title: Abnormal sensory gating in basal ganglia disorders.
abstract: Basal ganglia encompass four to five distinct loops to allow parallel processing of information. Among them, the most intensively studied is the motor loop, which includes two distinct direct and indirect pathways. The direct pathway exerts facilitatory influence upon the motor cortex, whereas the indirect pathway exerts an inhibitory effect. Overall, this dual system provides a center(excitatory)-surround-(inhibitory) mechanism to focus its effect on selected cortical neurons, and several lines of evidence suggest that this center-surround mechanism is used to focus the output on a specific group of muscles required for performing a specific task. This operation is made possible through opening the sensory channel for the expected sensory feed-back afferents during movement. Thus, one of the important functions of basal ganglia seems to be the gating of sensory input for motor control. Dystonia may be caused by a mismatch between sensory input versus motor output, and parkinsonism may be viewed as a disorder of gain control of this sensorimotor integration.
authors.affiliation: Dept. of Neurology Institute of Health Bioscience, Tokushima University, Graduate School of Medicine, Tokushima, Japan. rkaji@clin.med.tokushima-u.ac.jp
authors.forename: Ryuji
authors.initials: R
authors.lastname: Kaji
authors.forename: Ryou
authors.initials: R
authors.lastname: Urushihara
authors.forename: Nagako
authors.initials: N
authors.lastname: Murase
authors.forename: Hideki
authors.initials: H
authors.lastname: Shimazu
authors.forename: Satoshi
authors.initials: S
authors.lastname: Goto
mesh_terms: D000818:Animals; D001480:Basal Ganglia Diseases / Q000503:physiopathology*; D006801:Humans; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal; D009475:Neurons, Afferent / Q000502:physiology*