title: Neurons in Primary Motor Cortex Encode Hand Orientation in a Reach-to-Grasp Task.
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.
authors.affiliation: Institute of Life Science and School of Life Science, Nanchang University, Nanchang, 330031, China. chaolinma@ncu.edu.cn.|School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, 85287, USA. chaolinma@ncu.edu.cn.
authors.forename: Chaolin
authors.initials: C
authors.lastname: Ma
authors.affiliation: School of Automation, Huazhong University of Science and Technology, Wuhan, 430074, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Ma
authors.affiliation: School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, 85287, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Fan
authors.affiliation: School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, 85287, USA. jiping.he@asu.edu.|School of Automation, Huazhong University of Science and Technology, Wuhan, 430074, China. jiping.he@asu.edu.|Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing, 100081, China. jiping.he@asu.edu.|Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, 430074, China. jiping.he@asu.edu.
authors.forename: Jiping
authors.initials: J
authors.lastname: He
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001696:Biomechanical Phenomena; D006225:Hand / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D008253:Macaca mulatta; D008297:Male; D009044:Motor Cortex / Q000166:cytology* / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D009949:Orientation / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*
keywords: Hand orientation; Non-human primate; Primary motor cortex; Single neuron recording