Altered executive function in the lead-exposed brain: A functional magnetic resonance imaging study

• We used fMRI scans with Wisconsin Card Sorting Task to assess possible alterations in the neural correlates of executive function in the previously lead-exposed brain.
• The neural activation of left dorsolateral prefrontal cortex was greater in healthy controls than in participants with lead exposure.
• Cortical activation was inversely associated with blood lead concentration.

IntroductionIt is well known that lead exposure induces neurotoxic effects, which can result in dysfunction in a variety of cognitive capacities including executive function. However, few studies have used fMRI to examine the direct neural correlates of executive function in participants with past lead exposure. Therefore, this study aimed to investigate possible alterations in the neural correlates of executive function in the previously lead-exposed brain.MethodsForty-three lead-exposed and 41 healthy participants were enrolled. During the fMRI scans, participants performed two modified versions of the Wisconsin Card Sorting Task (WCST) differing in cognitive demand, and a task that established a high-level baseline condition (HLB).ResultsThe neural activation of left dorsolateral prefrontal cortex was greater in healthy controls than in participants with lead exposure when contrasting the difficult version of the WCST with the HLB. Moreover, cortical activation was found to be inversely associated with blood lead concentration after controlling for covariates.DiscussionThese data suggest that lead exposure can induce functional abnormalities in distributed cortical networks related to executive function, and that lead-induced neurotoxicity may be persistent rather than transient.