Executive functions gradually improve over one’s life and are crucial for supporting advanced thinking in a variety of domains. We have shown that there are larger age-related differences in the brain for response inhibition than for visual search, and have suggested that this is due to slower maturation of the frontal lobes critical for executive functioning. In addition to inhibitory processes, working memory is a core executive function involved in many aspects of academics. We have examined the role of domain general working memory in forming verbal and quantity representations. Higher verbal working memory is associated with more robust activation of verbal mechanisms for multiplication. In contrast, higher spatial working memory is correlated with greater engagement of quantity mechanisms for subtraction. These findings suggest that working memory is crucial for solidifying cortical representations for academic skills. We are currently examining whether the neural correlates of working memory predict gains in math and reading.
We have also shown that children with attention deficit hyperactivity disorder (ADHD) exhibit larger brain abnormalities for response inhibition than for visual search, suggesting that a central deficit in ADHD is executive function. Our more recent work tested whether altering the context of the executive function task enhanced behavioral and brain function in children with ADHD. We used an innovative task design to orthogonally manipulate both reward size and the presence or absence of feedback during a working memory task. We found that there was a normalization of behavior and frontal activation only when children with ADHD performed the working memory task under large reward conditions in the presence of feedback. This is consistent with some of our other work showing the benefits of feedback learning compared to observational learning. Using classification algorithms to ‘diagnose’ ADHD children with this ensemble of tasks, we obtained over 90% specificity and sensitivity, opening up the way for an objective biomarker of ADHD. Our future work will determine whether we can use these diagnostic algorithms to distinguish between ADHD and learning disabilities to determine domain specific versus general mechanisms.