On the anticipatory precue activity in motor cortex

Area of Science:

• Neuroscience
• Motor Control

Background:

• Motor cortical neurons activate during movement preparation, execution, and in response to visual cues.
• Some studies suggest motor cortex activation precedes expected cue presentation.

Purpose of the Study:

• Investigate anticipatory activity in motor cortical neurons preceding visual cues.
• Characterize the role of this precue activity in motor preparation and response.

Main Methods:

• Recorded activity of 1215 motor cortex neurons in macaque monkeys during a center-out reaching task.
• Task involved two consecutive delays (D1, D2) before cue presentation and movement execution.
• Classified neurons based on firing rate changes (increased D1up, decreased D1down) during the first delay (D1).

Main Results:

• 42% of recorded neurons exhibited anticipatory activity during D1.
• D1up neurons showed phasic activity post-cue and less activity during movement.
• D1down neurons displayed the opposite pattern, with sustained activity and involvement in preparation.

Conclusions:

• Precue activity in motor cortex may involve parallel processes: facilitating spatial information and downregulating corticospinal excitability.
• This anticipatory activity appears crucial for both early and late stages of motor preparation.
• Distinct neuronal firing patterns during anticipation correlate with subsequent response dynamics.