Identifying brain areas for tactile perception through natural finger touch with MR-compatible tactile stimulus delivery system

Primates actively touch objects with their hands to collect information. In investigations of the tactile information processes, participants should experience tactile stimuli through active touch while brain activities are monitored. Here, we developed a pneumatic tactile stimulus delivery system (pTDS) that delivers various tactile stimuli on a programmed schedule and allows tactile perception through voluntary finger touches during MRI scanning. A pneumatic actuator moved tactile blocks and placed one in a finger hole. The time when an index finger touched a tactile stimulus was detected with a photosensor, allowing analysis of the touch-elicited brain responses. The brain responses were examined while the participants actively touched braille objects presented by the pTDS. BOLD responses during tactile perception were significantly stronger in a finger touch area of the contralateral somatosensory cortex compared with that of visual perception. This pTDS enables MR study of brain mechanisms for tactile processes through natural finger touch.