Recently, data have become publicly available via BrainCloud on gene transcript expression in the dorsolateral prefrontal cortex of human postmortem brain samples across the lifespan (download available at http://braincloud.jhmi.edu/) (Colantuoni et al., 2011). We examined BrainCloud for the pattern of DRD1 expression across development. Similar to what has been described regarding DRD1 expression in rat prefrontal cortex (Andersen et al., 2000), there appears to be a nonlinear pattern of DRD1 expression in human dorsolateral prefrontal cortex that climbs in childhood and adolescence, peaks in early adulthood/early 20s, and then tails off over the course of later life (Figure S5 in Supplementary Materials). Even though this is an indirect observation, this pattern of DRD1 gene transcript expression across the lifespan could be relevant to the results of the current study given that our strongest effects did not emerge until late adolescence/early adulthood, and because the SNPs that we examined are putatively associated with differences in DRD1 expression (Huang et al., 2008).
