Cerebral potentials preceding unilateral and simultaneous bilateral finger movements

Area of Science:

• Neuroscience
• Motor Control
• Electrophysiology

Background:

• The Bereitschaftspotential (BP) is a well-studied electrophysiological signal preceding voluntary movement.
• Previous research has primarily focused on unilateral movements, with less known about bilateral simultaneous movements.
• Understanding hemispheric involvement in bilateral movements is crucial for comprehending motor control.

Purpose of the Study:

• To investigate cerebral potentials, specifically the Bereitschaftspotential (BP) and pre-motion positivity (PMP), preceding voluntary bilateral simultaneous finger movements.
• To compare these potentials with those recorded during unilateral finger movements.
• To analyze hemispheric asymmetries and timing differences in motor-related potentials.

Main Methods:

• Electrophysiological recordings (EEG) of cerebral potentials (BP, PMP, MP) from 19 right-handed subjects.
• Simultaneous electromyography (EMG) of finger muscles.
• Comparison of potentials during bilateral and unilateral (right-sided) finger movements.

Main Results:

• The BP was significantly larger over the minor (left) hemisphere compared to the dominant (right) hemisphere during bilateral movements.
• The pre-motion positivity (PMP) was more developed and larger during bilateral movements than unilateral movements.
• The motor potential (MP) was larger during unilateral movements, and EMG showed earlier muscle contraction in the right hand and abortive mirror activity in the non-moving left hand during unilateral movements.

Conclusions:

• Bilateral finger movements involve a surprising asymmetry in BP generation, with greater activity in the minor hemisphere.
• The PMP is enhanced during bilateral movements, suggesting a role in coordinating simultaneous actions.
• These findings provide new insights into the neural control of bilateral motor tasks and hemispheric specialization.