Binding potential variability connects to psychological variability

Interesting, ostensibly simple study: Buckholtz et al used PET (which is > fMRI, IMCO) on volunteers given amphetamine using a radio-labeled D2-like ligand, fallypride.  They found a significant inverse correlation (r = -0.42 and -0.35 for the left and right striatum) between average D2-like receptor binding potential (i.e. the density of “available” receptors) and striatal dopamine release after the introduction of amphetamines. They also found a significant positive correlation (r = 0.48 and 0.47 for the left and right striatum) between more dopamine release and increased subjective pleasure from amphetamine.

This research is often ballyhooed due to its applications to free will and law / politics, but I find it especially interesting from a strictly neuro perspective. What other areas of the brain use this ligand binding potential mechanism to transduce synaptic variability into psychological variability? Evolutionarily, it seems unlikely that this is the only such system.

Reference

Buckholtz JW, Treadway MT, Cowan RL, Woodward ND, Li R, Ansari MS, Baldwin RM, Schwartzman AN, Shelby ES, Smith CE, Kessler RM, Zald DH. 2010  Dopaminergic network differences in human impulsivity.  Science.