Corticostriatal networks and NMDAR mediation of habitual and flexible action

描述（由申请人提供）：皮质纹状体网络和NMDAR介导小鼠的习惯性和柔韧性动作。本研究的目的是研究被认为在酒精依赖中功能失调的调节习惯性和灵活行为平衡的神经回路。尽管对其他物种的研究提供了强有力的证据，表明这些行为是由连接皮层和纹状体亚区的网络介导的，但这在小鼠身上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，首先必须确定这些回路在该物种中的作用。我建议通过将传统技术（损伤和微输液）与新兴的遗传和电生理技术相结合的综合方法来阐明小鼠习惯性和灵活动作的网络和分子机制。为了做到这一点，我提出了三个具体目标：1)确定皮质纹状体网络和NMDAR介导小鼠良好学习和灵活行为的参与。为了实现这一目标，我建议绘制内源性激活模式，并检查亚区域特异性病变对小鼠执行一项需要习惯性和灵活动作的任务的影响：视觉辨别和逆转。此外，将使用条件GluN2B突变小鼠模型测试皮质纹状体亚区NMDAR亚基丢失对习惯和灵活表现的影响。2. 检查皮质纹状体网络的体内电生理活动和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条件突变模型中，在执行区分逆转任务时，对皮质和纹状体亚区进行神经元活动的体内记录。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，这些小鼠执行一项直接改编自用于测量临床人群执行控制的操作任务：视觉集转移。总之，这些具体目标的完成将为皮质纹状体网络和NMDAR在灵活和习惯性行为的调解中的作用提供强有力的证据，并为未来研究这些系统如何在酒精滥用和依赖中失调提供坚实的基础。在我的研究生培训和奖学金期间，我发展了科学设计和行为的知识，这是完成指导培训和发展所必需的，这是成功完成拟议实验所必需的。作为Lawrence Rothblat博士实验室的研究生，我接受了设计和实施神经科学研究的基础训练，使用转基因和突变小鼠模型的操作性行为任务，并获得了立体定向外科手术和组织学技术方面的经验。在NIAAA实习期间，在Andrew Holmes博士的指导下，我接受了广泛的行为测量和各种急性和慢性全身药物管理技术的实践培训，以及组织显微解剖的western blotting和高压液相色谱。此外，我还扩展了他的外科技术，包括在清醒行为的动物中植入留置引导管和微输生物活性药物。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博士指导，David 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，并建立了一个完善的研究项目，使用行为范式调查成瘾和神经病理学背后的遗传和环境因素。Lovinger博士是使用体内和体外电生理学研究酒精和药物滥用目标的领导者。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。校内项目中的培训和职业发展资源，如每周实验室会议、由该领域的顶尖科学家主持的系列研讨会、职业发展讲习班和负责任的研究行为培训，使NIAAA成为开展提案指导阶段的良好科学环境。

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.