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Titolo:
NEURAL MODEL OF CEREBELLAR LEARNING FOR ARM MOVEMENT CONTROL - CORTICO-SPINO-CEREBELLAR DYNAMICS
Autore:
CONTRERASVIDAL JL; GROSSBERG S; BULLOCK D;
Indirizzi:
BOSTON UNIV,DEPT COGNIT & NEURAL SYST BOSTON MA 02215 BOSTON UNIV,DEPT COGNIT & NEURAL SYST BOSTON MA 02215 BOSTON UNIV,CTR ADAPT SYST BOSTON MA 02215
Titolo Testata:
Learning & memory
fascicolo: 6, volume: 3, anno: 1997,
pagine: 475 - 502
SICI:
1072-0502(1997)3:6<475:NMOCLF>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
PRIMATE MOTOR CORTEX; RED NUCLEUS; PURKINJE-CELL; RENSHAW CELLS; AREA 5; RUBROSPINAL TRACT; NEURONAL-ACTIVITY; AXON COLLATERALS; GLOBUS PALLIDUS; SIZE-PRINCIPLE;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
108
Recensione:
Indirizzi per estratti:
Citazione:
J.L. Contrerasvidal et al., "NEURAL MODEL OF CEREBELLAR LEARNING FOR ARM MOVEMENT CONTROL - CORTICO-SPINO-CEREBELLAR DYNAMICS", Learning & memory, 3(6), 1997, pp. 475-502

Abstract

A neural network model of opponent cerebellar learning for arm movement control is proposed The model illustrates how a central pattern generator in cortex and basal ganglia, a neuromuscular force controller in spinal cord, and an adaptive cerebellum cooperate to reduce motor variability during multijoint arm movements using mono- and hi-articularmuscles. Cerebellar learning modifies velocity commands to produce phasic antagonist bursts at interpositus nucleus cells whose feed-forward action overcomes inherent limitations of spinal feedback control of tracking. Excitation of or motoneuron pools, combined with inhibition of their Renshaw cells by the cerebellum, facilitate movement initiation and optimal execution. Transcerebellar pathways are opened by learning through long-term depression (LTD) of parallel fiber-Purkinje cellsynapses in response to conjunctive stimulation of parallel fibers and climbing fiber discharges that signal muscle stretch errors. The cerebellar circuitry also learns to control opponent muscles pairs, allowing cocontraction and reciprocal inhibition of muscles, Learning is stable, exhibits load compensation properties, and generalizes better across movement speeds if motoneuron pools obey the size principle. The intermittency of climbing fiber discharges maintains stable learning. Long-term potentiation (LTP) in response to uncorrelated parallel fiber signals enables previously weakened synapses to recover. Loss of climbing fibers, in the presence of LTP, can erode normal opponent signalprocessing. Simulated lesions of the cerebellar network reproduce symptoms of cerebellar disease, including sluggish movement onsets, poor execution of multijoint plans, and abnormally prolonged endpoint oscillations.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 03:24:03