Rowland Taylor, Ph.D.
Research in the Taylor Laboratory
Light intensities in the natural environment cover a range many orders of magnitude larger than the dynamic range of neurons in the visual system. A major function of the retina is to constantly adapt to the changing visual input, and send the brain a compressed representation of the retinal image, that is largely invariant to changes in the intensity or spectral quality of that image. Our goal is to understand how the retinal image is encoded in the output from the retina, and to determine how the circuit structure and synaptic function generate that output. Parallel processing is a key organizing principle for retinal circuits. The retina doesn't generate a single high-fidelity representation of the visual image; rather it simultaneously generates 20 images, each encoded in the activity of specific classes of retinal ganglion cell. In this way the limited signaling bandwidth of each retinal ganglion cell is devoted to signaling a small portion of the visual information. With less information to transmit, each ganglion cell can transmit that information with higher fidelity.
To determine what information each class of ganglion cell transmits and how it extracts that information from the retinal image, we study the mammalian retina, which can be isolated intact, maintained in vitro, and stimulated naturally with images generated on a computer display. We make electrophysiological recordings of the spike output from the retina, generated in the retinal ganglion cells by light stimuli. We also measure the light-evoked signals that carry the visual information through the retinal circuitry by making patch-clamp recordings of the excitatory and inhibitory post-synaptic currents, and post-synaptic potentials, within all classes of retinal neuron.
Neural function is ultimately determined by the cellular and sub- cellular expression and distribution of various transmitter receptors and other proteins within the neural pathways. We use immunohistochemistry and confocal microscopy to map the occurrence and distribution of proteins within the retinal circuits. These anatomical and electrophysiological results provide the basis for constructing realistic computer-models of the neural circuits. We can then use the models to test hypotheses regarding function, and make quantitative predictions that can be tested by further experiment.
NIH funded postdoctoral positions are currently available for qualified neuroscientists. Patch-clamp or imaging experience is desirable. Email Dr. Taylor with a statement of research interests and experience, a copy of your CV, and contact details for references.