Neural dynamics of reaching following incorrect or absent motor preparation.
Moving is thought to take separate preparation and execution steps. During preparation, neural activity in primary motor and dorsal premotor cortices achieves a state specific to an upcoming action but movements are not performed until the execution phase. We investigated whether this preparatory state (more precisely, prepare-and-hold state) is required for movement execution using two complementary experiments. We compared monkeys' neural activity during delayed and nondelayed reaches and in a delayed reaching task in which the target switched locations on a small percentage of trials. Neural population activity bypassed the prepare-and-hold state both in the absence of a delay and if the wrong reach was prepared. However, the initial neural response to the target was similar across behavioral conditions. This suggests that the prepare-and-hold state can be bypassed if needed, but there is a short-latency preparatory step that is performed prior to movement even without a delay.
Neurosciences Program, School of Medicine, Stanford University, Stanford, CA 94305, USA.
K Cora
KC
Ames
Department of Neurosurgery, Palo Alto Medical Foundation, Palo Alto, CA 94301, USA; Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
Stephen I
SI
Ryu
Neurosciences Program, School of Medicine, Stanford University, Stanford, CA 94305, USA; Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Neurobiology, School of Medicine, Stanford University, Stanford, CA 94305, USA. Electronic address: shenoy@stanford.edu.
Krishna V
KV
Shenoy
D000200:Action Potentials / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology*; D003463:Cues; D008253:Macaca mulatta; D008297:Male; D008959:Models, Neurological; D009046:Motor Neurons / Q000502:physiology*; D009068:Movement; D017711:Nonlinear Dynamics; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time