FIGURE 4.

Influence of cholinergic agonist carbachol on persistent activity. (A) adapted from Egorov et al. (2002); (B) adapted from Major et al. (2018). (A) Example of persistent activity evoked in a rat entorhinal cortical neuron by a current pulse in the presence of carbachol. Neuronal discharge persists after cessation of stimulus, and after muscarinic blockade, and after muscarinic blockade. Neuronal discharge persists after cessation of stimulus in the presence of carbachol, but not during blockade of muscarinic receptors. (B) Illustration on the right shows experimental design of neuronal recording and carbachol iontophoresis. Shown on the left is the activity of two PFC neurons (top and bottom panels) with persistent rule-selective activity during the delay period is shown during control (left) and during carbachol (right) application. Carbachol attenuated WM activity for the antisaccade rule in the neuron shown in the top panel, while the activity of the neuron in the bottom panel was augmented by carbachol, but selectivity for the trial rule in the delay period was nevertheless diminished. Gray area shows the last 600 ms of the delay period prior to fixation offset. Reproduced with permission from Nature Publishing group.