Movement-related potentials and control of associated movements

Area of Science:

• Neuroscience
• Motor Control Research
• Human Movement Science

Background:

• The readiness potential (RP) preceding motor acts is linked to motor control.
• Increased positivity in RP components correlates with greater extraneous eye movements (EM), suggesting less motor control.
• Previous research indicates a potential role for RP positivity in inhibiting extraneous movements, particularly in younger individuals.

Purpose of the Study:

• To investigate the relationship between motor control, associated movements (AM), and the readiness potential (RP).
• To explore the hypothesis that positive RP components reflect motor inhibition processes.
• To examine the influence of age on motor control and RP characteristics.

Main Methods:

• A novel finger lift task was designed to detect irrelevant associated movements (AM) from both the responding and non-responding hands.
• Trials were categorized into associated movement (AM) trials and no associated movement (NAM) trials.
• Difference waveforms were analyzed, comparing RP components between AM and NAM trials.

Main Results:

• A positive-going shift in the RP was observed on trials with discrete target finger movements (NAM) compared to AM trials.
• A significant correlation was found between age and RP positivity in ipsilateral and posterior brain regions.
• RP positivity appears to be confounded by an overlapping slow positivity on trials where associated movements are successfully inhibited.

Conclusions:

• Successfully inhibiting associated movements during motor tasks is associated with a positive shift in the readiness potential (RP).
• This positivity may reflect the neural effort required for inhibiting extraneous movements to achieve a discrete motor response.
• The findings highlight a functional link between motor control, age, and the neural processes underlying movement inhibition, as reflected in the RP.