Dopamine and Its Actions in the Basal Ganglia System

The dopaminergic system is implicated in a broad range of neurological syndromes, including Parkinson’s disease, dementia, dystonia, stuttering, depression, and schizophrenia. It is likely that systems-level computer simulations will guide future therapeutic interventions that seek to mitigate or counteract deficiencies or abnormalities in the dopaminergic system. In the absence of an arsenal of symptom-specific “magic bullet” pharmacotherapies that are fully effective, with no problematic side effects, it is likely that the best results will be obtained from therapies that combine drugs, drug cocktails, or focal surgical implants with specialized behavioral training regimes that promote function normalization via endogenous synaptic plasticity and learning. Developing such hybrid therapies will be aided by the kind of understanding that emerges from realistic simulations of the ramifying effects of system parameters and experiential regimes. After presenting a self-contained summary of dopamine actions at key sites within basal ganglia circuits, this chapter homes in on several themes that have emerged from recent studies, and that are likely to be critical for improved simulations of fundamental basal ganglia contributions to learning and performance, in health and disease.