A5057642391- Retinal Development and Disorders
- Photoreceptor and optogenetics research
- Neural dynamics and brain function
- Neuroscience and Neuropharmacology Research
- Neuroscience and Neural Engineering
- Visual perception and processing mechanisms
- Photonic and Optical Devices
- Circadian rhythm and melatonin
- Glaucoma and retinal disorders
- Neurobiology and Insect Physiology Research
- Olfactory and Sensory Function Studies
- Semiconductor Lasers and Optical Devices
- Optical Imaging and Spectroscopy Techniques
- Photonic Crystals and Applications
- Retinal and Macular Surgery
- Zebrafish Biomedical Research Applications
- Adenosine and Purinergic Signaling
- Infrared Thermography in Medicine
- Geophysics and Sensor Technology
- bioluminescence and chemiluminescence research
- Migraine and Headache Studies
- Mitochondrial Function and Pathology
- Intraocular Surgery and Lenses
- Advanced Chemical Sensor Technologies
- Magneto-Optical Properties and Applications
University of St. Francis
2024
University of California, San Francisco
2014-2023
City College of San Francisco
2019
University of Washington
2003-2014
Eunice Kennedy Shriver National Institute of Child Health and Human Development
2012
National Institutes of Health
2012
University of Hyderabad
2012
Brown University
2002-2007
Light synchronizes mammalian circadian rhythms with environmental time by modulating retinal input to the pacemaker—the suprachiasmatic nucleus (SCN) of hypothalamus. Such photic entrainment requires neither rods nor cones, only known photoreceptors. Here, we show that ganglion cells innervating SCN are intrinsically photosensitive. Unlike other cells, they depolarized in response light even when all synaptic from and cones was blocked. The sensitivity, spectral tuning, slow kinetics this...
The intrinsically photosensitive retinal ganglion cells (ipRGCs) provide a conduit through which rods and cones can access brain circuits mediating circadian entrainment, pupillary constriction other non-image-forming visual functions. We characterized synaptic inputs to ipRGCs in rats using whole-cell multielectrode array recording techniques. In constant darkness all received spontaneous excitatory inhibitory inputs. Light stimulation evoked both synaptically driven ('extrinsic')...
Effective sensory processing requires matching the gain of neural responses to range signals encountered. For rod vision, controls operate at light levels which photons arrive rarely individual rods, too low cause adaptation in phototransduction. Under these conditions, within a conserved pathway mammalian retina maintains sensitivity as change. To relate retinal behavioral work on detection levels, we measured how background affects and noise primate ganglion cells. determine where is...
An apparatus for the measurement of attenuation light in thin-film waveguides is described. It involves a prism that rides on liquid film along guide and couples out guide. A spatial resolution ~0.5 mm an accuracy 0.02 dB/cm were achieved.
Sensory circuits use common strategies, such as convergence and divergence, typically at different synapses, to pool or distribute inputs. Inputs from presynaptic cell types converge onto a postsynaptic cell, acting together shape neuronal output (Klausberger Somogyi, 2008). Also, individual cells contact several types, generating divergence of signals. Attaining complex wiring patterns relies on the orchestration many events across development, including axonal dendritic growth synapse...
Loss of primary neuronal inputs inevitably strikes every neural circuit. The deafferented circuit could propagate, amplify, or mitigate input loss, thus affecting the circuit's output. How contributes to effect on output is poorly understood because lack control over loss and access elements. Here, we timing degree rod photoreceptor ablation in mature mouse retina uncover compensation. Following half rods, bipolar cells by preserving voltage Such mitigation allows partial recovery ganglion...
Sensory processing can be tuned by a neuron's integration area, the types of inputs, and proportion number connections with those inputs. Integration areas often vary topographically to sample space differentially across regions. Here, we highlight two visual circuits in which topographic changes postsynaptic retinal ganglion cell (RGC) dendritic territories their presynaptic bipolar (BC) axonal are either matched or unmatched. Despite this difference, both circuits, inputs from each BC...
Highlights•Type 6 bipolar cell dendrites remodel following cone death in mature retina•Bipolar input synapses are dependent, while output invariant•Cone loss leads to narrower excitation and wider inhibition of AON-S ganglion cells•Spatial receptive field changes not recapitulated by partial stimulationSummaryResilience neural circuits has been observed the persistence function despite neuronal loss. In vision, acuity sensitivity can be retained after 50% cones. While neurons cortex loss,...
Following input loss from degeneration, injury, and/or aging, downstream circuits undergo modifications that can impact fundamental sensory computations. Using the retina to leverage known cell types, well-defined circuitry, and molecular tools, we show how multiple pathways adjust their functional properties differently common further locate these changes within each pathway. Specifically, asked if two OFF ganglion alpha OFF-sustained (A OFF-S ) OFF-transient OFF-T cells, respective...
Noisy or spontaneous activity is common in neural systems and poses a challenge to detecting discriminating signals. Here we use the locust answer fundamental questions about noise olfactory system: Where does originate? How this propagated reduced throughout multiple stages of processing? What mechanisms favor detection signals despite presence activity? We found that long observed secondary projection neurons (PNs) originates almost entirely from primary receptor (ORNs) rather than circuit...
Structural changes underlying neurodegenerative diseases include dismantling of synapses, degradation circuitry, and even massive rewiring. Our limited understanding synapse stems from the inability to control timing extent cell death. In this study, selective ablation cone photoreceptors in live mouse retina tracking postsynaptic partners at cone-to-ON bipolar reveals that early reaction loss involves rapid local glutamate receptor distribution. Glutamate receptors disappear with a time...
Across species, the optokinetic reflex (OKR) stabilizes vision during self-motion. OKR occurs when ON direction-selective retinal ganglion cells (oDSGCs) detect slow, global image motion on retina. How oDSGC activity is integrated centrally to generate behavior remains unknown. Here, we discover mechanisms that contribute encoding in vertically tuned oDSGCs and leverage these findings empirically define signal transformation between output vertical behavior. We demonstrate contrast-sensitive...
Specificity and timing of synapse disassembly in the CNS are essential to learning how individual circuits react neurodegeneration postsynaptic neuron. In sensory systems such as mammalian retina, synaptic connections second-order neurons known remodel reconnect face cell loss. Here we analyzed whether degenerating third-order can their local presynaptic connectivity. We injured adult retinal ganglion cells by transiently elevating intraocular pressure. show that loss structures occurs...
Retinal responses to photons originate in rod photoreceptors and are transmitted the ganglion cell output of retina through primary bipolar pathway. At first synapse this pathway, input from multiple rods is pooled into individual cells. This architecture called convergence. Convergence serves improve sensitivity vision when sparse. Establishment convergence depends on development a proper complement dendritic tips transduction proteins How dendrites cells develop contact appropriate number...
The rectangular waveguide resonance isolator operating at frequencies from 3000 to 24,000 mc is a simple and compact device since the dc magnetic field requirements are relatively low. In 5-mm range, however, isolators not practical if conventional ferrites used because very high fields of about 20,000 oersteds required obtain these frequencies. By using highly oriented Ferroxdure, in millimeter range become feasible internal anisotropy 17,000 exhibited by this material. Thus, with...