Figure 4.

Model scheme. (A) Afferents carrying sensory information from each stimulus (just one stimulus is depicted in this figure) impinge on a population of Go and NoGo cells, which compete with each other for determining behavior. (B) The probability of a Go action upon sampling of item X (P(Go|X)) is dependent on the relative synaptic weights from item X sensory stimuli to the cell populations. The probability of a NoGo action is given by P(NoGo|X) = 1 − P(Go|X), and similar formulas hold for P(Go|Y) and P(NoGo|Y). (C) Shown are possible outcomes following Go (top) and NoGo (bottom) responses to an item. A strengthening of connections between the stimulus and the cell population determining behavior occurs if the behavior led to reward; otherwise, a weakening of these connections occurs.