We are interested in the mechanisms underlying spontaneous activity in the developing nervous system and the role this activity plays in the construction of neuronal circuits. There are several examples throughout the developing vertebrate nervous system, including the retina, spinal cord, hippocampus and neocortex, where immature neural circuits generate activity patterns that are distinct from the functioning adult circuitry. It has been proposed that these transitional circuits provide the “test patterns” necessary for normal development of the adult nervous system.

We study spontaneous activity in the immature mouse and rat retina. Mice are born with their eyes closed. Light responses are first detected at postnatal day 10 (P10) and their eyes open at P14. During these first two postnatal weeks, immature retinal circuits spontaneously generate propagating bursts of action potentials termed retinal waves. During this same postnatal period, there is tremendous amount of development within the visual system, including formation of retinal circuits that mediate various light responses, as well as sculpting of retinal projections to their primary targets in the brain. Hence, the developing visual system is a premier model system for studying the role of spontaneous activity in the development of functional circuits.

We use a combination of electrophysiology, imaging, and anatomical techniques to address three major questions:

• What are the cellular mechanisms underlying retinal waves?
• What is the role of retinal waves in the development of retinal projections to the brai?
• How do motion sensitive circuits arise during development?