Functional characterization of the developing and adult mouse retina

• Main Author: Stafford, Benjamin K
• Format: Dissertation
• Language: English
• Subjects: biology, neuroscience
• ISBN: 1109289944; 9781109289947

The retina is the source of all visual input into the brain and by understanding how the retina converts photons of light into patterns of electrical activity we can understand the origins of sight. Retinal ganglion cells (RGCs) are the sole output cell of the retina and their electrical activity encodes information about the visual world around us thereby giving rise to conscious vision. Current estimates suggest that there are over 20 RGC types in the adult mouse retina each of which possesses a unique morphology and responds to specific visual stimuli. A precise match between morphology and function, however, is non-existent for many of these cells. This knowledge is important both for understanding how the retina develops---how changes in retinal structure correspond to functional changes---and for understanding how morphology relates to visual processing---how dendritic shape, lamination, and branching density relate to the visual response properties of an RGC. The retina also plays an important role during the development of the visual system. During early post-natal time-points, spontaneous retinal activity, in the form of retinal waves, is widely believed to help shape central projections within the visual pathway. However, the specific features of retinal waves that are important for this process remain a topic of considerable debate. Using large-scale multielectrode array (MEA) recordings, I present analysis of early post-natal spontaneous and adult, light-evoked retinal activity patterns. Through characterization of acetylcholine-driven retinal waves, I found that a previously undetected directional bias, coupled with precisely correlated, high-frequency spiking, work together to drive refinement of retinofugal projections. Through light-evoked recordings, I functionally classified 14 different types of RGCs in the mouse. Further, taking advantage of a unique transgenic mouse, I developed a technique that makes it possible to match, precisely, the function of an RGC with its morphology. With these advances it will be possible to characterize the contributions of specific genes to the development of the retina with unprecedented ease and accuracy.