Facial expressions express internal information such as emotions and physical condition, therefore recognizing the facial expressions of others is important for understanding them and establishing smooth social communication. It is assumed that there is a change in brain activity in recognizing facial expressions when the lower part of the face is shielded by a face mask compared to when the face is unshielded. Neuroimaging studies have revealed that several areas including prefrontal cortex participate in the processing of facial expressions. In this study, functional near-infrared spectroscopy (fNIRS) was used to examine brain activity in the prefrontal cortex when recognizing facial expressions of masked and unshielded faces, and whether there are differences in brain activity depending on the emotion expressed by the other person.
