Reward anticipation modulates primary motor cortex excitability during task preparation

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Motor Control

Background:

• Task preparation involves transient suppression of corticospinal excitability (CSE).
• The influence of motivational factors, such as reward anticipation, on CSE suppression during preparation remains unclear.

Purpose of the Study:

• To investigate if reward anticipation modulates CSE suppression during task preparation.
• To determine how this modulation develops over time.

Main Methods:

• A cue-target delay paradigm was used with a Simon task.
• Single-pulse transcranial magnetic stimulation (TMS) assessed CSE during the delay period (400, 600, 800ms post-cue) and post-target.
• Electromyography (EMG) recorded muscle activity.

Main Results:

• Behaviorally, reward anticipation led to faster reaction times.
• A linear decrease in motor evoked potential (MEP) amplitudes was observed during reward anticipation.
• This MEP amplitude decrease was absent when no reward was anticipated.

Conclusions:

• Reward anticipation significantly modulates corticospinal excitability during task preparation.
• Motivational states influence the neural mechanisms underlying motor preparation and control.