Time Varying Encoding of Grasping Type and Force in the Primate Motor Cortex

Area of Science:

• Neuroscience
• Motor Control
• Primate Studies

Background:

• The primary motor cortex (M1) is crucial for movement planning and execution.
• The precise role of M1 in voluntary grasping remains incompletely understood.

Purpose of the Study:

• To investigate how M1 neurons encode grip type and force during a reach-to-grasp task.
• To elucidate the neural mechanisms underlying voluntary grasping in the motor cortex.

Main Methods:

• Analysis of M1 neuronal recordings in monkeys performing a delayed reach-to-grasp task.
• Utilizing single-cell and neural population analyses to decode grip and force parameters.
• Examining neural activity during preparation and execution phases of the task.

Main Results:

• Grip type (side vs. precision) was robustly and specifically encoded by a large M1 neuronal population.
• Force level was weakly and transiently encoded by mixed-selective neurons that also encoded grip type.
• Grip type information was stably decoded from M1 populations throughout task epochs.

Conclusions:

• Planning and executing specific grasping movements are high-level functions engaging M1 neurons.
• The execution of pulling force during grasping may be primarily encoded at lower levels of the motor system.
• M1 plays a critical role in the specific selection and planning of grip types.