Motor Preparation Disrupts Proactive Control in the Stop Signal Task

Area of Science:

• Neuroscience
• Cognitive Psychology
• Computational Neuroscience

Background:

• The stop signal task (SST) assesses response inhibition, with proactive control influencing performance.
• Sequential effects, like prolonged reaction times on go trials following a stop signal, indicate proactive control.
• Individual differences exist in sequential effects, suggesting varied impacts of motor preparation on proactive control.

Purpose of the Study:

• To investigate how motor preparation influences proactive control and response inhibition.
• To compare neural mechanisms underlying these processes in individuals with and without sequential effects.

Main Methods:

• Bayesian modeling to estimate stop signal likelihood (P(Stop)) trial-by-trial.
• Analysis of brain activations and Granger causal connectivities using fMRI data.
• Comparison between groups with (SEQ) and without (nSEQ) sequential effects.

Main Results:

• No differences in regional brain activations related to conflict anticipation or motor preparation between SEQ and nSEQ groups.
• Distinct Granger causal connectivity patterns observed between SEQ and nSEQ groups.
• In SEQ, P(Stop) and fore-period (FP) activations showed reciprocal influence; in nSEQ, FP unidirectionally influenced P(Stop) and goRT speeding.

Conclusions:

• Motor preparation disrupts proactive control in individuals without sequential effects (nSEQ).
• Findings provide neural evidence for interactive go and stop processes, modulated by individual differences in motor preparation.