Joshua H. Singer, PhD - US grants
Affiliations: | Biology | University of Maryland, College Park, College Park, MD |
Area:
Retina, Amacrine CellsWebsite:
http://biology.umd.edu/joshua-singer.htmlWe are testing a new system for linking grants to scientists.
The funding information displayed below comes from the NIH Research Portfolio Online Reporting Tools and the NSF Award Database.The grant data on this page is limited to grants awarded in the United States and is thus partial. It can nonetheless be used to understand how funding patterns influence mentorship networks and vice-versa, which has deep implications on how research is done.
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High-probability grants
According to our matching algorithm, Joshua H. Singer is the likely recipient of the following grants.Years | Recipients | Code | Title / Keywords | Matching score |
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2005 — 2007 | Singer, Joshua H | K22Activity Code Description: To provide support to outstanding newly trained basic or clinical investigators to develop their independent research skills through a two phase program; an initial period involving and intramural appointment at the NIH and a final period of support at an extramural institution. The award is intended to facilitate the establishment of a record of independent research by the investigator in order to sustain or promote a successful research career. |
Synaptic Transmission in the Mammalian Inner Retina @ Northwestern University DESCRIPTION (provided by the applicant): The following is a research and training plan that I will conduct first in the laboratory of Dr. Jeffrey Diamond in the Synaptic Physiology Unit of the National Institute of Neurological Disorders and Stroke (NINDS) at the Bethesda campus of the National Institutes of Health and later in my own laboratory. My primary research interest is the physiology of synaptic transmission: specifically, the pre- and postsynaptic factors that determine the time course of information transfer between two neurons in the central nervous system (CNS). My long-term career goal is to be a principal investigator at a research university, overseeing a laboratory that uses electrophysiological and fluorescence imaging techniques to answer questions about the fundamental properties of synapses. The short term objective of my training with Dr. Diamond is to learn to develop quantitative descriptions and models of excitatory synaptic transmission in the mammalian retina, focusing on dyad synapses made by rod bipolar cells onto two types of amacrine cell: the AII and the A17. This component of the mammalian rod pathway will serve as the experimental model around which inquiry, in my own laboratory is structured initially. The proposed research project will encompass three specific aims: 1) To determine the factors that govern the timing of glutamate release from the rod bipolar cell, 2) to understand how the postsynaptic properties of the amacrine cells shape the time course and strength of post-synaptic responses, 3) to investigate how signals that originate in the AII amacrine cell are altered when propagated through gap junctions to other AII amacrine and cone bipolar cells. |
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2007 — 2021 | Singer, Joshua H | R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Synaptic Transmission in the Rod Pathway of the Mammalian Retina @ Univ of Maryland, College Park Project Summary: The broad goal of our research program is to understand how neural circuit function depends on the intrinsic properties of component cells and synapses. The specific goal of this proposal is to determine how synaptic inhibition in inner-retinal circuits shapes responses observed in retinal ganglion cells (GCs), the retinal output channels. This proposal is focused on inhibition in a well-studied inner-retinal circuit: the rod bipolar (RB) cell pathway of the mouse retina, which comprises two central neurons, the ON RB and the AII amacrine cell (AC). The AII distributes the RB signal to several retinal output channels, most significantly the ON ? and OFF ? and ? GCs, and in the past project period, we identified two novel ACs (nNOS-1 and Rpb4) that provide synaptic inhibition to the RB-AII network. Both of these ACs receive input from the type 6 ON cone bipolar (CB) cell, and the properties of the type 6 CB are thought to generate the contrast-sensitivity and well-characterized nonlinear receptive field of the ON ? GC. Therefore, we advance the hypothesis that local contrast in the visual scene best engages these novel inhibitory circuits and that the response properties of nNOS-1 and Rpb4 ACs should be evident in the responses of AIIs and downstream ON ? and OFF ? GCs. Our goal is to elucidate cellular properties and responses to physiological stimuli at various stages in the RB pathway to understand the functions of these novel inner retinal circuits. The two specific aims proposed will generate an understanding of how variations in the visual scene modulate signal coding within individual retinal output channels: Aim 1 tests the hypothesis that nNOS-1 ACs exhibit a non-classical receptive field surround that is manifested in the responses of downstream neurons in the retinal circuit; Aim 2 expands our combined anatomical and physiological analyses to resolve how distinct inhibitory circuits converge on GCs and permit coding of unique components of the visual scene. Relevance to Public Health: Understanding how visual stimulus coding is implemented by retinal synapses informs the design of retinal prosthetics and the study of animal models of human retinal diseases. The proposed work clarifies how visual signal processing is modulated at three stages in the retinal network and addresses two goals of the Retinal Diseases Program in the National Plan for Eye and Vision Research: one, it builds on knowledge gained from retinal neuroscience to understand how retinal networks process visual images, and two, it works toward identifying the post photoreceptor neural components of adaptation. |
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2010 — 2012 | Singer, Joshua H | R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Crcns: Biophysical Properties of Parallel Neural Circuits Serving Night Vision @ Northwestern University At Chicago DESCRIPTION (provided by applicant): This project is a collaboration between two neurobiologists and two applied mathematicians. Its main goal is to combine experiment and computation to develop a detailed understanding of how the biophysical properties of individual retinal neurons and synapses shape the parallel processing of visual information during rod vision. We will characterize experimentally and model computationally the components composing the neural circuitry of the mammalian retina that subserves night (scotopic) vision. The anatomy of this circuitry is well-described: photons absorbed by rod photoreceptors generate neural signals that are distributed to multiple types of retinal ganglion cells (GCs), the output cells of the retina, via a series of interneurons. These interneurons are coupled to each other by both chemical and electrical synapses. Each type of GC has a unique response to light, which is presumed to reflect the properties of the circuitry presynaptic to it. This allows each GC type to encode a different feature of the visual scene, thereby facilitating further abstractions by the higher brain areas that ultimately guide behavior. By characterizing and carefully modeling each component, by assembling the components into a comprehensive model, and by validating and refining the overall model experimentally, we will determine how diverse GC outputs emerge from the biophysical properties of parallel retinal microcircuits. Intellectual merit: The retina is one of the few neural circuits for which output evoked by physiological stimuli is similar in vitro and in vivo, making it amenable to experimental analysis. The sheer volume of information encoded by the retina, however, makes understanding its functional circuitry difficult. In an iterative process of simulation and experiment, we will develop detailed biophysical models of the retinal network utilized for rod vision. In particular: 1) Data to constrain ion channel models will be acquired by direct recording from neurons of interest;2) Chemical and electrical synapses will be characterized directly by recording from pairs of synaptically coupled neurons;data will be used to construct a network model of the rod pathway;3) Compartmental models of different neurons will be constructed using anatomical and physiological parameters determined by experiment;4) The overall network model will be validated and refined using light-evoked recordings from different classes of GCs. The computational model will provide a framework in which experiments probing parallel processing of rod signals within the retinal network may be understood. Moreover, we will explore the parameter space within which the model network operates to develop new and experimentally testable hypotheses about retinal function. Broader Impacts: Validated computational models will be made available via the ModelDB database, a public repository of neuronal models, thereby providing a tool to allow other researchers to develop new experimentally testable hypotheses about retinal processing. More generally, the data obtained through this project and the accompanying computational model will provide a validated example of information processing in neural circuits;such information can serve as an example of possible information processing in other neural systems. The proposed project also will provide neuroscientists and applied mathematicians the opportunity for detailed cross-disciplinary training. Applied mathematics students will acquire a solid background in neuroscience, and neuroscience students will acquire a foundation in quantitative modeling techniques. Teaching materials developed as part of this interaction will be made available to the larger neuroscience community. Additionally, the PIs will pursue opportunities to organize a meeting or symposium (e.g., at the annual Society for Neuroscience meeting) to bring together researchers working on combined experimental and computational studies of neural circuits. |
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2014 — 2016 | Demb, Jonathan B Singer, Joshua H |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Computation At Retinal Synapses @ Univ of Maryland, College Park DESCRIPTION (provided by applicant): Our long-term goal is to understand how retinal circuits perform the computations underlying healthy vision. The immediate goal of this proposal is to understand how retinal circuits adjust their properties to the contrast of a visual scene. Contrast adaptation is important for visual processing across eye fixations and between different environments: it increases sensitivity at low contrast to improve the signal-to-noise ratio, and it decreases sensitivity at high contrast to prevent response saturation. Presently, we know relatively little about the cellular and synaptic basis for contrast adaptation in the mammalian retina. This proposal comprises two specific aims that will generate novel insights into the synaptic mechanisms underlying contrast adaptation by integrating synapse- and circuit-level analyses of retinal signaling. In one approach, responses to contrast stimulation of photoreceptors will be recorded in specific types of retinal interneurons identified by genetic expression of fluorescent proteins and visualized by two-photon laser-scanning microscopy. In a second approach, we will use optogenetic control of subtypes of interneurons to examine transmission at specific synapses. Using these complementary approaches, Specific Aim 1 will determine the mechanisms for contrast adaptation in dim light by probing a specialized pathway for rod vision. Specific Aim 2 will determine the mechanisms for contrast adaptation at brighter light levels by probing parallel pathways for cone vision. Relevance to Public Health: Understanding how contrast adaptation is implemented by retinal synapses and circuits generates fundamental information about the neural basis of vision and informs the design of retinal prosthetics and the study of animal models of human retinal diseases. A goal of vision research is the development of gene-based therapies for treating blindness caused by photoreceptor degeneration (e.g., retinitis pigmentosa). A promising therapy of this sort is the generation of light sensitivity in retinal interneurons using virally-mediated expression of channelrhodopsin-2 (ChR2), a light-gated cation channel. We will express ChR2 in interneurons to study synaptic interactions in retinal circuits; by design, we will compare photoreceptor- and ChR2-mediated circuit outputs. Thus, we will generate critical information about the range of visual signals that could be encoded by a retina in which ChR2 is the only light sensor. We address three goals of the Retinal Diseases Program in the National Plan for Eye and Vision Research: 1) determining potential therapeutic strategies for treatment of retinitis pigmentosa, 2) increasing understanding of post-photoreceptor adaptation (i.e., gain control in neural circuits), and 3) increasing understanding of how inter-cellular interactions in neural networks generate signals that are interpretable as visual images. |
0.987 |