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Ma C, Ma X, Fan J, He J. Neurons in Primary Motor Cortex Encode Hand Orientation in a Reach-to-Grasp Task. Neurosci Bull 2017; 33:383-395. [PMID: 28389871 DOI: 10.1007/s12264-017-0126-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 02/20/2017] [Indexed: 11/30/2022] Open
Abstract
It is disputed whether those neurons in the primary motor cortex (M1) that encode hand orientation constitute an independent channel for orientation control in reach-to-grasp behaviors. Here, we trained two monkeys to reach forward and grasp objects positioned in the frontal plane at different orientation angles, and simultaneously recorded the activity of M1 neurons. Among the 2235 neurons recorded in M1, we found that 18.7% had a high correlation exclusively with hand orientation, 15.9% with movement direction, and 29.5% with both movement direction and hand orientation. The distributions of neurons encoding hand orientation and those encoding movement direction were not uniform but coexisted in the same region. The trajectory of hand rotation was reproduced by the firing patterns of the orientation-related neurons independent of the hand reaching direction. These results suggest that hand orientation is an independent component for the control of reaching and grasping activity.
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Affiliation(s)
- Chaolin Ma
- Institute of Life Science and School of Life Science, Nanchang University, Nanchang, 330031, China. .,School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, 85287, USA.
| | - Xuan Ma
- School of Automation, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jing Fan
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Jiping He
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, 85287, USA. .,School of Automation, Huazhong University of Science and Technology, Wuhan, 430074, China. .,Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing, 100081, China. .,Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, 430074, China.
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Sorrento GU, Henriques DYP. Reference frame conversions for repeated arm movements. J Neurophysiol 2008; 99:2968-84. [PMID: 18400956 DOI: 10.1152/jn.90225.2008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to further understand how the brain represents spatial information for shaping aiming movements to targets. Both behavioral and neurophysiological studies have shown that the brain represents spatial memory for reaching targets in an eye-fixed frame. To date, these studies have only shown how the brain stores and updates target locations for generating a single arm movement. But once a target's location has been computed relative to the hand to program a pointing movement, is that information reused for subsequent movements to the same location? Or is the remembered target location reconverted from eye to motor coordinates each time a pointing movement is made? To test between these two possibilities, we had subjects point twice to the remembered location of a previously foveated target after shifting their gaze to the opposite side of the target site before each pointing movement. When we compared the direction of pointing errors for the second movement to those of the first, we found that errors for each movement varied as a function of current gaze so that pointing endpoints fell on opposite sides of the remembered target site in the same trial. Our results suggest that when shaping multiple pointing movements to the same location the brain does not use information from the previous arm movement such as an arm-fixed representation of the target but instead mainly uses the updated eye-fixed representation of the target to recalculate its location into the appropriate motor frame.
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Affiliation(s)
- Gianluca U Sorrento
- York University, School of Kinesiology and Health Science, Bethune College, 4700 Keele St., Toronto, Ontario M3J 1P3, Canada
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