Reduction in motor error by presenting subthreshold somatosensory information during visuomotor tracking tasks

Area of Science:

• Neuroscience
• Biomedical Engineering
• Human Motor Control

Background:

• Sensory noise can impact nervous system functions.
• Stochastic resonance is a phenomenon where noise enhances signal detection or system performance.
• This effect has potential applications for improving biological functions, including motor control.

Purpose of the Study:

• To investigate the effect of electrical stimulation-induced somatosensory noise on grip force adjustment ability.
• To determine if stochastic resonance can enhance motor control during a visuomotor tracking task.
• To explore individual differences in response to sensory noise for motor control enhancement.

Main Methods:

• A visuomotor tracking task was used to assess grip force adjustment.
• Participants performed force generation (FG), force relaxation (FR), and constant contraction phases.
• Subthreshold electrical stimulation was applied to induce somatosensory noise, and its intensity varied.
• Measures included coefficient of variation and absolute motor error in grip force.

Main Results:

• Subthreshold noise significantly reduced coefficient of variation in the Constant phase and motor errors in FG and Constant phases compared to no noise.
• No significant differences were found among other noise intensity conditions.
• A significant negative correlation was observed between baseline motor error and the change in motor error after stimulation, indicating noise benefited those with larger errors.
• Individuals with smaller baseline motor errors showed less improvement.

Conclusions:

• Somatosensory noise, through stochastic resonance, can enhance grip force adjustment ability, particularly in individuals with larger motor errors.
• The effectiveness of subthreshold noise varies with individual differences in motor control.
• Stochastic resonance shows promise as a method for improving motor control ability.