Event-related brain potential and heart rate manifestations of visual selective attention

Twenty-eight volunteers were instructed to attend stimuli presented at one side of the computer screen and to ignore stimuli presented at the other si de. Both attended and unattended stimulus series consisted of targets (25%) and nontargets (75%) defined on the basis of stimulus shape. Attended targ ets required a binary choice based on stimulus color. Selective attention l ed to the expected increase in both midlatency (N2b) and late (P3) brain po tential components. Furthermore, selective attention led to increased antic ipatory cardiac slowing preceding the target stimulus and to increased prim ary bradycardia. Correlational analyses revealed a positive relation betwee n the effects of selective attention on N2b amplitude and primary bradycard ia suggestive of cortical involvement in the chronotropic control of heart rate.