Figure 3.

Schematic representation of the connections from the nigra to the superior colliclus as recently identified by Kaneda et al., 2008. Blue circles and lines indicate inhibitory GABAergic neurons and connections. Green circles and lines indicate excitatory glutaminergic neurons and connections. Downward arrows indicate that these neurons project out of the colliculus and travel in the predorsal bundle neurons en route to the brainstem saccade generating machinery. It is unknown whether the connections from the nigra to the colliculus targeting the different neuron types in the colliculus arise from different neurons in the nigra. They were drawn separately for clarity. SGS = superficial layer of the colliculus, stratum griseum superficiale; SGI = intermediate layers of the colliculus, stratum griseum intermediale.