Functional localization and mechanisms of sequential effects in serial reaction time tasks

Area of Science:

• Cognitive psychology
• Neuroscience
• Human information processing

Background:

• Reaction times (RTs) are modulated by preceding events, exhibiting cost-only or cost-benefit patterns.
• Understanding the neural basis of sequential effects is crucial for localizing cognitive processes.

Purpose of the Study:

• To investigate the neural mechanisms underlying sequential effects on reaction times.
• To differentiate the impact of sequential event patterns on premotoric versus motoric processing stages.

Main Methods:

• Participants performed tasks with induced sequential event patterns.
• Reaction times (RTs) and lateralized readiness potential (LRP) onsets were analyzed.
• LRP amplitude developments across trials were examined to identify residual trace accumulation.

Main Results:

• Analysis of RTs and LRPs indicated residual trace accumulation as a mechanism for sequential effects.
• Trace accumulation in premotoric stages resulted in consistent cost-benefit patterns.
• In motoric stages, trace accumulation primarily benefited event repetitions, with no associated costs for discontinuations.

Conclusions:

• Sequential effects on RTs are mediated by residual trace accumulation in distinct processing stages.
• Premotoric stages exhibit flexible cost-benefit adjustments based on event sequences.
• Motoric stages show more rigid processing, benefiting primarily from predictable event repetitions.