et al., 2000). For example, it has been shown that genes involved in the regulation of glutamate receptor signaling pathways are especially enriched in their expression in the cerebellum, which contains a large number of glutamatergic granule cells— small cells with axons projecting glutamate (Roth, et al., 2006). Even between cortical layers there is a difference in gene expression due to distinct populations of projection neurons that are located in different cortical layers and areas of the neocortex (Molyneaux, Arlotta, Menezes, & Macklis, 2007).
