Gamma band activity and its synchronization reflect the dysfunctional emotional processing in alexithymic persons

Abstract

In the present study, we investigated the gamma band response and its phase synchrony between electrodes in alexithymia, which is characterized by a disability in identifying and describing feelings. Individuals with high and low alexithymia scores were selected according to the scores on the 20-item Toronto Alexithymia Scale. EEG was recorded from alexithymic and nonalexithymic persons viewing emotionally negative or neutral stimuli. Nonalexithymic persons exhibited increased gamma band power and phase synchronization at the 400-450-ms time window when processing emotionally negative stimuli. Neither enhanced gamma band power nor phase synchronization was observed in alexithymic persons in the negative emotion condition. These results suggest that gamma band activity reflects emotional processing, and alexithymic persons may have a deficit in communication between brain regions or in the utilization of memory or emotional information during the processing of emotional stimuli.