Comparative Analysis of Motor Preparation Using Bereitschaftspotential With Two Methods of Wrist Extension

Motor control for voluntary movement involves the orchestrated activity of motor cortical areas, which activate approximately one to two seconds before movement onset. This preparatory neural activity, termed Bereitschaftspotential (BP), reflects the readiness of cortical circuits for initiating movement. BP has been linked to parameters such as force and rate of contraction; however, the influence of movement precision on BP components is less understood. This study aims to investigate how movement precision affects BP characteristics, providing insights into the neural dynamics underlying motor preparation.

Using a quasi-experimental design, BP characteristics were compared in 15 healthy, right-handed male participants (ages 40-60) under two conditions: precise wrist extensions (Method 1) and self-paced wrist extensions with relaxed precision (Method 2). BP was recorded at Cz, C3, and C4 electrodes, with electroencephalogram (EEG) data averaged from -3 seconds to +1 seconds relative to electromyogram (EMG) onset. Method 1 required controlled wrist extensions with visual feedback, while Method 2 permitted varied movement parameters. BP parameters analyzed included peak amplitude, early slope, late slope, and onset time, compared across the two methods using paired t-tests.

BP amplitude and slope were significantly greater during Method 1 than Method 2, particularly at the Cz and C3 sites. At Cz, all BP parameters were significantly higher in Method 1 compared to Method 2, including early slope (p = 0.0005), late slope (p = 0.0124), amplitude (p = 0.00003), and onset time (p = 0.0020). At C3, early slope (p = 0.0137), late slope (p = 0.0282), and amplitude (p = 0.0005) were significantly higher, while onset time showed no difference (p = 0.5823). At C4, only amplitude showed a significant difference (p = 0.034), with other parameters not reaching statistical significance. These findings indicate that Method 1, requiring precision, engaged motor cortical regions more intensively, particularly in preparatory neural activity.

This study highlights BP sensitivity to movement precision, with distinct BP features linked to precise motor tasks. BP monitoring could be valuable in neurorehabilitation, especially for conditions affecting motor preparation, such as Parkinson's disease and post-stroke patients. Future research may expand BP applications, emphasizing its potential as a biomarker for motor preparedness and precise motor control interventions.