title: The pre-movement component of motor cortical local field potentials reflects the level of expectancy.
abstract: Cortical local field potentials (LFPs) are modulated in parallel with single neuron discharge, but the information they carry is often unclear. Multi-electrode recordings of both LFPs and single neuron activities were made in motor cortex as monkeys performed a delayed pointing task in which the probability of the moment of signal occurrence, and thus movement execution, was manipulated. A large positive LFP component (P1) appeared immediately preceding movement onset only under conditions of low probability, that is, when a response signal was weakly expected. The amplitude of P1 was much smaller when probability of signal occurrence was high, or when the same movement was self-paced. Although P1 has been described as being linked to the descending motor signal, we found that it was more closely associated with the processing of movement-related information than with the ultimate motor command. Its timing did not bear a fixed relationship with movement onset and its frequency of occurrence in each monkey varied in parallel with each animal's overall performance and the percentage of context-related "pre-processing" neurons encountered.
authors.affiliation: Mediterranean Institute of Cognitive Neuroscience (INCM), National Center for Scientific Research (CNRS) & Aix-Marseille University, 31 chemin Joseph Aiguier, 13402 Marseille Cédex 20, France. roux@incm.cnrs-mrs.fr
authors.forename: Sébastien
authors.initials: S
authors.lastname: Roux
authors.forename: William A
authors.initials: WA
authors.lastname: Mackay
authors.forename: Alexa
authors.initials: A
authors.lastname: Riehle
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001245:Association Learning / Q000502:physiology*; D001522:Behavior, Animal; D001931:Brain Mapping; D002755:Choice Behavior / Q000502:physiology; D004558:Electric Stimulation; D004576:Electromyography / Q000379:methods; D005071:Evoked Potentials / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D008253:Macaca mulatta; D008297:Male; D009044:Motor Cortex / Q000166:cytology / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D009474:Neurons / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013997:Time Factors