RT Journal Article
SR Electronic
T1 Reproducibility of the correlative triad among aging, dopamine receptor availability, and cognition
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 494765
DO 10.1101/494765
A1 Eric J. Juarez
A1 Jaime J. Castrellon
A1 Mikella A. Green
A1 Jennifer L. Crawford
A1 Kendra L. Seaman
A1 Christopher T. Smith
A1 Linh C. Dang
A1 David Matuskey
A1 Evan D. Morris
A1 Ronald L. Cowan
A1 David H. Zald
A1 Gregory R. Samanez-Larkin
YR 2019
UL http://biorxiv.org/content/early/2019/07/31/494765.abstract
AB The evidence that dopamine function mediates the association between aging and cognition is one of the most cited findings in the cognitive neuroscience of aging. However, few and relatively small studies have directly examined these associations. Here we examined correlations among adult age, dopamine D2-like receptor (D2R) availability, and cognition in two cross-sectional studies of healthy human adults. Participants completed a short cognitive test battery and, on a separate day, a PET scan with either the high-affinity D2R tracer [18F]Fallypride (Study 1) or [11C]FLB457 (Study 2). Digit span, a measure of short-term memory maintenance and working memory, was the only cognitive test for which dopamine D2R availability partially mediated the age effect on cognition. In Study 1, age was negatively correlated with digit span. Striatal D2R availability was positively correlated with digit span controlling for age. The age effect on digit span was smaller when controlling for striatal D2R availability. Although other cognitive measures used here have individually been associated with age and D2R availability in prior studies, we found no consistent evidence for significant associations between low D2R availability and low cognitive performance on these measures. These results at best only partially supported the correlative triad of age, dopamine D2R availability, and cognition. While a wealth of other research in human and non-human animals demonstrates that dopamine makes critical contributions to cognition, the present studies suggest caution in interpreting PET findings as evidence that dopamine D2R loss is a primary cause of broad age-related declines in fluid cognition.