Spontaneous impulse activity of rat retinal ganglion cells in prenatal life.

The existence of spontaneous neural activity in mammalian retinal ganglion cells during prenatal life has long been suspected. This activity could play a key role in the refinement of retinal projections during development. Recordings in vivo from the retinas of rat fetuses between embryonic day 17 and 21 found action potentials in spontaneously active ganglion cells at all the ages studied.