Discovery and circuit mechanisms of a retinal ganglion cell with non-canonical receptive field structure

Project: Research project

Description

With the generous support of the KTEF Career Starter Grant, I studied the unusual receptivefield properties of a new retinal ganglion cell (RGC) I discovered called the ‘ON-delayed’ cell (OND RGC), and revealed its synaptic mechanisms. The results are described in a newly published paper in Current Biology [1]. Specifically, the OND RGC’s response latency decreases with stimulus size, and it receives activation by light stimulation away from its dendrites, unlike a canonical ‘center-surround’ organization in RGCs. In addition I observed sensitivity of OND RGCs to small-scale variations (fine details) of projected images, and suggested it may be involved in signaling whether an image is in focus on the retina. This global focus signal is critical for emmetropization and the development of myopia, as well as accommodation in adult animals. Therefore, the role of the OND RGC in these processes is of special interest. However the evidence supporting the role of OND RGCs in emmetropization and accomodation is preliminary, and additional work will be needed to establish this connection. In addition, identification of any components of the retinal circuitry underlying the focus signal (other than OND RGCs) would be a large step in our understanding of myopia development. In the extension of this project, I would like to further explore whether the OND RGC is indeed related to image-focus detection, as well as to potentially find additional (or different) components of the retinal substrate for this signal. To this end I will use multiple, independent methods. I will test whether the OND, or other RGCs, send projections into the Olivary Prestectal Nucleus (OPN), a brain region that may be related to accommodation. I will also keep using electrophysiological recording and pharmacology in retinas of wild type and transgenic mice, to test the role of the unusual receptive-field properties of OND RGCs in
the sensitivity to fine spatial scale in an image.
StatusFinished
Effective start/end date7/1/176/30/18

Funding

  • Knights Templar Eye Foundation, Inc. (AGREEMENT 05/17/17)

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Retinal Ganglion Cells
Myopia
Retina
Olivary Nucleus
Dendrites
Transgenic Mice
Reaction Time
Pharmacology
Light
Brain