Paul S. Katz - US grants

DESCRIPTION (provided by applicant): This grant is to request five years of support for the annual South East Nerve Net Conference. There are two basic goals of the meeting: to increase communication among neuroscience researchers in this corner of the country and to help in the training of students. This is the only regional general neuroscience conference in the Southeastern United States. It is an excellent means for neuroscientists in the South East to meet and form collaborations. The meeting has traditionally been very student-oriented, with the majority of talks being the first talks that students give at a major conference. We hope to preserve the friendly format for students while making this a large enough meeting to give them exposure to scientists outside of their own institutions. The venue for the meeting rotates between different locations in the South East each year. The meeting has previously been held at three locations in Florida: Whitney Laboratories in St. Augustine, Florida State University in Tallahassee, and University of Florida in Gainesville. In March of 2002, the meeting will be held in Atlanta GA, a site that is more central to the entire South East. It is hoped that this more central location will increase participation from Georgia, Tennessee, North Carolina, South Carolina, and Alabama to make it the first truly South East-wide Nerve Net Conference. We plan to have the meeting continue to rotate between the three Florida sites and Atlanta unless other universities in the South East express an interest in hosting the meeting. The 18th Annual meeting will be held March 1 and 2, 2002. The general format of the meeting will be: Friday evening there will be a talk by Dr. Thomas Insel of Emory University, followed by a reception. Then all day Saturday there will be 10 minute talks and posters, ending with a keynote address by Dr. George Augustine of Duke University and followed by a conference dinner.

DESCRIPTION (provided by applicant): Neuromodulation, the neurochemical alteration of neuronal and synaptic properties, is important for motor pattern generation and behavioral plasticity, yet few studies have explored the dynamics of neuromodulatory signaling in neuronal circuits. The goals of this project are to understand how intracellular signals mediating neuromodulatory actions are dynamically integrated over time and how this contributes to the production and plasticity of a motor behavior. The system being studied is the central pattern generator (CPG) underlying the rhythmic escape swimming response of the gastropod mollusc, Tritonia diomedea. This model system is uniquely suited to address these issues because it contains identified neurons, intrinsic to the CPG circuit, that use serotonin (5-HT) to evoke neuromodulatory actions in other CPG neurons. The proposed experiments test the hypotheses that the dynamics of 2nd messenger signaling evoked by this "intrinsic neuromodulation" play a direct role in motor pattern production and that summation of 2nd messenger signals contributes to termination of the behavior and to its habituation. Aim I is to visualize the temporal dynamics of Ca 2+ and cAMP during motor pattern production. Aim 2 is to identify which second messengers mediate particular neuromodulatory actions of 5-HT and serotonergic neurons. Aim 3 is to test the behavioral roles of dynamic biochemical signaling during motor pattern generation and plasticity. The experimental methods include electrophysiological and optical recordings in situ and in primary cell culture. Real-time changes in Ca 2+ and cAMP levels are measured using confocal and multiphoton imaging of fluorescent indicators. Second messengers are manipulated both pharmacologically and in real time with rapid photolysis of caged compounds. The objective is to directly observe and perturb dynamic biochemical signals during the production of the motor behavior. These experiments will elucidate general principles of how neuromodulatory signals are temporally integrated over behaviorally relevant time scales, thereby uniting the operation of neuronal networks with intracellular biochemical signaling networks. Understanding the dynamics of neuromodulatory mechanisms underlying signaling by biogenic amines in a motor system is likely to have significance for diseases related to defects in aminergic signaling such as Parkinson's disease and Huntington's disease.

Award Abstract
Different species of animals display disparate behaviors that are produced by underlying neural circuits in the brains of each animal. To understand how different behaviors may have evolved, it is necessary to compare how the neural circuits in closely related species differ. The objective of this project is to address three fundamental questions about the evolution of neural circuits underlying behavior: 1) How do similar nervous systems produce different behaviors? 2) Can the same neurons in different species have similar functions even though the behaviors of the animals differ? 3) How do nervous systems in animals of different lineages produce the same behavior?
This study addresses these questions by examining phylogenetic changes in identified homologous neurons in nudibranch mollusks, also known as sea slugs. Nudibranchs have simple nervous systems with individually identifiable neurons that underly three different types of locomotor behavior: crawling and two types of swimming: some sea slugs swim by lateral body flexions and others swim by dorsal/ventral body flexions. The divergent swimming behaviors arose independently multiple times in different nudibranch lineages. Studying phylogenetic differences in the functions and properties of identified neurons underlying locomotion will help determine how the behaviors changed during the evolutionary history of these sea slugs and will also provide understanding of how behaviorally relevant neural circuits can change in any creature.
Closely-related nudibranchs can exhibit divergent behaviors that are often associated with species-differences in the properties and connections of the underlying neurons. This project compares the neurophysiological properties and synaptic connections of homologous neurons that produce different behaviors in four closely-related species: Tritonia diomedea (a dorsal/ventral swimmer), Melibe leonina and Dendronotus iris (both lateral swimmers), and Tochuina tetraquetra (a non-swimmer). This part of the project will correlate neurophysiology with behavior to determine which features of the neurons or their circuit connections are functionally important. The functions of the neurophysiological properties then will be tested directly using an electrophysiological technique called dynamic clamp to artificially transform the membrane and synaptic properties of homologous neurons. If the properties of neurons can be electrically transformed so their activity more closely resembles that of the homologous neurons in other species and swim behavior typical of that species is produced, then it would be strong evidence that those neural properties play a causal role in the production of behavior.
Despite large differences in the behaviors of some closely-related nudibranchs, there likely will be underlying similarities in the functions of identified neurons. The second aim of the project is to look for conserved behavioral functions of homologous neurons in species with divergent behaviors. This will provide a basis for understanding the shared organization of the neural circuits, which forms the foundation upon which the derived behaviors are built.
Distantly-related nudibranchs can also display similar behaviors. The phylogenetic distribution of swim behaviors suggests that they arose independently multiple times. The third aim of this project is to test whether independent evolution of the same motor behavior was caused by convergent or parallel evolution. The functions of homologous neurons in nudibranchs of different lineages that exhibit the same swimming behavior will be tested. The species pairs to be examined are Aphelodoris antillensis and Tritonia diomedea, distantly related dorsal /ventral swimmers, and Flabellina iodinea and Melibe leonina, distantly related lateral swimmers. If homologous neurons came to be used in the same way, for the same purpose, independently in different lineages, then it would indicate that the similarity in the swimming behavior arose through parallel evolution. This would suggest that components of neural circuits are like building blocks that can be taken apart and reassembled in the same way. Alternatively, if it is found that the behaviors resemble each other because of convergent evolution, then it would indicate that there are multiple configurations of nervous systems that can produce the same behavioral output.
The project is designed to involve undergraduate students in the research plan. Specific mechanisms are in place to enhance the participation of historically under-represented ethnic groups. Plans have been made to use this project as a tool to teach about animal diversity and evolution in secondary schools using Georgia State University's Bio-Bus and to develop public exhibits on sea slugs at the new Georgia Aquarium in Atlanta.

[unreadable] DESCRIPTION (provided by applicant): Although nervous systems contain staggering numbers of neurons, it is possible to use electrophysiological, morphological, and molecular markers to classify neurons. Classification can become specific enough, especially in invertebrates, to identify individual neurons and map distinct neural circuits. Classifying neurons and mapping circuits is extremely valuable for neuroscience, as it elucidates the fundamental structure of the nervous system, providing a framework for understanding brain dysfunction. Unfortunately, progress is slow, as the work is tedious and there is no standard way to represent, store, and analyze the neuron types and wiring diagrams that emerge from these efforts. To help improve progress this project will develop NeuronBank, a public, on-line database of identified neurons and their synaptic connections that will serve as an important knowledge source and a novel informatics tool for the identification of new neuron types. Through collaboration between neuroscientists and computer scientists, a prototype NeuronBank will be developed that supports rich, flexible descriptions of identified neurons, allows features important to identification to be flagged, and provides source information and citable accession numbers. To facilitate further circuit mapping, NeuronBank will have facilities for comparing new observations to known cell types and suggesting diagnostics for determining if the cell is novel. NeuronBank will also feature an innovative 3-D visualization system to intuitively represent neuron location. The implementation will allow additional NeuronBank databases to be installed and modified easily by other researchers, enabling the evolution of a federation of databases uniting broad data sets. To road- test the prototype, NeuronBank will be stocked with large data sets from the molluscs Tritonia diomedea and Aplysia californica, both important model systems for motor pattern generation, learning, and memory. NeuronBank will then be used as an informatics tool to explore these systems for new neuron types. This proposal serves the purposes of PAR-03-036 (Innovative exploratory studies and technology development in Neuroinformatics Research) in several ways. It develops a new database and tools for neuroinformatics research. It is likely to have a high impact on future neuroscience research as it implements a unique neuroinformatics approach to neuron identification and neural circuit analysis. [unreadable] [unreadable]

This award will provide partial funding for a multi-day Friday Harbor Laboratory Centennial Symposium. The focus of the symposium is to summarize the important contributions that Gastropod mollucs have made to neuroscience research and to lay out ideas for future directions. Gastropods such as Tritonia, Aplysia, Helisoma, Helix, Lymnaea, Clione, Melibe, Hermissenda, and Pleurobranchaea have served as important model systems in neuroscience, in particular for studying motor pattern generation, learning, memory, development, ion channels and signal transduction. Leaders in this field are to be gathered together to create an opportunity to discuss in depth the directions Gastropod neuroscience should go in the future and plot courses to get it there.

More than twenty leaders in Gastropod neuroscience research have agreed to speak at this Friday Harbor Laboratory Centennial Symposium (http://depts.washington.edu/fhl/events.html). The intimate setting will provide an excellent opportunity to reflect on the current and future state of the field. The speakers will be asked to begin their talks by summarizing the important advances that have been made using their model systems and to end by discussing which direction they think the field should go and what will be needed to get it there. Round table discussions will be held that unite the themes of the talks and address the questions of "Where does the science go from here?" and "What tools are needed to get there?" A discussion will also be held on the use of new common tools such as the Aplysia Genome Project and NeuronBank.org. Posters will provide an outlet for young researchers to discuss their projects.

The meeting is seen as a way to promote cooperation in the field of Gastropod Neuroscience. Currently, there is no common venue for researchers in this field, yet there are many common issues that researchers face. The meeting will promote future research using Gastropod Molluscs by producing an accessible, innovative Wikipedia-style reference on Gastropod Neuroscience. It will also initiate a community web portal that will facilitate communication among researchers including job and meeting announcements.

[unreadable] DESCRIPTION (provided by applicant): Although nervous systems contain staggering numbers of neurons, it is possible to use electrophysiological, morphological, and molecular markers to classify neurons. Classification can become specific enough, especially in invertebrates, to identify individual neurons and map distinct neural circuits. Classifying neurons and mapping circuits is extremely valuable for neuroscience, as it elucidates the fundamental structure of the nervous system, providing a framework for understanding brain dysfunction. Unfortunately, progress is slow, as the work is tedious and there is no standard way to represent, store, and analyze the neuron types and wiring diagrams that emerge from these efforts. To help improve progress this project will develop NeuronBank, a public, on-line database of identified neurons and their synaptic connections that will serve as an important knowledge source and a novel informatics tool for the identification of new neuron types. Through collaboration between neuroscientists and computer scientists, a prototype NeuronBank will be developed that supports rich, flexible descriptions of identified neurons, allows features important to identification to be flagged, and provides source information and citable accession numbers. To facilitate further circuit mapping, NeuronBank will have facilities for comparing new observations to known cell types and suggesting diagnostics for determining if the cell is novel. NeuronBank will also feature an innovative 3-D visualization system to intuitively represent neuron location. The implementation will allow additional NeuronBank databases to be installed and modified easily by other researchers, enabling the evolution of a federation of databases uniting broad data sets. To road- test the prototype, NeuronBank will be stocked with large data sets from the molluscs Tritonia diomedea and Aplysia californica, both important model systems for motor pattern generation, learning, and memory. NeuronBank will then be used as an informatics tool to explore these systems for new neuron types. This proposal serves the purposes of PAR-03-036 (Innovative exploratory studies and technology development in Neuroinformatics Research) in several ways. It develops a new database and tools for neuroinformatics research. It is likely to have a high impact on future neuroscience research as it implements a unique neuroinformatics approach to neuron identification and neural circuit analysis. [unreadable] [unreadable]

This award supports the preparation and sharing of computational neuroscience data as part of a new component of the CRCNS program aimed at catalyzing rapid and innovative advances in computational neuroscience and related fields. Through a collaborative effort of many laboratories, this project combines knowledge about the nervous systems of several important gastropod model systems, including Aplysia, Clione, Helisoma, Helix (Cantareus), Hermissenda, Limax, Lymnaea, Melibe, Pleurobranchaea, and Tritonia, in an effort to lay the foundation for future comparative neuromics in gastropods.

Just as comparative genomics has enabled researchers to understand the evolution and development of organisms in terms of similarities and differences in their genomes, comparative neuromics, the comparison of neurons and their connections across species, offers unprecedented opportunities to increase our understanding of nervous system structure and function. Gastropod molluscs are uniquely suited for neuromic analysis because they have large individually identifiable neurons and work has proceeded for over four decades on species ranging from terrestrial and aquatic pulmonates to marine opisthobranchs, which inhabit diverse ecological niches. This project will consolidate the published knowledge about gastropod neurons and neural circuits into a searchable, extensible knowledge base, to be rendered in a format that can be federated with other knowledge repositories and primary data sources.

This project will build on currently available web-based tools and coordinate with other related efforts, such as NeuronBank, Open Biomedical Ontologies, and neuroscience-specific ontologies being developed for the Biomedical Informatics Research Network and the Neuroscience Information Framework. The gastropod user community is involved in providing sources of information and testing the outcome of the project to assure the accuracy of the representation and the usability of the format. Consolidating the vast amount of accumulated knowledge about gastropod nervous systems is essential for the expanded use of these model organisms as genomic tools become available through the Aplysia genome project and other initiatives. This project will serve as a basis for federating other databases including neuronal morphology, neuronal and neural circuit computational simulations, and signal transduction pathways. It will also serve as a proof of concept for larger research communities with more disparate nervous systems.

Understanding the neural mechanisms that cause species to behave differently has been an elusive goal in biology. This project, which is part of a doctoral dissertation, uses the nervous systems of sea slugs (opithobranch molluscs) to address this issue by comparing neural circuits underlying swimming behavior. Sea slugs have large neurons and simple nervous systems, allowing researchers to map out neural circuitry underlying equally simple behaviors. Some sea slug species swim by flexing their bodies up and down. Other species either do not swim or swim by other means. The neural circuitry underlying up and down swimming has been determined in two species: Tritonia diomedea and Pleurobranchaea californica. The neural circuits and interactions underlying swimming in these two species are remarkably similar even though these animals are not closely related. There is evidence to suggest the ability to swim evolved independently using the same (or homologous) neurons. This leads to the prediction that other species that swim in this manner would also use the same neurons and neural interactions to produce the behavior. To test this intriguing prediction, a third species of sea slug that swims with up and down movements will be be studied. The only readily available species are found in Australia. Electrophysiological, pharmacological, and histological approaches will be employed by the student to study the Australian species to determine if it also uses the same neurons and neural mechanisms. The results of this project will contribute to our understanding of the neural mechanisms that allowed behavior to evolve. A positive result would show that behavior could predict neural circuitry in animals that independently evolved the behavior. A negative result would still be interesting because it would show that similar behaviors can be produced by different mechanisms.

There are several broader impacts of this project. The first is that it will be a training opportunity for the student that will greatly enhance his dissertation project. The work will also establish a new partnership with colleagues internationally. The results of this project will be disseminated broadly both in the form of research papers, but also as contributions to NeuronBank.org, a project that tracks identified neurons and synaptic connections.

This project examines fundamental questions about the features of neural circuits that affect the evolution of behavior. The species being examined are nudibranch sea slugs, which have highly accessible nervous systems that allow experiments to be conducted that are not feasible in other types of animals. The brains of nudibranchs contain only about 10,000 nerve cells (neurons), many of which can be individually identified from animal to animal within a species. Furthermore, neurons can often be identified across different species. Electrical activity can be recorded from multiple neurons to reveal neural circuitry. The connectivity of those circuits can be compared across species. This research team found that although the species have the same sets of neurons, they are wired up differently, even when the species produce similar behaviors. One goal of the project is to artificially rewire the neurons in one species to produce the neural circuit of another species and to create mathematical models that do the same. This will establish how easy it is to convert the behavior of one species into that of another. It also contributes to understanding the basic rules for generating behavior by comparing across species instead of focusing on a single species. The project engages the public by soliciting observations of nudibranch behavior from divers around the world through social media. It also provides important research opportunities to under-represented students through a research pipeline and creates resources that will be available to the scientific community to aid in identifying neurons and mapping out circuits.

Evolvability reflects the ability to evolve. This project examines the features of neural circuits that affect the evolvability of swimming behaviors in nudibranchs. The project uses a variety of techniques to achieve its goals. First, transcriptomics is used to resolve the phylogeny of the Nudibranchia and allow phylogenic hypotheses to be tested. The brain transcriptomes further aid in the discovery of molecular markers for identified neurons, which are needed particularly in species that do not swim. Electrophysiological techniques are used to search for "latent" circuitry, that is, connectivity that might be present in non-swimmers and potentially activated by small changes. These changes will be applied using the dynamic clamp technique to inject artificial synaptic and membrane conductances and through ectopic expression of serotonin receptors. Finally, mathematical simulations are used to examine the consequences of different circuit architectures and their robustness for rhythmic activity.

Project Summary / Abstract This project is a collaboration between researchers at four universities to examine how the brain makes decisions. When a human or any animal moves through the world, it must make constant decisions about what to do next. These decisions are based on the state of the animal, its past history, and its future goals. In most animals, it is difficult or impossible to examine the neural mechanisms underlying the translation of a decision into an actual motor act because of the complexity of the neural computation, the number of neurons involved, and the complexity of the physical change produced by the movement of the animal. To reduce all three of these complexities, this project examines foraging decisions made by the brain of a nudibranch mollusc, Berghia stephanieae. This sea slug has fewer than 7000 neurons and they are identifiable as individuals or as members of particular classes. This project will map out all of the synaptic connectivity of the brain (the connectome) by serially sectioning the brain and reconstructing neurons and synapses from electron microscopic images. The RNA expressed by each of the neurons in the brain will sequenced and their transcriptomes mapped onto each neuron in the connectome. This will allow neuromodulatory connectivity to be inferred and overlaid on the synaptic connectivity, producing a ?neuromodulome?. The project will develop CRISPR/cas9 gene editing techniques for this ?non-model? organism, allowing genetically-encoded sensors and activators to be expressed in neuron classes. The decision-making process will be observed in a closed-loop semi-intact preparation where the brain of the animal controls a virtual environment that the brain navigates through using its own neural commands. Multiple neurons at a time will be recorded from using voltage-sensitive dyes or genetically-encoded sensors. This real-time neural spike activity will be mapped onto the connectome, allowing the dynamics of the circuitry to be observed. Mathematical and statistical methods will be used to analyze these dynamic networks. The result will be the algorithm and its implementation in the brain of the sea slug. The project will then examine how this circuit changes as the brain and the body grow and add neurons. Understanding how neural circuits add neurons while continuing to function is an important basic research question that links directly to human disease because adult neurogenesis in humans has been linked to many cognitive and mood disorders.

PROJECT 2 SUMMARY/ABSTRACT ? Project 2. Behavioral Analysis and Recording This project examines the behavior of nudibranch mollusc Berghia as part of the larger Berghia Brain Project. Careful behavioral analysis is crucial for an understanding of the neural basis of behavior. This project uses innovative approaches to understand how this animal changes its behavior in response to tactile, chemosensory, and visual stimuli. The project uses innovative technology including machine learning to automatically classify behavior, a tracking system that allows the animal to explore an arena while remaining stationary with respect to a microscope objective, and optogenetic stimulation. The questions being addressed are related to the global problems of how a brain interacts with a complex network to produce behavior. In particular, the Project addresses how multimodal sensory information affects behavioral responses.

PROJECT SUMMARY/ABSTRACT ? Administrative Core The Administrative Core of the Berghia Brain Project will support multi-disciplinary research, aid in the dissemination of research findings, and foster team-building, synergy, and integrative capacity among participants. The Administrative Core will also evaluate all Projects and Cores, to ensure success of the Berghia Brain Project. It will create and manage a process to coordinate research activities using innovative internal communication channels. The Administrative Core will develop and implement financial and human resources policies and procedures and evaluate all Berghia Brain Project activities.

SUMMARY / ABSTRACT ? Project 1. Multi-feature, Multi-scale Atlas Project 1 of the Berghia Brain Project is to create a multi-scale, multi-feature atlas of the Berghia brain and peripheral neural plexus. Berghia has a brain that is both physically small enough to be serially sectioned and reconstructed from electron micrographs and also has few enough neurons that they can be individually characterized and catalogued. Developing the tools for this undertaking will aid in the long term goal of the BRAIN Initiative to fully map the human brain. The Berghia brain atlas will contain the connectivity, neuroanatomy, and gene expression profile of individual neurons in the brain. It will also feature how those central neurons connect to neurons in periphery and to end organs. The peripheral plexus itself will be characterized and mapped. This will aid in understanding how a brain and a distributed periphery interact. The atlas will be used to trace out the somatosensory, olfactory, and visual systems to test fundamental models of how these systems are organized. This project will determine whether somatotopic maps are present in the brain. It will also determine how an olfactory system is organized without glomeruli. Finally, it will examine the distributed, multi-sensory nature of vision.