Prefrontal FGF1 Signaling is Required for Accumbal Deep Brain Stimulation Treatment of Addiction

Deep brain stimulation (DBS) has emerged as a prospective treatment for psychiatric disorders; for example, DBS targeting the nucleus accumbens (NAc) abolishes addictive behaviors. However, neither the core pathway nor the cellular mechanisms underlying these therapeutic effects are known. Here, morphine-induced conditioned place preference (CPP) in mice as an addiction model and NAc-DBS combined with adeno-associated virus gene delivery for activity-dependent tagging, transgenic and chemogenetic manipulation of recruited neuronal networks are used. It is reported that a cortical-accumbal pathway and local fibroblast growth factor 1 (FGF1) signaling in the medial prefrontal cortex (mPFC) are critical for NAc-DBS to be effective in altering morphine CPP. It is shown that NAc-DBS retrogradely activates mPFC neurons projecting to the NAc, and chemogenetic activation/inhibition of these DBS-activated neuron ensembles in the mPFC reproduces the NAc-DBS effects on CPP. Sustained therapeutic effects accompany reductions in local FGF1 binding to fibroblast growth factor receptor 1 (FGFR1) in these neurons. Additionally, overexpressing FGF1 in the mPFC-NAc pathway abolishes the therapeutic effects of NAc-DBS. These results demonstrate that the mPFC-NAc pathway forms a top-down motif to regulate the therapeutic effects of subcortical DBS on addiction. These results support the potential for addiction treatments involving FGF1 signaling and highlight the mPFC as a target for noninvasive brain stimulation.