DESCRIPTION (provided by applicant): The Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative has the ambitious goal of elucidating how neuronal ensembles interactively encode higher brain processes.
DESCRIPTION (provided by applicant): Driver lines that direct Cre protein to specific neuron types have proven to be invaluable tools to not only visualize specific neuron types but also to manipulate their activity through the Cre- mediated activation of optogenetic probes or to assess gene function by Cre-mediated gene knockout. Most Cre driver lines, such as BAC-based Cre drivers or knock-ins of Cre into specific loci, monitor the complete expression pattern of entire genetic loci.
DESCRIPTION (provided by applicant): A fundamental goal of neuroscience is to understand the function(s) of defined neural populations in a complex organism. We propose to develop and validate a technology for non- invasive modulation of neural activity in vivo. There has been huge progress in developing tools for temporal regulation of neural activity. These techniques, from light activated channels to designer receptors, enable modulation of defined neural populations in vivo to examine their roles in many physiological functions. But current technologies have their limitations.
DESCRIPTION (provided by applicant): Molecular definitions of neural cell types largely depend on the expression of RNAs or proteins as assessed by in situ hybridization, RNA array and sequencing, and immunohistochemistry. However, recent studies are demonstrating that gene regulatory elements, such as enhancers, can have highly specific spatial and temporal activity patterns in the developing brain. Thus, enhancer activity can be used to define neural cell types, and importantly, also have other broad applications.
DESCRIPTION (provided by applicant): Significant work is ongoing to reveal how different cell types in the brain contribute to behavior and pathology, and how they change in plasticity and disease, empowered by new genetic, optical, and physiological tools. However, the functional activity and dysregulation of neuronal circuits relies critically on the in situ molecular composition of neuronal synapses.
DESCRIPTION (provided by applicant): Neurons communicate information through fluctuations in the electrical potentials across their cellular membranes. Whole-cell patch clamping, the gold standard technique for measuring these fluctuations, is something of an art form, requiring great skill to perform on only a few cells per day. Thus, it has been primarily limited to in vitro experiments, a few in vivo experiments, and very limited applications in the awake brain. Dr. Forest (and collaborator Dr.
DESCRIPTION (provided by applicant): Genetic tools have dramatically increased the power and resolution of neuroscientific experiments, allowing monitoring and perturbation of specific neuronal populations within the brain, often in the context of complex cognitive and behavioral paradigms. However, the usefulness of these tools is limited by the available means of delivering them in circuit-specific ways, a major drawback in view of the critical importance of specific connectivity between individual neurons and between neuronal classes.
DESCRIPTION (provided by applicant): Our understanding of brain function at the cellular and circuit level is critically dependent on the ability to interrogate and alter neural cells withhigh specificity. The use of light, either through single-photon or multi- photon excitation, is the onl method that provides sufficient resolution to probe the brain at the cellular and subcellular levels.
DESCRIPTION (provided by applicant): Dramatic new insights into the functioning of neural networks have been made possible by our ability to visualize neural function with calcium-sensitive fluorophores, and biology has been revolutionized by the ability to sequence and manipulate DNA, RNA, and proteins. Both of these tremendous advances have unexplored "flip sides". Our understanding of neural network function remains limited by our inability see GABA-mediated synaptic activity: we can't measure the output of the remarkable diversity of interneuron structure and function.
DESCRIPTION (provided by applicant): Cajal revolutionized the study of the brain through the use of the Golgi stain to label cells sparsely and stochastically in a fashion that revealed a neuron's morphology in its entirety. Although genetic tools for sparse and stochastic labeling and manipulation of single neurons in Drosophila have been used extensively over the past 15 years, they have only recently become available for mammalian systems, but the latter tools are limited to only a few systems for which cell-type specific reagents (e.g.
