Functional brain basis of hypnotizability

Abstract

Context: Focused hypnotic concentration is a model for brain control over sensation and behavior. Pain and anxiety can be effectively alleviated by hypnotic suggestion, which modulates activity in brain regions associated with focused attention, but the specific neural network underlying this phenomenon is not known.

Objective: To investigate the brain basis of hypnotizability.

Design: Cross-sectional, in vivo neuroimaging study performed from November 2005 through July 2006.

Setting: Academic medical center at Stanford University School of Medicine.

Patients: Twelve adults with high and 12 adults with low hypnotizability.

Main outcome measures: Functional magnetic resonance imaging to measure functional connectivity networks at rest, including default-mode, salience, and executive-control networks; structural T1 magnetic resonance imaging to measure regional gray and white matter volumes; and diffusion tensor imaging to measure white matter microstructural integrity.

Results: High compared with low hypnotizable individuals had greater functional connectivity between the left dorsolateral prefrontal cortex, an executive-control region of the brain, and the salience network composed of the dorsal anterior cingulate cortex, anterior insula, amygdala, and ventral striatum, involved in detecting, integrating, and filtering relevant somatic, autonomic, and emotional information using independent component analysis. Seed-based analysis confirmed elevated functional coupling between the dorsal anterior cingulate cortex and the dorsolateral prefrontal cortex in high compared with low hypnotizable individuals. These functional differences were not due to any variation in brain structure in these regions, including regional gray and white matter volumes and white matter microstructure.

Conclusions: Our results provide novel evidence that altered functional connectivity in the dorsolateral prefrontal cortex and dorsal anterior cingulate cortex may underlie hypnotizability. Future studies focusing on how these functional networks change and interact during hypnosis are warranted.

Figures

Figure 1. Templates used to select decomposed spatial maps for each network per subject

Figure 2. Functional connectivity in the HIGH and LOW groups

(A) Difference in ICA maps of the salience network between the HIGH and LOW groups. Brain regions that show significantly greater connectivity in HIGH compared to LOW using t-tests (left) and large effect-size (right). (B) Significant clusters derived from one-sample t-tests of ICA maps for the salience, default-mode and executive-control networks for subjects with high and low hypnotizability (HIGH and LOW). Sagittal slices: x=-2 in Talairach coordinates. dACC: anterior cingulate cortex, DLPFC: dorsolateral prefrontal cortex. (C) Seed-based correlations showing significant difference in functional dACC-DLPFC connectivity between the HIGH and LOW groups.