Hybrid dedicated and distributed coding in PMd/M1 provides separation and interaction of bilateral arm signals

• Main Authors: Carmena, J.M (Author), Dixon, T.C (Author), Ivry, R.B (Author), Merrick, C.M (Author), Wallis, J.D (Author)
• Format: Article
• Language: English
• Published: Public Library of Science 2021
• Subjects: animal; animal experiment; Animals; arm; Arm; article; Haplorhini; Macaca mulatta; motor cortex; Motor Cortex; nonhuman; physiology; psychomotor performance; Psychomotor Performance; rhesus monkey
• Online Access: View Fulltext in Publisher

 Pronounced activity is observed in both hemispheres of the motor cortex during preparation and execution of unimanual movements. The organizational principles of bi-hemispheric signals and the functions they serve throughout motor planning remain unclear. Using an instructed-delay reaching task in monkeys, we identified two components in population responses spanning PMd and M1. A "dedicated"component, which segregated activity at the level of individual units, emerged in PMd during preparation. It was most prominent following movement when M1 became strongly engaged, and principally involved the contralateral hemisphere. In contrast to recent reports, these dedicated signals solely accounted for divergence of arm-specific neural subspaces. The other "distributed"component mixed signals for each arm within units, and the subspace containing it did not discriminate between arms at any stage. The statistics of the population response suggest two functional aspects of the cortical network: One that spans both hemispheres for supporting preparatory and ongoing processes, and another that is predominantly housed in the contralateral hemisphere and specifies unilateral output. © 2021 Dixon et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.