Structural and functional correlates of hypnotic depth and suggestibility

Area of Science:

• Neuroscience
• Psychology

Background:

• Individual differences in hypnotic suggestibility and depth are well-documented.
• The neurobiological underpinnings of these variations remain incompletely understood.

Purpose of the Study:

• To investigate the association between neuroanatomical differences and functional connectivity with self-reported hypnotic depth and suggestibility.
• To differentiate the neural correlates of hypnotic depth from those of hypnotic suggestibility.

Main Methods:

• Structural and resting-state functional magnetic resonance imaging (fMRI) was performed on 29 participants with varying hypnotic suggestibility.
• Voxel-based morphometry analyzed grey matter (GM) and white matter (WM) volumes.
• Independent component analysis identified functional networks, which were regressed against hypnotic depth, relaxation, and suggestibility.

Main Results:

• Hypnotic depth correlated positively with GM volume in the frontal cortex and anterior cingulate cortex (ACC).
• Hypnotic suggestibility correlated positively with GM volume in the left temporal-occipital cortex.
• Deeper hypnosis was associated with reduced anterior default mode network (DMN) connectivity; no significant correlations were found with WM volume.

Conclusions:

• Greater GM volume in the medial frontal cortex and ACC, alongside reduced DMN connectivity during hypnosis, facilitates deeper hypnotic experiences.
• Neuroanatomical and functional connectivity patterns suggest that hypnotic depth and suggestibility are distinct constructs.