Span capacity and age-related differences in prefrontal functional organization during visual discrimination

Area of Science:

• Cognitive neuroscience
• Neuroimaging
• Aging research

Background:

• Aging is associated with altered prefrontal cortex (PFC) recruitment, often involving posterior-anterior shifts.
• Working memory capacity (WMC) is crucial for attention and control, but its role in age-related brain reorganization is not fully understood.

Purpose of the Study:

• To investigate the relationship between working memory capacity (WMC) and brain activity across the adult lifespan.
• To examine how WMC influences functional reorganization in the aging brain during demanding cognitive tasks.

Main Methods:

• fMRI (functional Magnetic Resonance Imaging) was used to scan 72 adults (36 younger, 36 older) performing a visual discrimination task.
• Participants completed standardized span tasks to assess WMC.
• Analyses explored age-group differences in WMC-brain associations, controlling for sex and education.

Main Results:

• WMC correlated with cognitive efficiency, particularly under high-demand conditions.
• In younger adults, higher simple span linked to posterior parietal/occipitotemporal activity; higher complex span linked to dorsolateral/anterior PFC activity during task switching.
• Older adults with higher complex span showed increased engagement of frontal pole and inferior frontal regions, suggesting compensatory brain recruitment.

Conclusions:

• Working memory capacity (WMC) significantly shapes brain activity patterns related to cognitive control across the lifespan.
• Age-related functional reorganization in the brain may involve compensatory recruitment in frontal regions, influenced by WMC.