Loss of Inhibitory Control in Alcohol Seeking and Dependence: Role of Thalamostriatal Circuitry

项目摘要 适应不良的酒精寻求，酒精使用障碍（AUD）的一个标志，被认为不仅是由 增加神经回路的功能，驱动自然的奖励寻求，但也失去了控制的电路 用来抑制与安全和生存不相容的行为。后室旁丘脑， pPVT及其向丘脑核（NAc）的投射提供了对多巴胺的前馈抑制。 表达受体的中型多刺神经元（MSN），主要负责促进奖励， 动机行为。刺激和情况，自然有助于限制适应不良的行为，如行为 威胁，已被证明可以激活这些pPVT®NAc投射神经元，并通过 下游小清蛋白抑制性中间神经元（PV-IN）的激活。我们的实验室显示急性 应激源（TMT捕食者气味）、乙醇奎宁掺杂和pPVT®NAc电路的光遗传学激活 减少奖励-以及对该提议特别重要的是，非依赖性小鼠的酒精寻求。 此外，我们发现，这种回路的能力，以挑起行为抑制后，失去了诱导 酒精依赖这些行为适应与pPVT®NAc的突触功效降低平行 酒精依赖小鼠中下游PV-IN上的神经元能突触。我们的数据表明，对于 第一次，pPVT®NAc投射神经元负责抑制酒精寻求 行为，但由于长期酒精暴露而失调。我们正式测试独立的组件， 三个独立的目标。在目标1中，使用双光子钙成像，我们将测量和 纵向跟踪酒精期间pPVT®NAc投射和NAc PV-IN中的神经元系综动力学 在非依赖性和依赖性小鼠中进行自我给药、消耗和行为抑制试验。目的 2将探讨慢性酒精暴露对pPVT突触的内在和突触适应的影响， 使用切片电生理学，将输入输入到NAc中的PV-IN和MSN。最后，在目标3中，我们将确定 激活pPVT®NAc输入和/或激活NAc中的PV-IN是否足以恢复 前馈抑制和控制非依赖性与依赖性小鼠中的酒精寻求。该项目将确定 一个主要但未被充分研究的奖励回路的活动是如何从饮酒开始到 并将进一步确定这种活动如何影响酒精的表达和抑制 寻找

PROJECT SUMMARY Maladaptive alcohol seeking, a hallmark of alcohol use disorder (AUD), is thought to be driven not only by increased function of neural circuitry that drives natural reward seeking, but also by loss of control of circuitry that serves to suppress behaviors incompatible with safety and survival. The posterior paraventricular thalamus, (pPVT), and its projections to the nucleus accumbens (NAc), provide feedforward inhibition onto dopamine receptor-expressing medium spiny neurons (MSNs) which are largely responsible for promoting reward- motivated behaviors. Stimuli and situations that naturally serve to limit maladaptive behaviors, such as behavioral threats, have been shown to activate these pPVT®NAc projection neurons and suppress behavior through the activation of downstream parvalbumin inhibitory interneurons (PV-INs). Our labs have shown that an acute stressor (TMT predator odor), quinine-adulteration of alcohol and optogenetic activation of pPVT®NAc circuitry reduces reward- and, of particular importance to this proposal, alcohol-seeking in non-dependent mice. Furthermore, we show that the ability of this circuit to provoke behavioral inhibition is lost after the induction of alcohol dependence. These behavioral adaptations parallel reduced synaptic efficacy at pPVT®NAc glutamatergic synapses onto downstream PV-INs in alcohol-dependent mice. Our data therefore suggest, for the first time, that pPVT®NAc projection neurons are responsible for the suppression of alcohol-seeking behavior but are dysregulated by chronic alcohol exposure. We formally test independent components of this hypothesis in three independent Aims. In Aim 1, using two-photon calcium imaging we will measure and longitudinally track neuronal ensemble dynamics in both pPVT®NAc projections and NAc PV-INs during alcohol self-administration, consumption, and tests of behavioral inhibition in non-dependent and dependent mice. Aim 2 will explore the effects of chronic alcohol exposure on intrinsic and synaptic adaptations in pPVT synaptic inputs to both PV-INs and MSNs in the NAc using slice electrophysiology. Lastly, in Aim 3 we will determine whether activation of pPVT®NAc inputs and/or activation of PV-INs in the NAc are sufficient to restore feedforward inhibition and control alcohol-seeking in non-dependent vs. dependent mice. This project will identify how activity in a principal – but understudied – reward circuit changes from the onset of alcohol use to dependence and will further determine how this activity influences the expression and suppression of alcohol seeking.