The present study addresses the question of whether the anti-anhedonic effect of vmPFC-DBS is mediated by the brain reward system.
Rats of the Flinders Sensitive Line (FSL), a validated genetic animal model of depression, and its controls, the Flinders Resistant Line (FRL), were stimulated in the vmPFC and tested in the forced swim test (FST), sucrose consumption test (SCT) and the intracranial self-stimulation (ICSS) paradigm. The curve-shift paradigm of ICSS was used in combination with vmPFC-DBS, d-amphetamine and fluoxetine to quantify reward-facilitating or -attenuating treatment effects.
Our findings support anti-depressive efficacy of vmPFC-DBS with respect to despair- and anhedonia-like behavior, as shown in the FST and SCT, respectively. However, DBS did not elicit reward-facilitating or reward-attenuating effects on ICSS behavior.
These data suggest that it is unlikely that the anti-anhedonic effect of vmPFC-DBS depends on the mesolimbic dopaminergic reward system.