Figure 5.

Neural mechanism for generating memory-guided saccades (MGSs). Hikosaka et al. showed that the initiation of an MGS is mediated by cortical commands projected via the caudate nucleus and substantia nigra pars reticulata (SNr) to the superior colliculus (SC). This pathway corresponds to the direct pathway of the basal ganglia (BG). It contains two inhibitory neurons, i.e., from the caudate to the SNr, and then from the SNr to the SC, hence the name double inhibition pathway. A phasic inhibition of the high-frequency firing of the SNr by the caudate nucleus disinhibits the downstream SC, allowing a saccade to occur. Reproduced with permission from Hikosaka et al. (2000).⁵⁸⁾