title: Contributions of functional imaging to understanding parkinsonian symptoms.
abstract: Brain imaging experiments identify plausible circuits involved in the genesis of the cardinal symptoms of Parkinson's disease. Akinesia is linked to hypoactivation of the supplementary motor area secondary to insufficient thalamocortical facilitation. Overactivation in other areas such as the lateral premotor and parietal cortex probably represents a compensatory mechanism. Bradykinesia is associated with abnormal functioning within intrinsic basal ganglia circuitry for scaling movements to appropriate magnitude. Parkinson's disease tremor is localized to pontine- and mesencephalic-cerebellar-thalamic circuits, with abnormalities of both dopamine and serotonin neurotransmission. There is a need to understand the anatomic intersections where information is shared across these circuits.
authors.affiliation: Center for Cognitive Neuroscience, Dartmouth Brain Imaging Center, 6162 Moore Hall, Dartmouth College, Hanover, New Hampshire 03755 USA. scott.t.grafton@dartmouth.edu
authors.forename: Scott T
authors.initials: ST
authors.lastname: Grafton
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000503:physiopathology*; D006801:Humans; D018476:Hypokinesia / Q000209:etiology / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008959:Models, Neurological; D009434:Neural Pathways / Q000033:anatomy & histology / Q000503:physiopathology*; D018377:Neurotransmitter Agents / Q000378:metabolism; D010300:Parkinson Disease / Q000503:physiopathology*; D049268:Positron-Emission Tomography; D014202:Tremor / Q000209:etiology / Q000503:physiopathology
chemical_list: D018377:Neurotransmitter Agents