A neural correlate for common trait dissociation: Decreased EEG connectivity is related to dissociative absorption.

Dissociative absorption—a tendency to become deeply immersed in an experience while losing awareness of one's surroundings—is linked to reduced electrical connectivity in the brain. In 84 healthy Israeli soldiers, resting-state EEG showed that those with higher dissociative absorption had decreased coherence (a measure of connectivity) between frontal and occipital regions, and between central and parietal regions. These effects were strongest in the left hemisphere and in slow-wave brain rhythms (theta and delta). The findings suggest that dissociative absorption reflects less integrated cortical activity, offering insight into the neural basis of consciousness and personality.

Study at a glance

Abstract

Dissociation refers to a disintegration between psychological elements; common manifestations are embodied in "absorption and imaginative involvement," a propensity for being immersed in a stimulus while oblivious to the environment, and acting without awareness. Trait dissociation was hypothesized to relate to lower EEG signal connectivity, but studies on healthy populations are scarce. The present study set out to examine whether dissociative absorption in a nonclinical sample would be associated with decreased intrahemispheric coherence. In 84 healthy Israeli soldiers (49% females; Mage = 22.24, SD = 2.64), resting-state electroencephalography (rsEEG) was recorded for a period of 3 min with eyes closed and 3 min with eyes open. Decreased coherence was related to high dissociative absorption in the long (frontal-occipital) range, and in one of the pairs of the short range (central-parietal). The effects emerged mostly in the left hemisphere, in both eyes-open and eyes-closed conditions, and for a range of spectral bands, although long-range effects were more pronounced in slow-wave bands (theta and delta). Dissociative absorption is manifested in segregated cortical activity, supporting the notion that it may represent less integrated mental functioning. The findings contribute to our understanding of the neural correlates of consciousness and personality.