Neural dynamics of reaching following incorrect or absent motor preparation

• Published in: Neuron (Cambridge, Mass.) Vol. 81; no. 2; pp. 438 - 451
• Main Authors: Ames, K Cora, Ryu, Stephen I, Shenoy, Krishna V
• Format: Journal Article
• Language: English
• Published: United States Elsevier Limited 22.01.2014
• Subjects: Action Potentials - physiology; Analysis of Variance; Animals; Behavior; Cerebral Cortex - cytology; Cues; Macaca mulatta; Male; Models, Neurological; Motor Neurons - physiology; Movement; Nonlinear Dynamics; Patch-Clamp Techniques; Photic Stimulation; Psychomotor Performance - physiology; Reaction Time; Studies
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/j.neuron.2013.11.003

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.