Poster B109, Sunday, March 25, 8:00-10:00 am, Exhibit Hall C
Reliability of the Correlative Triad among Aging, Dopamine, and Cognition
Eric J. Juarez1, Jaime J. Castrellon1, Mikella A. Green1, Galen A. McAllister1, Kendra L. Seaman1, Christopher T. Smith2, Linh C. Dang2, David H. Zald2, Gregory R. Samanez-Larkin1; 1Duke University, 2Vanderbilt University
The evidence that dopamine receptor availability mediates the association between aging and cognition is one of the most widely cited findings in the cognitive neuroscience of aging. However, relatively few studies have directly examined these associations. Most of these studies have very small sample sizes and results have been inconsistent. Here we examined correlations among adult age, dopamine receptor availability, and cognition in a sample of eighty-three healthy adults (ages 22–83, M=50, SD=18). Subjects completed a short neuropsychological test battery (delayed recall from verbal paired associates, digit span, letter-number sequencing, trail-making test) and, on a separate day, a PET scan with the high-affinity D2-like receptor tracer [18F]fallypride. Digit span was the only variable for which the measure of dopamine receptor availability mediated the age effect on cognitive performance. Age was negatively correlated with digit span (r=–.27). Striatal receptor availability was positively correlated with digit span controlling for age (r=.29). The age effect on digit span was reduced (r=–.27 to r =–.13) when controlling for striatal receptor availability. Although the other cognitive measures used here have been individually associated with both age and dopaminergic variables in prior studies, we found no evidence for significant associations between D2 receptors and cognitive performance on these measures using either ROI-based or whole-brain analyses. Overall, the results partially support the correlative triad of age, D2 receptors, and cognition, with evidence that some previously reported D2-cognition associations may not be as reliable.
Topic Area: THINKING: Development & aging