Cognitive and social functions of the mammalian striatum

The striatum is formed by a group of subcortical nuclei in the brain with analogues shared by all vertebrates, and as such, it has frequently been described in the literature as being evolutionarily "conserved." However, its extensive connections with the neocortex, and its involvement in a variety of complex cognitive and behavioral processes, particularly those associated with social cognition, indicate phylogenetic modification that bears further exploration in an evolutionary context. Here, I will explore the anatomy and cognitive functions of the striatum, highlighting its role as an integral part of the social brain. I will assert that major modifications in its connectivity with the dynamically evolving neocortex yield important functional differences across species, contributing to derived cognitive specializations in the primate lineage. Finally, I will raise questions regarding the chemical anatomy of the striatum across species, calling for further investigation of interspecific differences in chemical anatomy. These differences in connectivity and chemical anatomy likely underlie features of primate and human cognition representing uniquely evolved specialization