Figure 4.

Implementation of the BABE model. Separated pools of neurons represent gray matter nuclei and cortical regions; the height and color of the each unit represents the amount of neuronal activation. Dotted arrows represent inhibitory projections, while solid lines represent excitatory projections. Context, cortical region representing the current decision context (i.e., one of the pairs AB, CD, or EF); Time, cortical region representing the current phase in the decision trial; LV_e, LV_i, PV_e, PV_i, components of the PVLV reinforcement learning system (see main text for details); Da, dopaminergic neurons; SP, striatopallidal projection neurons; SN, striatonigral projection neurons; TAN, striatal tonically active neurons (i.e., cholinergic interneurons).