1Institute of Life Science and School of Life Science, Nanchang University, Nanchang 330031, China
2School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ 85287, USA
3School of Automation, Huazhong University of Science and Technology, Wuhan 430074, China
4Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing 100081, China
5Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China

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.

Keywords

Primary motor cortex,Single neuron recording,Hand orientation,Non-human primate

[SpringerLink]