Motor cortical activity preceding a memorized movement trajectory with an orthogonal bend

Two monkeys were trained to make an arm movement with an orthogonal bend, first up and then to the left ([symbol: see text]), following a waiting period. They held a two-dimensional manipulandum over a spot of light at the center of a planar working surface. When this light went off, the animals wer...

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Bibliographic Details
Published in:Experimental brain research 1993-07, Vol.95 (1), p.118-130
Main Authors: ASHE, J, TAIRA, M, SMYRNIS, N, PELLIZZER, G, GEORGAKOPOULOS, T, LURITO, J. T, GEORGOPOULOS, A. P
Format: Article
Language:English
Subjects:
Animals
Arm
Biological and medical sciences
Brain Mapping
Female
Fundamental and applied biological sciences. Psychology
Macaca mulatta
Male
Memory - physiology
Mental Processes - physiology
Motor Activity - physiology
Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration
Motor Cortex - physiology
Movement - physiology
Neurons - physiology
Space life sciences
Time Factors
Vertebrates: nervous system and sense organs
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Summary:Two monkeys were trained to make an arm movement with an orthogonal bend, first up and then to the left ([symbol: see text]), following a waiting period. They held a two-dimensional manipulandum over a spot of light at the center of a planar working surface. When this light went off, the animals were required to hold the manipulandum there for 600-700 ms and then move the handle up and to the left to receive a liquid reward. There were no external signals concerning the "go" time or the trajectory of the movement. It was hypothesized that during that period signs of directional processing relating to the upcoming movement would be identified in the motor cortex. Following 20 trials of the memorized movement trajectory, 40 trials of visually triggered movements in radially arranged directions were performed. The activity of 137 single cells in the motor cortex was recorded extracellularly during performance of the task. It was found that 62.8% of the cells changed activity during the memorized waiting period. During the waiting period, the population vector (Georgopoulos et al. 1983, 1984) began to grow approximately 130 ms after the center light was turned off; it pointed first in the direction of the second part of the memorized movement (
ISSN:0014-4819
1432-1106
DOI:10.1007/BF00229661