Foreperiod and Response Complexity Effects on Movement-Related Potentials.

Area of Science:

• Cognitive Neuroscience
• Motor Control
• Human Reaction Time

Background:

• A debate exists on whether warning signals improve reaction speed through motor preparation or execution.
• Previous studies have not fully clarified the role of warning signals in motor response modulation.

Purpose of the Study:

• To investigate if warning signals (WS) speed voluntary reactions by enhancing motor preparation and execution.
• To examine the influence of foreperiod duration on sensorimotor cortex activity during reaction time tasks.

Main Methods:

• Measured hand-specific sensorimotor cortex activity using the lateralized readiness potential (LRP).
• Employed localized current source density (surface Laplacian waves) to analyze cortical activity contralateral and ipsilateral to the response hand.
• Manipulated foreperiod duration between the WS and reaction stimulus.

Main Results:

• Foreperiod duration significantly influenced sensorimotor cortex activity, as indicated by LRP.
• Speeding of late motoric processes was observed when analyzing cortical activity with surface Laplacians.
• Findings were not fully explained by alternative hypotheses like CNV baseline correction or the aperture problem.

Conclusions:

• The study provides evidence that warning signals facilitate motor preparation and execution, resolving a key debate in attention and action literature.
• Surface Laplacians offer a valuable method for observing late motoric process facilitation, particularly in sequential responses.
• The findings highlight the complex interplay between attention, preparation, and motor execution in voluntary reactions.