Hemispheric involvement during a bimanual RT task: P300 and motor potential.

Publisher Summary This chapter discusses hemispheric involvement during a bimanual reaction time (RT) task. Conflicting choice RT situations, in which the stimulus is coming from one side of the body, the response having to be given on the opposite side, have been studied until now using only behavioral indexes (RT), and to try to assess the amount of information processed during various stimulus-response compatible-incompatible situations. Electrophysiological correlates, however, can also be extremely helpful in such paradigms, as they may, with their latency, provide information on the timing of the mechanisms, with their amplitude, on the amount of information processing that takes place, and with their topography, on the localization of the neuronal population involved. If visual stimuli are delivered in random order either to the right, or to the left peripheral visual field, and if the subject is requested to respond only to one of these stimuli, the P300 component of the visual evoked potential (VEP) appears enhanced after the presentation of this stimulus.