title: Encoding of movement fragments in the motor cortex.
abstract: Previous studies have suggested that complex movements can be elicited by electrical stimulation of the motor cortex. Most recording studies in the motor cortex, however, have investigated the encoding of time-independent features of movement such as direction, velocity, position, or force. Here, we show that single motor cortical neurons encode temporally evolving movement trajectories and not simply instantaneous movement parameters. We explicitly characterize the preferred trajectories of individual neurons using a simple exponential encoding model and demonstrate that temporally extended trajectories not only capture the tuning of motor cortical neurons more accurately, but can be used to decode the instantaneous movement direction with less error. These findings suggest that single motor cortical neurons encode whole movement fragments, which are temporally extensive and can be quite complex.
authors.affiliation: Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois 60637, USA. nicho@uchicago.edu
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Hatsopoulos
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Xu
authors.forename: Yali
authors.initials: Y
authors.lastname: Amit
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D003216:Conditioning, Operant; D008253:Macaca mulatta; D008959:Models, Neurological; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009949:Orientation / Q000502:physiology; D011434:Proprioception / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012815:Signal Processing, Computer-Assisted; D013028:Space Perception / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology; D013997:Time Factors