Retinal waves: mechanisms and function in visual system development

A characteristic feature of developing neural networks is spontaneous periodic activity. In the developing retina, retinal ganglion cells fire bursts of action potentials that drive large increases in intracellular calcium concentration with a periodicity of minutes. These periodic bursts of action potentials propagate across the developing inner retina as waves, driving neighboring retinal ganglion cells to fire in a correlated fashion. Here we will review recent progress in elucidating the mechanisms in mammals underlying retinal wave propagation and those regulating the periodicity with which these retinal waves occur. In addition, we will review recent experiments indicating that retinal waves are critical for refining retinal projections to their primary targets in the central visual system and may be involved in driving developmental processes within the retina itself.