Brain activation and individual differences of emotional perception and imagery in healthy adults: A functional near-infrared spectroscopy (fNIRS) study.

The current study investigated the brain activation and individual differences in perception and imagery of sad pictures versus happy and neutral pictures. Sixty-eight healthy adults were instructed to view and visualize sad, happy, and neutral pictures during 64-channel functional near-infrared spectroscopy (fNIRS) recording. The results indicated that emotional perception evoked increased occipital activation, while emotional imagery involved increased activation in the bilateral prefrontal and parietal cortex. Sad pictures evoked decreased brain activation in the occipital and prefrontal cortex than happy and neutral pictures. For women, imagery activation was greater than perception activation in the right parietal cortex. Additionally, participants' self-rated imagery vividness was positively correlated with the occipital activation during happy imagery and trait rumination was negatively correlated with the occipital activation during perception. The findings suggest that emotional perception may involve the bottom-up sensory input, while emotional imagery may involve the top-down cognitive processes. Healthy individuals engage decreased cognitive resources for sad perception and imagery. Moreover, our observation could provide useful information to establish fNIRS assessment as an objective tool to monitor the emotional status on an individual trait basis.