subpallium

The subpallium is a subregion of the forebrain in vertebrates, located in the ventral portion of the telencephalon just beneath the pallium. In mammals it corresponds to the basal ganglia, a set of interconnected nuclei that regulate movement and other aspects of behavior. The term contrasts with the pallium, which is mainly related to the cerebral cortex and higher cognitive functions.

Anatomically, the subpallium includes the striatum (caudate nucleus and putamen), the pallidum (globus pallidus) and ventral structures such as the nucleus accumbens and the olfactory tubercle. Developmentally, the lateral ganglionic eminence gives rise to the striatum and parts of the olfactory tubercle, while the medial ganglionic eminence gives rise to the pallidal components and to various interneurons that migrate to the cortex and hippocampus.

The subpallial neurons are predominantly GABAergic. Through basal ganglia circuits, the subpallium influences thalamocortical activity via direct and indirect pathways, contributing to motor control and procedural learning. The ventral striatum and ventral pallidum are especially involved in reward, motivation, and goal-directed behavior.

Clinical relevance: Alterations in subpallial circuits are linked to movement disorders such as Parkinson's disease and Huntington's disease, as well as neuropsychiatric conditions including obsessive-compulsive disorder and addiction.

Across vertebrates, the subpallium is an evolutionarily conserved structure with homologous regions across species, reflecting its fundamental role in coordinating movement, motivation, and reinforcement.