Supplementary motor area activation while tapping bimanually different rhythms in musicians

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Neuroscience

Background:

• Cortical DC-potentials reflect neural activity.
• Bimanual motor sequences involve complex coordination.
• The supplementary motor area (SMA) is implicated in motor planning.

Purpose of the Study:

• Investigate brain activation patterns during bimanual rhythmic tapping.
• Differentiate neural activity between simple and complex bimanual tasks.
• Explore the role of the SMA in precise motor timing.

Main Methods:

• Recorded cortical DC-potentials from 15 musicians.
• Analyzed brain activity time-locked to movement onsets.
• Compared neural responses during synchronous (2:2) vs. asynchronous (2:3) rhythms.
• Mapped radial current densities across the scalp.

Main Results:

• Synchronous tapping activated primary motor cortices (MI).
• Complex rhythm tapping additionally activated the mesial, central cortex (SMA).
• SMA activation preceded difficult rhythm execution by approximately 4 seconds.
• Preparatory set differs between simple and complex bimanual tasks.

Conclusions:

• The SMA plays a crucial role in controlling movement initiation for complex, precisely timed bimanual sequences.
• Pre-performance SMA activation highlights its function in motor preparation and timing.
• Distinct neural activation patterns differentiate simple and complex bimanual motor control.