Cyclic, Condition-Independent Activity in Primary Motor Cortex Predicts Corrective Movement Behavior.

Area of Science:

• Neuroscience
• Motor Control
• Computational Neuroscience

Background:

• Reaching movements exhibit significant condition-independent (CI) neural activity and cyclic dynamics.
• The role of these neural patterns in corrective movements remains less understood.

Purpose of the Study:

• To investigate if cyclic, CI neural activity in the primary motor cortex (M1) is present during corrective reaching movements.
• To determine if corrective movements are encoded as continuations of initial reaches or as discrete events.

Main Methods:

• Rhesus macaques performed a precision center-out task.
• Analysis of neural activity in M1 during initial and corrective reaching submovements.
• Comparison of neural trajectory phase and firing rate for predicting movement dynamics.

Main Results:

• Corrective movements displayed discrete, bell-shaped speed profiles similar to initial movements.
• CI cyclic neural trajectories were consistent and repeated for both initial and corrective submovements.
• The phase of CI neural activity more accurately predicted peak movement speed than firing rate regression.

Conclusions:

• Each corrective motor submovement is encoded by a distinct cycle of M1 neural activity.
• Corrective movements are not simple continuations but are independently encoded neural events.
• Cyclic CI neural dynamics in M1 play a crucial role in encoding discrete motor actions, including corrections.