Ethanol and Persistent Activity in Prefrontal Cortex

酒精中毒的特点是对饮酒失去控制，这可能是由于长期的改变， 通常控制强迫行为的高级皮层回路脑成像研究表明，在 酗酒者，前额叶皮层（PFC）显示功能的改变，在禁欲或暴露后， 乙醇（EtOH）或与饮酒相关的视觉线索。然而，很少有人知道乙醇的作用 在细胞水平上对前额叶功能的影响在这个项目中，我们将调查急性和慢性的影响， 乙醇暴露对前额叶皮层兴奋性锥体神经元功能的影响。的标志 前额叶皮层神经元是“持续活动”，其特征是自发和有节奏的转换 在其中抑制放电的超极化向下状态和其中促进放电的去极化向上状态之间 来产生动作电位。兴奋期的放电活动受多巴胺能神经元的调节， 来自VTA神经元的输入，VTA神经元与第V层前额叶皮质神经元形成突触。持续的活动可能会让 前额叶皮层通过整合和整合对成瘾神经回路施加更高级的控制， 处理来自内部和外部线索的感官信息。持续活动中断 前额叶皮层内的EtOH状态可能是一个主要事件，在控制的强迫性 饮酒行为。已经在麻醉的整个动物中研究了持续的活性，但它不会发生 在简化的系统中，如急性分离的皮层切片。为了规避与以下方面相关的问题， 麻醉，并允许精确分析假定的机制，我们已经采用了切片共培养 包括前额叶皮层、腹侧被盖区和海马体。培养2周后， 该系统显示出可由刺激诱发的持续活动调节的鲁棒的和可再现的模式 腹侧被盖区多巴胺神经元放电该项目的主要目标是确定急性 和慢性乙醇暴露对PFC神经元持续活动的影响。目标1、2 和3将使用膜片钳电生理学来分析急性和慢性乙醇对 自发和VTA诱发的V层前额叶锥体神经元的持续活动。目标4将使用 共聚焦成像技术，以评估乙醇对锥体细胞活性在网络水平的影响。 这些研究的结果将产生关于乙醇对大脑功能影响的重要新信息。

Alcoholism is characterized by a loss of control over drinking that may result from long-lasting alterations in higher cortical circuits that normally control compulsive behaviors. Brain imaging studies show that, in alcoholics, the prefrontal cortex (PFC) displays functional alterations during abstinence or after exposure to ethanol (EtOH) or visual cues associated with drinking. Little, however, is known about the actions of EtOH on prefrontal function at the cellular level. In this project, we will investigate the effects of acute and chronic EtOH exposure on the function of excitatory pyramidal neurons of the prefrontal cortex. A hallmark of prefrontal cortical neurons is "persistent activity" characterized by spontaneous and rhythmic transitions between a hyperpolarized down-state in which firing is inhibited and a depolarized up-state that is conducive for generating action potentials. The firing activity during up-state periods is modulated by dopaminergic input from VTA neurons that synapse on layer V prefrontal cortical neurons. Persistent activity may allow the prefrontal cortex to exert higher-order control over the addiction neurocircuitry by integrating and processing sensory information derived from internal and external cues. Disruption of persistent activity states within the prefrontal cortex by EtOH may be a primary event in the loss of control over compulsive drinking behaviors. Persistent activity has been studied in anesthetized whole animals but it does not occur in reduced systems such as acutely isolated slices of cortex. To circumvent problems associated with anesthesia and to allow for precise analysis of putative mechanisms, we have adapted a slice co-culture system containing prefrontal cortex, VTA, and hippocampus. After 2 weeks in culture, prefrontal neurons in this system display robust and reproducible patterns of persistent activity that can modulated by stimulusevoked firing of VTA dopamine neurons. The major goal of this project is to determine the effects of acute and chronic ethanol exposure on persistent activity of PFC neurons using this co-culture system. Aims 1, 2 and 3 will use patch-clamp electrophysiology to analyze the effects of acute and chronic ethanol on spontaneous and VTA-evoked persistent activity in layer V prefrontal pyramidal neurons. Aim 4 will use confocal imaging techniques to assess the effects of ethanol on pyramidal cell activity at the network level. The results of these studies will yield important new information regarding ethanol's effects on brain function.