Clare Chung
University of California, San Francisco
Characterization of Zebrafish mutants
I am postdoctoral fellow in Dr. Juan Korenbrot's laboratory. My project is studying the electrophysiology and anatomy of developing retinal ganglion cells in juvenile trout and investigating how the network of these cells is established during development.
For the Grass fellowship, I am characterizing zebrafish motion detection mutants by examining their electroretinograms, spike trains and anatomy of retina.
Karen J. Cusato
Albert Einstein College of Medicine
Gap Junction-Mediated Cell Death
I am a postdoc in David Spray's lab, where I study the role of gap junctions in cell death in developing retina. An important question is which connexins (gap junction proteins) allow bystander cell killing. Connexins display differential sensitivity to gating stimuli; it is possible that only some connexins remain open during cell death. At the MBL this summer, we have measured the gap-junctional conductance between pairs of oocytes by voltage clamp, following induction of cell death in one oocyte. Cx38 channels remain open during cell death and we intend to screen other connexins normally expressed in the retina.
Ian G. Davison
Simon Fraser University
Lateral inhibition of sensory inputs to the olfactory bulb
I have just completed my Ph.D., studying synaptic modulation and dendritic excitability in the olfactory bulb with Kerry Delaney. My Grass project examines whether inhibitory neurons (periglomerular cells) in the olfactory bulb can generate lateral inhibition between different glomeruli, and if so, how effectively and over what distance. I am using a CCD system to image olfactory receptor axon terminals loaded with Ca2+ indicators, which allows me to focally activate a single glomerulus within the olfactory bulb and test how this affects subsequent responses in neighboring glomeruli. This will provide more information about how complex spatiotemporal inputs interact with each other during olfactory processing.
Gal Haspel
Ben-Gurion University
Photoactivation of C. elegans neurons
I have just concluded my Ph.D. research on behavior-altering wasp venom with Fred Libersat in the Ben-Gurion University in Israel. This summer, I am trying to develop a method for noninvasive stimulation of C. elegans neurons by expressing three proteins that comprise a photosensitive pathway. Any neuron expressing this system will practically turn into a photoreceptor. A single neuron or a small group of neurons could be exclusively excited and correlated with an induced behavior or cellular activity. The ability to feed neurons or neuronal ensembles with synthetic activity might provide.
Sandy Kuhlman
Cold Spring Harbor Laboratory
Role for fast GABAergic transmission in promoting synaptic competition
Inactivity induced by visual deprivation during a "critical period" of early postnatal life leads to competitive interaction between eye inputs and selective weakening of deprived inputs onto binocular neurons. With my advisor Z. Josh Huang, and here as a Grass Fellow, I am using whole-cell recordings in brain slices of mouse visual cortex to establish that maturation of inhibition mediated by fast-spiking, parvalbumin interneurons contributes to the onset of plasticity, and gives the open-eye pathway a competitive advantage to drive post-synaptic targets to spike threshold. Additional interests include: circadian rhythms generation and entrainment by light.
Anthony J. A. Molina
University of Illinois at Chicago
The role of extracellular pH microdomains in visual processing
As a graduate student in the laboratory of Robert Paul Malchow, my work has focused on understanding the mechanisms involved in the processing of visual information. My Grass Fellowship project looks into the presence of extracellular H+ microdomains which could provide novel insights into the role of retinal horizontal cells in contrast enhancement. This summer, I am working at the BioCurrents Research Center with Peter Smith, utilizing pH sensitive self-referencing microelectrode technology to measure proton fluxes from isolated skate retinal neurons. In addition, I am combining these techniques with calcium imaging and calcium uncaging with UV laser coupled optical fibers.
Jennifer R. Morgan
HHMI / Yale University School of Medicine
Mechanisms of Actin Regulation at the Synapse
I am a postdoc in Pietro De Camilli's lab, where I study synaptic vesicle recycling and its regulation by the actin cytoskeleton. I use the large reticulospinal synapses of the lamprey as a model system, because there exists a prominent ring of actin surrounding vesicle clusters that can be visualized with fluorescent markers. Previously, I found that KCl stimulation causes gross rearrangements of synaptic actin. This summer, I am monitoring the movements and intensity changes of actin during action potential stimulation as a way of elucidating the role of actin during synaptic vesicle recycling.
Gabe J. Murphy
UCSD School of Medicine
Mechanisms of Feedback Inhibition in the Retina
I am a graduate student in Jeff Isaacson's lab; together, Jeff and I have explored several unique features of synaptic transmission in the rodent olfactory bulb. This summer, I have examined the process by which GABA released from amacrine cell dendrites modulates glutamate release from presynaptic bipolar terminals in slices of the goldfish retina. I exploited the unusually large (~10 µm) goldfish bipolar terminals to examine directly, via whole cell patch clamp recordings, the modulation of ion currents that trigger glutamate release by GABA receptor-activated conductances and effectors.
Joseph A. Sisneros
Cornell University
Steroid-dependent plasticity of auditory hair cell tuning in the plainfin midshipman, Poricthys notatus
I am currently a research associate in the lab of Andy Bass investigating the adaptive auditory plasticity of peripheral frequency sensitivity in the plainfin midshipman. The principal goal of my summer project is to characterize the frequency response dynamics of hair cell microphonic potentials from the midshipman sacculus (the main auditory inner ear end organ in the midshipman) and test the hypothesis that the steroid-dependent plasticity of saccular afferent tuning is paralleled by plasticity in the electrical tuning of auditory hair cells.
Carlos A. Villalba-Galea
Duke University Medical Center
The timing of protein-protein interactions involved in synaptic vesicle endocytosis
David G. Zeddies
Loyola University - Chicago
Optical measurement of auditory brainstem response in larval zebrafish
I am currently a postdoc with Richard (Dick) Fay and have been investigating the startle response in zebrafish. I am interested in how fish process acoustic information, but little is known about the capabilities of larval zebrafish. This summer I am trying to determine the frequencies and lowest level sounds that larval zebrafish could hear. To do so, I am attempting to obtain optical measurements of activity in auditory brainstem neurons using calcium sensitive dyes.
Susan Barry
Grass Fellowship Program Director
Associate Professor
Mount Holyoke College, Department of Biological Sciences
Clapp Laboratory, South Hadley, MA 01075-6410
email: sbarry@mtholyoke.edu
Ion currents in protists
Ion channels play a role not only in the generation of the nerve impulse, but also in the behavior of many protists. I study the role of ion currents in the behavior of protists and also the effects of antimalarial drugs on these currents. At MBL, I have been studying the role of ion currents in cytoplasmic streaming and pinocytosis in Amoeba proteus.
Melissa Ann Vollrath
Grass Fellowship Associate Program Director
HHMI/Harvard Medical School, Division of Neuroscience, Boston, MA 02115
Mechanosensation in the squid statocyst
I am a postdoctoral fellow in David Corey's lab. I am interested in mechanosensation and the mechanisms of sensory adaptation. In David's lab I work on hair cells of the mouse and zebrafish. At the MBL I work on squid statocyst hair cells. Despite evolutionary distance and morphological differences in the sensory cells, the statocyst system resembles the vertebrate vestibular system in both form and function. I am using a combination of electrophysiology and histological techniques to elucidate the properties of the mechanosensitive channels and the mechanism of adaptation in squid hair cells.
Darcy B. Kelley
Forbes Lecturer
