The levels and persistence of Arc induction appear to differ depending on the brain region and cell type. For example, different regions of the hippocampus (e.g. CA3 and CA1 [54,55]), and even varying cell types within a brain region (e.g. striatopallidal vs. striatonigral neurons within the striatum [5]), showed different Arc induction in response to behavioral tasks. These differences might provide information about the levels of activity in these cells/regions and how and when they function in learning and memory.