Credit: University of Michigan, Flagel lab
In these images of rat brains, differences in gene expression of genes for fibroblast growth factor 2 (FGF2, top set) and dopamine 2 receptor (D2, bottom sett) can be seen in rats of two breeds before (left) and after (right) cocaine exposure. The addiction-prone bHR rats differed significantly in several ways from the timid bLR rats.