Chronic alcohol regulates circuitry structure and demand for alcohol

点击翻译按钮获取中文摘要

PROJECT SUMMARY We endeavor to drive new approaches to understand the effect of alcohol on the brain by establishing fresh mechanisms of action for alcohol exposure on dysregulating novel neurocircuitry. A candidate circuit altered by alcohol exposure is the downstream synaptic connectivity of the glutamatergic orbitofrontal cortex (OFC) to nucleus accumbens (NAc) pathway. The goal of this project is to establish that downstream connectivity of glutamatergic neurons from the OFC to the NAc are altered by repeated alcohol exposure, which modulates alcohol-driven behavior via dopamine receptor 1- expressing neurons projecting to the ventral tegmental area (VTA). In this proposal, we will investigate the neuroanatomical connectivity of the OFC → NAc pathway in the context of alcohol exposure. Our observations suggest that the OFC → NAc pathway exhibits downstream connectivity with the VTA of the accumbal direct pathway. This project is based upon the premise that repeated alcohol exposure will increase excitatory drive of the glutamatergic OFC → NAc pathway onto D1- expressing NAc → VTA to potentiate motivational effects of alcohol. We hypothesize that repeated alcohol exposure increases the synaptic connectivity of glutamatergic OFC projections onto D1-expressing NAc to VTA pathway neurons with concomitant increases in alcohol intake. We will test this hypothesis with the following specific aims: 1) Define the structural linkage within the OFC → NAc → VTA circuit after repeated alcohol consumption; and 2) Uncover the behavioral effect of repeated alcohol exposure on alcohol self-administration. To realize our Aims, we will employ contemporary strategies such as behavioral economics and transsynaptic neuroanatomical tracing to detail connectivity through three separate brain regions. Together, the proposed research will examine alcohol-evoked changes in connectivity as a mechanism that underlies increases in alcohol taking. Overall, these studies will impact the field by furthering our knowledgebase for understanding how previous alcohol exposure alters brain circuit connectivity to potentiate future alcohol consumption.