This article tries to summarize the PBWM (Prefrontal cortex Basal ganglia Working Memory) model in the Executive chapter of the CCNBook. The PBWM model is further explained in O’Reilly & Frank’s paper: Making Working Memory Work: A Computational Model of Learning in the Prefrontal Cortex and Basal Ganglia, Neural Comput., 18(2) (2006). Here are points:

• The executive function requires controlling (i.e., keeping & releasing) states.
• The states are held in PFC.
• The control is carried out with the reinforcement learning mechanism described in the Motor chapter (cf. the nutshell).

Figure 1 is from Figure 5 in O’Reilly & Frank’s paper slightly modified explaining the model conformable to the last figure in the Motor nutshell.

Figure 1

Here, BG is controlling gates for states in PFC, while it was for controlling in general in the Motor chapter. Besides the gating, BG also controls output (Figure 10.11).

Figure 10.11 (from CCNBook)

For a most abstract level of understanding, these figures will suffice. The chapter notes that there is a hierarchy of control in the frontal cortex (Figure 10.16).

Figure 10.16 (from CCNBook)