Gating at cortical level contributes to auditory-motor synchronization during repetitive finger tapping

Area of Science:

• Neuroscience
• Sensorimotor Integration
• Auditory-Cued Movement

Background:

• Sensory integration is crucial for coordinating movements with external rhythms.
• The regulation and function of sensory input during increased tapping rates remain unclear.

Purpose of the Study:

• To investigate how sensory input is regulated during auditory-cued repetitive finger tapping at varying rates.
• To explore the functional consequences of altered sensory processing on sensorimotor integration and performance.

Main Methods:

• Recorded somatosensory evoked potentials (SEPs) from 13 healthy subjects during repetitive index finger tapping (0.5–4 Hz).
• Measured subcortical (P14) and cortical (N20/P25 in primary somatosensory cortex, S1) responses to ulnar nerve stimulation.
• Assessed the somatosensory temporal discrimination threshold (STDT) to evaluate temporal processing in S1.

Main Results:

• Sensory inputs were suppressed at subcortical and S1 levels during tapping.
• This suppression decreased in S1 but not subcortically at faster tapping rates (2–4 Hz vs. 0.5–1 Hz).
• Increased STDT at faster rates correlated negatively with performance, suggesting impaired temporal analysis in S1.

Conclusions:

• Faster tapping rates lead to reduced sensory suppression in S1, increasing sensory input.
• This heightened sensory input in S1 may cause temporal uncertainty, impairing sensorimotor integration and movement performance.
• Findings highlight the role of S1 sensory gating in maintaining precise motor control during demanding tasks.