Emotion-related cerebral blood flow changes in the ventral medial prefrontal cortex: An NIRS study.

The current study examined whether cerebral blood flow (CBF) changes in the anterior ventral medial prefrontal cortex (VMPFC) represent responses to emotional stimuli instead of cognitive control of emotion during distraction tasks, as suggested by our previous near-infrared spectroscopy (NIRS) study. The functional distinction of MPFC regions is occasionally difficult due to their multiple functions. Here, we addressed some remaining concerns from our previous distraction studies, and employed the distraction paradigm, in which negative or neutral images are presented as emotional stimuli; a rest period is included in one condition and working memory (distraction) tasks in the other. To extract the components of CBF changes associated with responses to negative emotional stimuli (defined as emotion-related CBF changes), we subtracted the CBF changes obtained in the neutral condition from those in the negative condition. We found that emotion-related CBF changes in the anterior left VMPFC were significantly greater in the rest condition than in the distraction task condition. These findings imply that the distraction task decreased unnecessary brain activities, resulting in decrease in the emotion-related CBF changes. They support our previous findings, indicating that CBF changes in anterior VMPFC regions, measured using NIRS, are specifically associated with responses to emotional stimuli.