Objective. - Threatening stimuli encountered in peripersonal space (PPS) are processed differently from those encountered in extrapersonal space (EPS). This phenomenon is attributed to tonic top-down modulation. We hypothesized that prepulse inhibition (PPI) of a reflex, which has a protective function, may change according to whether the conditioning stimulus appears in PPS or EPS. We aimed to compare the strength of the PPI according to whether stimulation was delivered in PPS or EPS.