Long-term modifications in motor cortical dynamics induced by intensive practice.

Area of Science:

• Neuroscience
• Motor Control
• Computational Neuroscience

Background:

• Goal-directed movements integrate sensory, temporal, and contextual information.
• Neuronal networks underpin sensorimotor functions, but their spatio-temporal organization for optimized behavior remains unclear.
• Temporal coordination of neural activity, like spike synchrony, may complement firing rate codes for efficient computation.

Purpose of the Study:

• To investigate if intensive practice induces long-term modifications in the temporal structure of neural synchrony and firing rate.
• To understand how practice affects the population-level activity in motor cortex during a timed movement task.

Main Methods:

• Three monkeys were trained on a delayed pointing task requiring accurate time estimation.
• Analyzed synchronous firing between simultaneously recorded motor cortex neurons using the "unitary event" technique.
• Quantified population-level synchrony evolution and temporal precision, comparing it with population firing rates.

Main Results:

• Task timing was encoded in the temporal structure of population spike synchronization.
• Practice strengthened and temporally localized synchrony, correlating with improved behavioral performance.
• Average population firing rate decreased as practice progressed.

Conclusions:

• Performance optimization via practice may involve enhancing the computational role of spike synchrony.
• This enhancement allows for efficient computation with reduced overall population activity.
• Neural synchrony's temporal structure is a key factor in motor learning and performance refinement.