The Role of the Striatum in the Mental Chronometry of Action: A Theoretical Review

Three converging fields are critically reviewed in the context of the functions of the striatum; its anatomical relationships; reaction time and motor programming studies of Parkinson’s dis-ease; and neuropsychological studies of the role of the striatum in similar functions in experimental animals. Special consideration is given to the possible existence of parallel, segregated cortico-striatal loops, the role of the mesencephalic dopamine innervation of the neo-striatum, the utility of reaction time tasks for the separation of distinct “routes for action” and the development of analogous tests in animals with discrete and specific lesions of the striatum. Several elementary processes are identified that contribute to the early stages of response selec-tion. These can be denoted as spatial, temporal and cognitive aspects of response set. The implications for striatal function and dysfunction, specifically in Parkinson’s disease, are consid-ered.