Motor inhibition and response expectancy: a Laplacian ERP study

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Psychology

Background:

• During choice reaction time tasks, the contralateral motor cortex activates for the required response.
• The ipsilateral motor cortex, not directly involved, typically shows inhibition.
• The function of this ipsilateral inhibition remains debated, with theories suggesting error prevention.

Purpose of the Study:

• To investigate if ipsilateral motor cortex inhibition is an active mechanism to prevent errors.
• To test the hypothesis that error risk modulates ipsilateral inhibition.

Main Methods:

• Utilized between-hand choice reaction time tasks with manipulated response probability bias to alter error risk.
• Recorded electroencephalographic (EEG) waves over motor cortices (contralateral and ipsilateral).
• Analyzed surface Laplacian transforms of EEG signals to quantify motor cortex activity.

Main Results:

• Contralateral motor cortex activation remained unaffected by changes in error risk.
• Ipsilateral motor cortex inhibition demonstrated a graded response to error risk.
• Higher error risk correlated with significantly stronger ipsilateral motor cortex inhibition.

Conclusions:

• Ipsilateral motor cortex inhibition is an active, adaptive mechanism for error prevention during motor tasks.
• This neural inhibition scales with the perceived risk of making a mistake.
• Findings support a proactive role for the ipsilateral motor cortex in ensuring response accuracy.