FIGURE 3.

Effects of local delivery of muscarinic antagonist scopolamine by microiontophoresis on PFC activity during pro- and antisaccade task. Adapted from Major et al. (2015). (A) Pro- and antisaccade task structure is shown. After central fixation, the fixation spot changes to a colored rule cue which flashes briefly. Subsequently the spot becomes white again. After a delay wherein the trial rule, based on the color of the rule cue, is maintained in WM, the fixation spot disappears, and after a brief gap, the peripheral stimulus appears left or right of the fixation spot. The subject makes a saccade toward (prosaccade) or away (antisaccade) from the spot, based on the current trial rule. Trial temporal structure are also shown. Illustration on the right shows the recording and iontophoresis technique. (B) Microiontophoresis of increasing doses of scopolamine cause increasing suppression of the activity of a PFC neuron that has delay-period activity preferring the pro-saccade rule. Right panel shows recovery after cessation of drug application.