title: On the anticipatory precue activity in motor cortex.
abstract: Motor cortical neurons are activated during movement preparation and execution, and in response to task-relevant visual cues. A few studies also report activation before the expected presentation of cues. Here, we study specifically this anticipatory activity preceding visual cues in motor cortical areas. We recorded the activity of 1215 neurons in the motor cortex of two macaque monkeys while they performed a center-out reaching task, including two consecutive delays of equal duration, known in advance. During the first delay (D1), they had to await the spatial cue and only reach to the cued target after the second delay (D2). Forty-two percent of the neurons displayed anticipatory activity during D1. Among these anticipatory neurons, 59% increased (D1up) their activity and the remaining decreased (D1down) their activity. By classifying the neurons according to these firing rate profiles during D1, we found that the activity during D2 differed in a systematic way. The D1up neurons were more likely to discharge phasically soon after the spatial cue and were less active during movement execution, whereas the D1down neurons showed the opposite pattern. But, regardless of their temporal activity profiles, the two categories seemed equally involved in early and late motor preparation, as reflected in their directional selectivity. This precue activity in motor cortex may reflect two complementary, coexisting processes: the facilitation of incoming spatial information in parallel with the downregulation of corticospinal excitability to prevent a premature response.
authors.affiliation: Institut de Neurosciences de la Timone, CNRS-Université Aix-Marseille, UMR 7289, 13385 Marseille Cedex 5, France. joachim.confais@univ-amu.fr
authors.forename: Joachim
authors.initials: J
authors.lastname: Confais
authors.forename: Bjørg Elisabeth
authors.initials: BE
authors.lastname: Kilavik
authors.forename: Adrián
authors.initials: A
authors.lastname: Ponce-Alvarez
authors.forename: Alexa
authors.initials: A
authors.lastname: Riehle
mesh_terms: D000818:Animals; D059031:Anticipation, Psychological / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology; D003463:Cues; D016208:Databases, Factual; D004558:Electric Stimulation; D055724:Electrophysiological Phenomena; D008253:Macaca mulatta; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009044:Motor Cortex / Q000502:physiology; D009068:Movement / Q000502:physiology; D010775:Photic Stimulation; D011153:Population; D011597:Psychomotor Performance / Q000502:physiology; D014785:Vision, Ocular / Q000502:physiology