Corticostriatal networks and NMDAR mediation of habitual and flexible action

描述（由申请方提供）：小鼠中习惯性和灵活性动作的皮质纹状体网络和NMDAR介导。 这项研究的目的是研究调节习惯性和灵活性行为平衡的神经回路，这种平衡被认为在酒精依赖中发生了功能障碍。虽然在其他物种的研究提供了强有力的证据，这些行为是由连接皮层和纹状体亚区的网络介导的，但这在小鼠中还没有得到很好的证实。为了使酒精研究充分利用小鼠模型所允许的分子和遗传技术，必须首先确定这些回路在该物种中的作用。我建议阐明的网络和分子机制的基础上的习惯和灵活的行动，在小鼠中使用一种综合的方法，结合传统的技术（病变和微输注）与新兴的遗传和电生理技术。为了做到这一点，我提出了三个具体的目标1）确定参与皮质纹状体网络和NMDAR介导的良好的学习和灵活的行为在小鼠。为了实现这一目标，我建议映射内源性激活模式，并检查子区域特定病变的小鼠执行的任务，需要习惯性和灵活的行动：视觉歧视和逆转的影响。此外，将使用条件性GluN2B突变小鼠模型测试皮质纹状体亚区中NMDAR亚基缺失对习惯性和灵活性表现的影响。2.检查在体皮质纹状体网络的电生理活动和NMDAR在良好学习和灵活行为中的作用。为了实现这一目标，我建议在非突变小鼠和GluN2B条件突变模型的歧视逆转任务的执行过程中，在皮层和纹状体亚区的神经元活动进行体内记录。3.在执行控制的高阶测量中检查皮质纹状体网络的体内电生理活动。为了完成这一目标，我建议在非突变和GluN2B突变小鼠中进行电生理记录，这些小鼠执行直接适应于用于测量临床人群中的执行控制的操作性任务：视觉设置转换。总之，这些具体目标的完成将提供强有力的证据，皮质纹状体网络和NMDAR在调解灵活和习惯性的行动的作用，并为未来的研究提供了一个坚实的基础，调查这些系统是如何在酒精滥用和依赖失调。 在我的研究生培训和奖学金期间，我开发了必要的科学设计和行为的知识，以完成在拟议的实验中取得成功所必需的指导培训和开发。作为Lawrence Rothblat博士实验室的研究生，我接受了使用转基因和突变小鼠模型进行操作性行为任务的神经科学研究的设计和实施基础的培训，并获得了立体定位外科手术和组织学技术的经验。Andrew Holmes博士的指导下，我接受了广泛的实践培训，包括广泛的行为测量和各种急性和慢性全身药物管理技术，以及用于蛋白质印迹和高压液相色谱的组织显微解剖。此外，我还扩展了他的外科技术，包括在清醒行为动物中植入留置导管和微量输注生物活性药物。 该提案的指导阶段将在NIAAA的校内临床和生物学研究部门进行，由Andrew Holmes博士和大卫Lovinger博士共同指导。Holmes博士在行为神经科学技术方面拥有广泛的专业知识，并拥有一个完善的研究计划，使用行为范式来研究遗传和环境因素，这些因素是使用小鼠模型成瘾和神经病理学的基础。Lovinger博士是使用体内和体外电生理学研究酒精和药物滥用靶点的领导者。该环境将提供完成研究目标所需的所有必要资源，包括但不限于行为仪器、手术设备和动物护理、组织学资源和用于体内记录的多通道采集系统。校内计划中的培训和职业发展资源，如每周实验室会议，由该领域领先的科学家进行的系列研讨会，职业发展研讨会以及负责任的研究行为培训，使NIAAA成为进行建议指导阶段的绝佳科学环境。 公共卫生相关性：在美国，酒精障碍是一个主要的健康问题，有1760万人（每12个成年人中有1人）滥用酒精或酒精依赖。目前的依赖理论表明，在依赖周期中习惯性药物和酒精寻求的增加可能是由连接皮质和纹状体脑区的回路功能障碍引起的。该项目旨在了解这些系统如何介导小鼠的行为，以便为调查酒精滥用和依赖的遗传和环境因素提供一个独特的模型。

DESCRIPTION (provided by applicant): Corticostriatal networks and NMDAR mediation of habitual and flexible action in the mouse. The objective of the proposed research is to investigate the neurocircuitry modulating the balance of habitual and flexible action that is thought to be dysfunctionally altered in alcohol dependence. Although studies in other species have provided strong evidence that these behaviors are mediated by networks connecting cortical and striatal subregions, this has not been well established in the mouse. In order for alcohol research to take full advantage of the molecular and genetic techniques that mouse models permit it is essential to first establish the role of these circuits in that species. I propose to elucidate the networks and molecular mechanism underlying habitual and flexible action in the mouse by using an integrative approach that combines traditional techniques (lesion and microinfusion) with emerging genetic and electrophysiological techniques. In order to do this, I propose three specific aims 1) Determine the involvement of corticostriatal networks and NMDAR mediation of well-learned and flexible behavior in the mouse. To accomplish this aim I propose to map endogenous activation patterns and examine the effects of subregion specific lesions in mice performing a task that requires both habitual and flexible action: visual discrimination and reversal. Further, the effects of NMDAR subunit loss in corticostriatal subregions on habitual and flexible performance will be tested using a conditional GluN2B mutant mouse model. 2. Examine in vivo electrophysiological activity of corticostriatal networks and the role of NMDAR during well- learned and flexible behavior. To accomplish this aim I propose to perform in vivo recording of neuronal activity in cortical and striatal subregions during performance of the discrimination-reversal task in both non-mutant mice and the GluN2B conditional mutant model. 3. Examine in vivo electrophysiological activity of corticostriatal networks during higher-order measures of executive control. In order to complete this aim I propose to perform electrophysiological recording in non-mutant and GluN2B mutant mice performing an operant task directly adapted from those used to measure executive control in clinical populations: visual set-shifting. Taken together, the completion of these specific aims will provide strong evidence for the role of corticostriatal networks and NMDAR in the mediation of flexible and habitual actions and provide a strong foundation for future studies investigating how these systems are dysregulated in alcohol abuse and dependence. During my graduate training and fellowship I developed the knowledge of scientific design and conduct necessary to complete the mentored training and development necessary to succeed in the proposed experiments. As a graduate student in the laboratory of Dr. Lawrence Rothblat I was trained in the fundamentals of design and conduct of neuroscience research using operant behavioral tasks with transgenic and mutant mouse models and gained experience in stereotaxic surgical procedures and histological techniques. During my fellowship at NIAAA under the mentorship of Dr. Andrew Holmes I have received extensive hands-on training in a broad range of behavioral measures and a variety of techniques for acute and chronic systemic drug administration as well as tissue micro-dissection for western blotting and high pressure liquid chromatography. In addition I have expanded his surgical techniques to include implantation of indwelling guide cannulae and micro-infusion of bioactive drugs in awake behaving animals. The mentored phase of the proposal will be conducted in the Division of Intramural Clinical and Biological Research at NIAAA under the mentorship of Dr. Andrew Holmes and the co-mentorship of Dr. David Lovinger. Dr. Holmes has extensive expertise in behavioral neuroscience techniques and a well-established research program using behavioral paradigms to investigate genetic and environmental factors underlying addiction and neuropathology using mouse models. Dr. Lovinger is a leader in studying the targets of alcohol and drugs of abuse using in vivo and ex vivo electrophysiology. This environment will provide all the necessary resources necessary to complete the research goals including, but not limited to behavioral apparatus, surgical equipment and animal care, histological resources and multi-channel acquisition systems for in vivo recording. The training and career development resources in the intramural program such as weekly laboratory meetings, seminar series conducted by leading scientists in the field, career development workshops, and training in the responsible conduct of research, make NIAAA an excellent scientific environment for conducting the mentored phase of the proposal. PUBLIC HEALTH RELEVANCE: Alcohol disorders represent a major health issue in the United States as 17.6 million people (H 1 in every 12 adults) abuse alcohol or are alcohol dependent. Current theories of dependence suggest that increases in habitual drug and alcohol seeking during the cycle of dependence may be caused by dysfunction in circuits connecting cortical and striatal brain areas. This project seeks to understand how these systems mediate behavior in the mouse, in order to provide a unique model for investigating the genetic and environmental factors underlying alcohol abuse and dependence.