CTX=cortex
THAL=thalamus
STR=striatum
GPe=globus pallidus (external)
GPi=globus pallidus (internal)
STh=subthalamic nucleus
SNr=substantia nigra pars reticulata
SNc=substantia nigra pars compacta

CONNECTIVITY WITHIN THE BASAL GANGLIA

This diagram shows some of the major connections within the basal ganglia. Connections shown in red have an excitatory effect on target structures (primarily through the transmitter glutamate). Connections shown in blue have an inhibitory effect (primarily through the transmitter GABA). Notice the substantia nigra is divided into two here, the pars reticulata and the pars compacta. The pars compacta contains dopamine producing neurons which have a large projection to the striatum (shown in magenta).