Figure 4.

Striatum-LHb connections: possible circuits through GPb or VP. Our results suggest that the GPb-LHb connection is excitatory while the VP-LHb connection is inhibitory. A majority of GPb and LHb neurons encode negative reward prediction errors (e.g., excited by the unpredicted omission of reward), whereas a majority of VP neurons encode positive reward values (e.g., excited by the prediction of reward), The excitatory-inhibitory nature is unknown for the striatum-GPb and the striatum-VP connections; the sources of these connections might be the striosomes.