Investigation of brain activity after interaction with seal robot measured by fNIRS

Brain activities during interaction with a seal robot, “PARO,” and subsequent resting periods were measured by functional near-infrared spectroscopy (fNIRS). In this study, there were two experimental tasks: interaction with PARO switched ON (PARO ON) and interaction with PARO switched OFF (PARO OFF) with a one-minute rest before and after the tasks. The results show significant decreased brain activities around the motor cortex area after the PARO OFF task compared with those during the PARO OFF task. These areas of the brain are supposed to be a function of planning, control, and execution of voluntary movement. This indicates that when participants touch and interact with PARO, they might voluntarily interact. Therefore, there was a reduction of brain activity in the brain areas related to the function of voluntary movement, the so-called “motor cortex area.” Conversely, there were significant decreased brain activities in the left side of the frontal areas after the PARO ON task compared with those during the PARO ON task. The results suggest that when participants interact with PARO, they might recognize the positive emotional gesture expression of PARO. Therefore, after interaction with PARO, brain activities in the areas related to happy emotion processing were reduced. The results explain the improvement of mood by interaction with PARO from of a physiological point of view.