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Updated: Jun 9, 2026
12:13
Assessing Primary Motor Cortex Excitability and Excitability Modulation by Pairing Transcranial Magnetic Stimulation with Electromyography
Published on: October 7, 2025
Periodicity and evoked responses in motor cortex
Jacob Reimer1, Nicholas G Hatsopoulos
1Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA.
Summary
Beta oscillations in the primary motor cortex (MI) influence how neural information about target location is encoded during movement. This suggests neural timing, not just elapsed time, is crucial for sensorimotor processing.
Area of Science:
- Neuroscience
- Motor Control
- Computational Neuroscience
Background:
- Primary motor cortex (MI) exhibits rhythmic beta-frequency (15-30 Hz) neural activity.
- The functional significance of this endogenous beta periodicity in motor control remains debated.
Purpose of the Study:
- To investigate the functional relevance of beta oscillations in MI during sensorimotor processing.
- To determine if beta oscillations modulate the encoding of target location information in MI neural activity.
Main Methods:
- Simultaneous multi-unit and local field potential recordings in the primary motor cortex of two macaque monkeys.
- Analysis of neural responses during continuous, self-paced movements to serially presented targets.
Main Results:
- Evoked spiking in MI occurred with precise timing relative to target appearance.
- The precise timing of evoked spiking was modulated by the phase of ongoing beta oscillations.
- Information encoding about target location depended on both elapsed time and oscillatory phase.
Conclusions:
- Beta oscillations in MI interact with evoked neural activity to shape information processing.
- Neural oscillatory phase, not just elapsed time, is a critical factor in early sensorimotor processing.
- Periodicity in neural firing may play a significant role in the cortical motor system's function.
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