The Assembly of Synaptic Circuits in the Mammalian Retina

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Prior to birth, before there is communication with the outside world, the nervous system is spontaneously generating highly patterned activity. Dr. Feller studies this phenomenon in the developing retina. Before vision is possible, neighboring retinal ganglion cells, the neurons of the retina that project to the brain, spontaneously fire correlated bursts of action potentials that propagate across the retina in the form of waves. This correlated activity, termed retinal waves, is required for the proper refinement of retinal projections to targets in the brain. There is a stage of retinal development immediately preceding eye-opening during which retinal circuits gradually transition from generating retinal waves to mediating light-evoked responses that are the first stage of visual processing. During this transition, these two functional circuits coexist for several days. Two questions regarding this critical stage of development, when the retina itself may be highly plastic are addressed. First, how are retinal waves generated? Sophisticated physiology and imaging experiments will be conducted on acutely isolated mouse retina are used to identify the circuit that underlies retinal waves. Second, how do retinal waves and light-evoked responses interact to determine the firing pattern in the retina? A specialized array of electrodes will be used to record simultaneously from dozens of retinal ganglion cells to determine the interaction between the circuits that mediate waves and light-evoked activity. These experiments will help to better understand the role of spontaneous vs. sensory driven activity in the assembly of neural circuits. In addition, the funds from this project will support the training of two young scientists who are new to Neurobiology. The first is a postdoctoral researcher, Anastasia Anishchenko, who received her Ph. D. in theoretical physics. The second is graduate student, Aaron Hamby, who is trained as a molecular biologist. In addition, the results of this research will be used as material for an undergraduate course on developmental neurobiology that emphasizes the construction of neural circuits.