Effects of reaction time variability and age on brain activity during Stroop task performance

Area of Science:

• Neuroscience
• Cognitive Psychology
• Aging Research

Background:

• Variability in reaction time (RT) can indicate attention fluctuations and impact task performance.
• It remains unclear if the neural mechanisms of RT variability change with age.

Purpose of the Study:

• To investigate age-related differences in the neural mechanisms of intra-individual RT variability.
• To determine if brain activity patterns associated with RT variability differ between young and older adults.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan young and cognitively healthy older adults.
• Participants completed the Stroop task to assess cognitive control and RT.

Main Results:

• Significant differences in Blood-Oxygen-Level-Dependent (BOLD) activity modulated by RT were observed between age groups.
• In older adults, longer RTs correlated with increased activity in frontoparietal attentional networks.
• In younger adults, longer RTs correlated with increased activity in default mode network (DMN) areas.

Conclusions:

• The neural correlates of RT variability shift with healthy aging.
• Findings support the concept of functional plasticity in maintaining cognitive function across the lifespan.