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Lookup NU author(s): Dr Demetris Soteropoulos,
Professor Stuart BakerORCiD
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We investigated the different contribution of the corpus callosum (CC) and cerebellum to motor control in two macaque monkeys trained to perform a precision grip task with one or both hands. Recordings were made from antidromically identified CC cells and nearby unidentified neurons (UIDs) in the hand representation of the supplementary motor area (SMA) and compared with cells from the deep cerebellar nuclei (DCN). All cells showed their greatest modulation in activity (rate change locked to particular task event) during the movement epochs of the task (CC, 21.3 ± 22.2; UIDs, 36.2 ± 30.1 spike/s for contralateral trials; DCN, 63 ± 56.4 for ipsilateral trials; mean ± SD). Surprisingly, CC cells fired at very low basal rates compared with UIDs (3.9 ± 4.9 vs. 10 ± 9.1 spike/s) or DCN neurons (50.8 ± 23.8 spike/s). However, SMA cells had the greatest rate modulation to baseline ratio (CC: 12.1 ± 13.7; UID: 5.3 ± 5.4; DCN: 1.7 ± 2.0). This would allow them to code the timing of a behavioral event with better fidelity than DCN cells. A multivariate regression analysis between cell firing and EMG measured cells' representation of moment-by-moment modulations in muscle activity. CC neurons coded these real-time behavioral parameters significantly less well than the other cells types, using both linear and nonlinear models. Basal firing rate substantially constrains cell function. CC cells with low basal rates have restricted dynamic range for coding continuous parameters, but efficiently code the time of discrete behavioral events. DCN neurons with higher basal rates are better suited to control continuously variable parameters of movement. Copyright © 2007 The American Physiological Society.
Author(s): Soteropoulos DS, Baker SN
Publication type: Article
Publication status: Published
Journal: Journal of Neurophysiology
Print publication date: 01/11/2007
ISSN (print): 0022-3077
ISSN (electronic): 1522-1598
Publisher: American Physiological Society
PubMed id: 17715202
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