Novel Approaches to the Study of Single-Trial Learning

描述(申请人提供)：神经科学的一个主要努力是阐明大脑储存通过学习获得的信息的机制。为了在完全理解记忆形成方面取得进展，允许实验者将特定突触的变化与特定行为联系起来的模型系统是必不可少的。我们建议研究一种信息素记忆模型，该模型非常适合集成从分子到行为的几个层次的分析。雌性小鼠在交配过程中通过单次尝试学习形成对雄性信息素的记忆，并在其一生中的很长一段时间内保留这些信息。只有当两种神经递质输入谷氨酸和去甲肾上腺素(NE)在信息素记忆的副嗅球(AOB)重合时，记忆的形成才会发生。谷氨酸和去甲肾上腺素以某种方式导致AOB突触的结构和功能改变。我们的总体目标是了解谷氨酸和NE的重合是如何被检测到的，并阐明谷氨酸和NE下游控制长期信息素记忆形成的信号机制。我们的初步结果表明，蛋白激酶C(PKC)具有重要的信号转导作用。我们的第一个目标是使用一种新的方法，在电生理实验中使用特定的PKC亚型的激活剂和抑制剂，并结合生化实验来识别在AOB中检测到一致的谷氨酸和NE输入的PKC亚型。我们的第二个目标是开发一种方法，通过病毒介导的小干扰RNA传递来击倒特定PKC亚型的表达。拟议中的实验将启动一项研究计划，该计划具有巨大的潜力来解决与哺乳动物长期记忆有关的悬而未决的问题。在信息素记忆模型中，神经回路被很好地描绘出来，行为输出是明确的，遗传操作可以很容易地完成。因此，在将特定突触的分子变化与特定行为的变化联系起来方面，该模型系统具有其他系统无法比拟的优势。阐明突触可塑性的调控机制将有助于发现创伤后应激障碍、精神分裂症和阿尔茨海默病等异常疾病中记忆缺陷和认知功能障碍的原因，并有助于制定治疗策略。

DESCRIPTION (provided by applicant): A major endeavor in neuroscience is to elucidate the mechanisms by which the brain stores information acquired through learning. To make progress towards a complete understanding of memory formation, model systems that allow the experimenter to relate changes in specific synapses to specific behavior are essential. We propose to study a pheromone memory model that is ideally suited for integrating several levels of analysis: from molecules to behavior. Female mice form memory to the male's pheromones during mating through single-trial learning and retain the information for a significant period of their lifetime. The memory formation occurs only if two neurotransmitter inputs, glutamate and norepinephrine (NE), coincide in the accessory olfactory bulb (AOB), the locus of pheromone memory. Glutamate and NE somehow lead to structural and functional modifications of the AOB synapses. Our overall goal is to understand how coincidence of glutamate and NE is detected, and to elucidate the signaling mechanisms downstream of glutamate and NE that control formation of long-term pheromone memory. Our preliminary results suggest that protein kinase C (PKC) has a critical signaling role. Our first aim is to use a novel approach that uses specific activators and inhibitors of PKC isoforms in electrophysiological experiments in combination with biochemical experiments to identify the isoform of PKC that detects coincident glutamate and NE inputs in the AOB. Our second aim is to develop a method to knock down the expression of a specific PKC isoform via virally-mediated delivery of small interfering RNAs. The proposed experiments would launch a research program that has enormous potential to address unanswered questions pertaining to mammalian long-term memory. In the pheromone memory model the neural circuitry is well delineated, the behavioral output is unambiguous, and genetic manipulations can be readily done. Therefore, this model system has unparalleled advantages over other systems in linking molecular changes in a specific synapse to changes in a specific behavior. Clarification of the mechanisms governing synaptic plasticity would be beneficial for discovering the causes of memory deficits and cognitive dysfunctions that occur in abnormalities like posttraumatic stress disorder, schizophrenia and Alzheimer's disease, and for devising therapeutic strategies.