part_of part of part of has soma location has soma location striatum neuron indirect pathway medium spiny neuron matrix D2 medium spiny neuron A DRD2-expressing medium spiny neuron that is part of a matrix compartment of dorsal striatum. In Rhesus macaques, both matrix D1 and D2 medium spiny neuron cell types have been noted to have enriched gene expression of the following: EPHA4, GDA, STXBP6, and SEMA3E. Broadly understood, matrix MSNs receive neocortical inputs from the associative and sensorimotor cortex and give rise to the direct and indirect pathways. dorsal striatum matrix compartment