such as mind wandering and self-reflection supporting the idea hypnosis is a different state of consciousness rather than a reduced level of arousal.

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