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Mechanisms Governing Signal Propagation and Processing in Sensory Systems
Summary: Gabe Murphy explores biophysical properties of synapses and neurons that underlie the specificity and fidelity with which neural circuits represent information about sensory stimuli.
Our perception of the external world is shaped and limited by the fidelity with which activity in neural circuits encodes information about sensory cues. The research in my lab focuses on identifying mechanisms governing the accuracy and precision with which activity in the mammalian retina reflects spatial and/or temporal features of light stimuli.
We focus on the retina for several reasons. First, spatiotemporal patterns of neural activity in the output cells of the retina, retinal ganglion cells (RGCs), are important—they form the basis for visual perception. Moreover, distinct sets of RGCs differ in their responses and sensitivities to features of light stimuli, and many of these functional differences persist in in vitro preparations of the retina; performing experiments in vitro, on an intact circuit that responds to physiological stimuli, allows us to precisely measure and perturb sensory signals in well-defined parallel circuits.
Expressing fluorescent proteins in specific neurons, identifying these neurons via multiphoton excitation fluorescence microscopy, and performing simultaneous patch-clamp recordings from multiple cells in the retina provides an unusually good opportunity to connect the contribution of specific biophysical properties in specific neurons directly to the properties of neural activity elicited by physiological stimuli.
The same set of techniques, moreover, enables us to assay and manipulate properties of synapses, cells, and circuits with greater precision than would be possible with light stimuli alone. Our hope is that combining these (and other) approaches will (1) provide powerful insight into mechanisms governing the transformation and representation of information in distinct retinal circuits and (2) reveal general principles governing signal propagation and processing throughout the central nervous system.
Last updated: August 15, 2008
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