Fig. 6.

In the START model, conditioning, attention, and timing are integrated. Adaptively timed hippocampal signals R maintain motivated attention via a cortico-hippocampal-cortical feedback pathway, at the same time that they inhibit activation of orienting system circuits A via an amygdala drive representation D. The orienting system is also assumed to occur in the hippocampus. The adaptively timed signal is learned at a spectrum of cells whose activities respond at different rates r _j and are gated by different adaptive weights z _ij . A transient Now Print learning signal N drives learned changes in these adaptive weights. In the nSTART model, the hippocampal feedback circuit operates in parallel to the amygdala, rather than through it [Reprinted with permission from Grossberg and Merrill (1992)]