Each dopamine neuron has an extremely large unmyelinated axonal arborization which can innervate up to 6% of the striatal volume in a rat.  Although all SNc dopamine cells project to both the striosome (or patch) and matrix neurochemical compartments of the striatum, most of the axonal territory of a dorsal tier neuron is in the matrix compartment while the majority of the axonal field of ventral tier neurons is in the striosomes. Nigrostriatal dopamine axons can also give rise to axon collaterals that project to other brain regions. For example, some, SNc nigrostriatal dopamine axons send axon collaterals to the pedunculopontine nucleus, the ventral palladium, subthalamic nucleus, globus pallidus, amygdala and the thalamus.