Dorsolateral prefrontal cortex volume as a mediator between socioeconomic status and executive function

Area of Science:

• Neuroscience
• Cognitive Psychology
• Sociology

Background:

• Socioeconomic status (SES) is associated with cognitive deficits.
• The neural mechanisms linking SES to cognitive function require further elucidation.
• Existing research suggests race may influence SES-brain relationships.

Purpose of the Study:

• To investigate if dorsolateral prefrontal cortex (DLPFC) volume mediates the relationship between SES and executive function.
• To examine if this mediation differs across racial groups (African American and White adults).

Main Methods:

• 190 diverse adults (African American and White) from the HANDLS SCAN study were analyzed.
• Regional brain volumes were assessed using MRI (T1-weighted MP-RAGE).
• Moderated mediation analyses examined the role of DLPFC in SES-executive function links, controlling for age and sex. Executive functions measured included Trail Making Test B, Digit Span Backwards, and verbal fluency.

Main Results:

• DLPFC volume significantly mediated the SES-Trails B association in White adults.
• This mediation was not significant in African American adults.
• While SES correlated with all executive function tests, DLPFC mediation was specific to Trails B in White participants.

Conclusions:

• Dorsolateral prefrontal cortex volume may be crucial for the SES-mental flexibility link in White adults, but not African American adults.
• The cognitive benefits of higher SES observed in White populations may not generalize to African American populations.
• Findings underscore the role of brain volume in cognitive function and highlight sociodemographic disparities in health.