Sensory Feedback Reduces Individuality by Increasing Variability within Subjects.

Area of Science:

• Neuroscience
• Motor Control
• Biomechanics

Background:

• Behavioral variability is common but not merely noise, as humans leverage it for motor tasks.
• The role of sensory feedback in controlling motor variability, both task-relevant and task-irrelevant, requires further investigation.
• Understanding variability across and within subjects is crucial for motor control research.

Purpose of the Study:

• To investigate how sensory feedback influences motor variability within and across subjects during swallowing.
• To determine if sensory feedback is the mechanism that reduces individuality in motor control.
• To relate motor program components, modulated by sensory feedback, to behavioral efficacy.

Main Methods:

• Analysis of motor pool durations and relative timings in swallowing motor patterns.
• Comparison of motor patterns with and without sensory feedback at the level of identified motor neurons.
• Correlation of motor program components with behavioral efficacy.

Main Results:

• Sensory feedback significantly reduces variability across subjects for motor program components crucial to swallowing efficacy.
• Surprisingly, sensory feedback increases variability within subjects for these same components.
• Individual differences in motor neuronal activity are controlled by sensory feedback, enabling access to a shared solution space.

Conclusions:

• Sensory feedback plays a dual role in motor variability, reducing inter-subject differences while increasing intra-subject variability.
• This mechanism allows for both individual adaptation and access to a common, effective motor control strategy.
• The findings provide insights into how sensory feedback shapes motor learning and execution.