Abstract
Our understanding of retinal physiology has come mainly from microelectrode recordings of retinal cells in a dish. However, even the most densely packed microelectrode arrays have limited spatial resolution and require the tissue to be maintained in an artificial environment. High-resolution in vivo optical recording can overcome both these limitations. By imaging many cells simultaneously, sparse cell types that are rarely encountered with a microelectrode can be studied. Moreover, an optical approach deployed in the living animal can track retinal changes over extended time periods, an advantage for studying the progression and treatment of retinal disease. We have developed a fluorescence adaptive optics scanning light ophthalmoscope to record visually driven neuronal activity in mouse and monkey retinal neurons that express a genetically encoded calcium indicator. In the primate, GCaMP6 expression in the foveal ring enables us to record from ganglion cells driven by the most central foveal cones; a region previously challenging to characterize using conventional electrophysiological methods. We are now able to present fine grained stimuli with a precision approaching the width of a foveal cone. This has allowed us to map on-center and off-center receptive fields of up to 150 ganglion cells simultaneously as well as to repeat imaging sessions in the same animal for as long as 12 months. Optical recording of single cells in intact animals has the potential to provide new information about the function of specialized retinal circuits and accelerate the development of methods to restore vision in retinal degeneration.
Meeting abstract presented at the 2016 OSA Fall Vision Meeting