Divya Sitaraman - US grants

Sleep and arousal regulate key behavioral and physiological processes. Inadequate sleep or impaired sleep-wake transitions lead to a range of cognitive, attentional, motor, and emotional deficits. Treatment and management of these conditions will benefit greatly from an understanding of how sleep-wake transitions are controlled and how the homeostatic sleep drive is encoded in the nervous system. A long term goal of this proposal is to understand the precise circuit mechanisms underlying the neural control of sleep, and how this circuit is regulated by behavioral drive. The goal of this proposal is to exploit Drosophila as an experimental system in which we can mechanistically dissect the neuronal underpinnings of the sleep control network and identify mechanisms by which conserved neuromodulators like dopamine regulate sleep. Technical challenges that have limited prior findings in this area are lack of cell type specific tools and inability to physiologically map circuits with accuracy. To surmount these challenges, we will combine the unique cell-specific neurogenetic manipulability of the Drosophila model system with an array of behavioral and novel neurophysiological approaches. In pursuit of identifying and characterizing dopamine regulation of sleep control network in Drosophila we have proposed three specific aims. In Aim 1, we will identify the functional connectivity between dopamine neurons and key sleep- and wake- promoting neurons within the associative neural network of mushroom body. By reciprocal activation and blocking of functionally upstream and downstream neurons we will map how the sleep and arousal information flow occurs within the identified sleep regulating neurons. In Aim 2, we will employ direct physiological mapping tools to identify functional connectivity within sleep regulating neurons by stimulating one neural node while recording from the other using genetically encoded calcium and voltage indicators. Finally, in Aim 3 we will test if activity of the sleep-regulating dopamine neurons is influenced by altered sleep-drive. Additionally, we will characterize the nature of synaptic inputs to the dopamine neurons using techniques refined and validated in Aims 1 and 2. The combination of novel genetic, behavioral and physiological approaches and successful completion of these Aims will address questions of great relevance to mammalian sleep circuit that have been plagued by technical challenges. These include the role of dopamine in modulating activity of sleep regulating neurons, synaptic plasticity mechanisms underlying the sleep-wake switch, and the cellular encoding of sleep drive.

While it is understood that students experience tremendous educational benefits from exposure to authentic research as part of their undergraduate coursework, the availability of these experiences may be limited by high cost and difficult implementation. The Connectomes for Undergraduate Neuroscience Education and Learning (CUNEL) project seeks to provide students with access to cutting-edge neuroscience research tools and provide the framework to integrate these tools into their undergraduate education. The CUNEL project will accomplish this by recruiting and training a network of neuroscience instructors who will implement and assess laboratory protocols that provide authentic research experiences in connectomics, the burgeoning field of neuroscience that seeks to create comprehensive maps of synaptic connectivity, the ‘wiring diagram’ showing how nerves connect within a nervous system. The broad outcome of the CUNEL project will be to enhance both the quality and accessibility of neuroscience education, while providing undergraduate students with real-world scientific experience within an area of neuroscience at the forefront of the field. <br/><br/>The CUNEL project will create, implement, and assess undergraduate laboratory materials that make use of the publicly available Female Adult Fly Brain (FAFB) dataset and Collaborative Annotation Toolkit for Massive Amounts of Image Data (CATMAID) software platform. The CUNEL team will create instructional materials that facilitate adoption, implementation, and assessment of FAFB/CATMAID laboratory modules in undergraduate classes at diverse undergraduate institutions. These modules will be disseminated and assessed through a user network of neuroscience instructors who will be recruited, supported, and coordinated by the project leadership. Students who work with laboratory materials created by the CUNEL project will have opportunities to engage scientifically with students at other network institutions and with the connectomics research community. The outcomes of this project will include: 1) the creation of laboratory materials that can be successfully implemented at a wide variety of undergraduate institutions to provide authentic research experiences in connectomics as part of undergraduate coursework, and 2) the creation and organization of a network of neuroscience educators who will collaborate to enhance neuroscience education using these authentic research tools.<br/><br/>This project is being jointly funded by the Directorate for Biological Sciences, Division of Biological Infrastructure, and the Directorate for Education and Human Resources, Division of Undergraduate Education as part of their efforts to address the challenges posed in Vision and Change in Undergraduate Biology Education: A Call to Action (http://visionandchange/finalreport/).<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.