Here, we completed two studies to address these issues. Experiment 1 utilized FSCV alone to examine if differences are observed in rapid dopamine release dynamics in the core versus shell during cocaine self-administration. In Experiment 2, we examined the relationship of rapid dopamine signaling to NAc cell firing during the same task using simultaneous voltammetric and electrophysiological recordings from the same electrode. We found that dopamine is released within seconds of the cocaine-reinforced response in both the core and shell, however differences were observed in the temporal properties of rapid dopamine signaling across sub-regions relative to the response. Additionally, at certain sites within both sub-regions, neurons exhibiting patterned activation were observed at locations where behavior-related rapid dopamine release was present; no changes in dopamine concentration were observed where nonphasic neurons were recorded. These findings reveal that dopamine release within each sub-region is heterogeneous and varies as a function of ongoing drug-seeking behavior and precise neuronal targets in the NAc.
