Conservation of preparatory neural events in monkey motor cortex regardless of how movement is initiated

• Published in: eLife Vol. 7
• Main Authors: Lara, Antonio H, Elsayed, Gamaleldin F, Zimnik, Andrew J, Cunningham, John P, Churchland, Mark M
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 22.08.2018; eLife Sciences Publications, Ltd; eLife Sciences Publications Ltd
• Subjects: Action Potentials - physiology; Animals; Biomechanical Phenomena; Brain; Electromyography; Haplorhini - physiology; Male; motor cortex; Motor Cortex - physiology; Movement - physiology; movement preparation; Muscles - physiology; Neural Pathways - physiology; Neuroscience; reaching; Reaction Time; Task Performance and Analysis; rhesus macaque; reaching; motor cortex; movement preparation; neuroscience
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.31826

A time-consuming preparatory stage is hypothesized to precede voluntary movement. A putative neural substrate of motor preparation occurs when a delay separates instruction and execution cues. When readiness is sustained during the delay, sustained neural activity is observed in motor and premotor areas. Yet whether delay-period activity reflects an essential preparatory stage is controversial. In particular, it has remained ambiguous whether delay-period-like activity appears before non-delayed movements. To overcome that ambiguity, we leveraged a recently developed analysis method that parses population responses into putatively preparatory and movement-related components. We examined cortical responses when reaches were initiated after an imposed delay, at a self-chosen time, or reactively with low latency and no delay. Putatively preparatory events were conserved across all contexts. Our findings support the hypothesis that an appropriate preparatory state is consistently achieved before movement onset. However, our results reveal that this process can consume surprisingly little time.