A cognitive signal for the proactive timing of action in macaque LIP.
Natural movements often occur without any immediate external event to cause them. In contrast to reactive movements, which are directly triggered by external cues, it is less clear how these proactive actions are initiated or when they will be made. We found that single neurons in the macaque's lateral intraparietal area (LIP) exhibit gradual firing rate elevations that reach a consistent value--which may correspond to a threshold--at the time of proactive, but not reactive, arm movements. This activity differs from sensory- and motor-related activity recorded in nearby cortical areas and could provide an internal trigger for action when abrupt external triggers in the visual input are unavailable.
Maimon
Gaby
G
Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, Massachusetts 02115, USA.
Assad
John A
JA
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal; D003071:Cognition / Q000502:physiology*; D016015:Logistic Models; D008253:Macaca mulatta; D008297:Male; D008959:Models, Neurological; D009068:Movement / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010296:Parietal Lobe / Q000166:cytology / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology; D013997:Time Factors; D013998:Time Perception / Q000502:physiology*