Flaum Eye Institute

William H. Merigan, Ph.D.

Research Director
Flaum Eye Institute
Professor of Ophthalmology, Visual Science, and Brain and Cognitive Sciences

Research Insterests

Primate Retinal Ganglion Cells

My research examines the role of retinal ganglion cells in visual perception in the primate (human and macaque). The primate retina contains at least 14 different types of retinal ganglion cells, and each type forms a complete network across the retina. Because the size, shape andprojections of each of the cell types is distinctive, it is thought that they may play quite different and possibly independent roles invisual function,but at present relatively little is known about this question. Some clues about possible functions of different ganglion cell classes comes from their structure (some extend across large swaths of retina, while others get input from tiny regions of retina), their physiology (some ganglion cells respond to color, while others are color blind), and their projections into the brain (some ganglion cells project to visual cortex while others reach the superchiasmatic nucleus, which is thought to be important in diurnal rythyms).

I have used a wide range of experimental methods to examine ganglion cells including psychophysical testing of vision in macaque and humans, electrophysiology and study of the effects of visual system lesions in macaques and humans. Most recently, in collaboration with David Williams, PhD, at the University of Rochester I have been using in vivo adaptive optics imaging to generate near micron scale images of retinal cells and blood vessels. I have also been collaborating with John Flannery, PhD, at the University of California, Berkeley, to use viral vectors to insert gene products into retinal ganglion cells, in order to further explore their function. An ongoing project with Richard Libby, PhD, examines changes in retinal vasculature, ganglion cells and nerve fiber layer caused by glaucoma. Projects with Shakeel Shareef, MD, use search eye movements and adaptive optics imaging to examine the retina of glaucoma patients.

Selected Ongoing Projects

Imaging the physiological activity of macaque ganglion cells with G-caMP, a calcium indicator

Creation of photosensitivity in ganglion cells with channelrhodopsin 2

In vivo adaptive optics imaging of autofluorescent retinal ganglion cells

The role of identified retinal ganglion cells in macaque search eye movements

3D structure of radial peripapillary capillaries in the retina of glaucoma patients

Completed projects

Fluorescence in vivo adaptive optics imaging of dendrites and axons of retinal ganglion cells (Rhod cell)

Transfection of primate retinal ganglion cells with gene products (GFP RGCs)

Vasculature of the primate retina

Fluorescein and indocyanine green imaging of primate radial peripapillary capillaries (RPCs)

Selected References

Scoles, D., Gray, D.C., Wolfe. R., Gee, B., Geng. Y., Masella B., Hunter, J J., Libby, R. T., Russell, S., Williams, D.S., and Merigan, W.H. (submitted) In-vivo imaging of retinal nerve fiber layer vasculature: relevance to glaucoma.

Morgan, J.I.W., Hunter, J., Masella, B., Wolfe, R., Gray, D.C., Merigan, W.H., Delori, F. C., Williams, D.R., (in press), Light-induced retinal changes observed using high-resolution autofluorescence imaging of the retinal pigment epithelium, Investigative Ophthalmology and Visual Science.

Gray, D.C., Wolfe. R., Gee, B., Scoles, D., Geng. Y., Masella B., Dubra, A., Luque, S., Williams, D.S., and Merigan, W.H. (2008) In vivo imaging of the fine structure of rhodamine labeled macaque retinal ganglion cells, Investigative Ophthalmology and Visual Science. 49, 467-473.

Hayes, R.D. and Merigan, W. H. (2007) Mechanisms of sensitivity loss due to visual cortex lesions in humans and macaques. Cerebral Cortex.17, 1117-28.

Gray, D.C., Merigan W.H., Wolfing, J. I., Gee, B., Dubra, A., Porter, J., Twietmeyer, T., Ahmad. K., and Williams, D.R., Tumbar, R. and Reinholz, F., (2006) In vivo fluorescence imaging of primate retinal ganglion cells and retinal pigment epithelial cells, Optics Express. 14, 7144-7158.

Lab members

Jennifer Strazzeri
Bernard Gee
Lu Yin

Collaborators

David Williams, PhD, Center for Visual Sciences, University of Rochester,

Richard Libby, PhD, Flaum Eye Institute

Shakeel Shareef, MD, University of Rochester Eye Institute

John Flannery, PhD, Vision Science, and Molecular and Cell Biology, Division of Neuroscience, University of California, Berkeley

PubMed Search

PubMed search results for Dr. Merigan