title: Effects of ISI and stimulus probability on event-related go/nogo potentials after somatosensory stimulation.
abstract: The present study investigated the characteristics of the middle-latency negative potential of event-related potentials (ERPs) using somatosensory go/nogo tasks. We manipulated interstimulus interval (ISI) in Experiment 1 and stimulus probability in Experiment 2 and analyzed the subtracted difference waveform resulting from subtraction of the ERP evoked by the go stimulation from that evoked by the nogo stimulation. In Experiment 1, the peak latency of negativity became significantly longer as the ISI increased, but the peak amplitude was unchanged. The reaction time (RT) was longer with increasing ISI. In Experiment 2, manipulation of the stimulus probability yielded an increase in peak amplitude with decreasing probability of the nogo stimulus, but did not affect the latency. The RT increased as the probability of a nogo stimulus rose. Because manipulation of the ISI and stimulus probability elicited different brain activities, we hypothesized that manipulation of the ISI elicited a delay of the stimulus evaluation process including response inhibition, and that stimulus probability significantly affected the strength of the response inhibition process.
authors.affiliation: Department of Integrative Physiology, National Institute for Physiological Sciences, Myodaiji, 444-8585, Okazaki, Japan. nakata@nips.ac.jp
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nakata
authors.forename: Koji
authors.initials: K
authors.lastname: Inui
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Wasaka
authors.forename: Yohei
authors.initials: Y
authors.lastname: Tamura
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kida
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Kakigi
mesh_terms: D000328:Adult; D003071:Cognition / Q000502:physiology; D003657:Decision Making / Q000502:physiology*; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009433:Neural Inhibition / Q000502:physiology*; D011336:Probability; D011930:Reaction Time / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*; D014110:Touch / Q000502:physiology*