Initiate and control body movement, posture, muscle tone The basal ganglia consist mainly of deep-brain structures (the caudate nucleus, putamen, palladium, substantia nigra, and striatum) interconnected with cortical motor areas and the cerebellum. The basal ganglia work together with the cerebellum to select motor sequences for movements. The basal ganglia serve as the last station on the way before outgoing motor signals travel to muscles. The basal ganglia also keep the cortex up to date on how things are going through feedback pathways. Recently, the basal ganglia have been found to support language-related functions.
Basal Ganglia Pathologies
Parkinson’s disease: motor and cognitive disorder Parkinson’s was discovered in 1817 by James Parkinson (1755-1824). In Parkinson’s disease, dopamine-producing neurons in the substantia nigra (named for its dark color) die. As dopamine production dips markedly, tremors occur and the capacity to smoothly tense and relax muscles is lost as the basal ganglia then select conflicting motor programs. The basal ganglia can initially be made functional again by boosting production of dopaminergic neurons with the dopamine precursor L-dopa. But this treatment eventually becomes ineffective.
Huntington’s disease: motor and cognitive disorder Patients experience motor impairments as neurons in the striatum die. Jerky, uncontrollable movements are early symptoms. With progression of both Parkinson’s and Huntington’s disease, motor symptoms become increasingly debilitating and are accompanied by cognitive decline.
Basal Ganglia Summary
The basal ganglia support motor action, linguistic abilities, memory, and learning. Impairments of the basal ganglia often lead to compromised motor and cognitive abilities. Much pathology associated with the basal ganglia has to do with abnormal death of small groups of neurons.