THALAMIC RELAY OF SPONTANEOUS RETINAL ACTIVITY PRIOR TO VISION

Before vision, retinal ganglion cells produce spontaneous waves of act ion potentials. A crucial question is whether this spontaneous activit y is transmitted to lateral geniculate nucleus (LGN) neurons. Using a novel in vitro preparation, we report that LGN neurons receive periodi c barrages of postsynaptic currents from the retina that drive them to fire bursts of action potentials. Groups of LGN neurons are highly co rrelated in their firing. Experiments in wild-type and NMDAR1 knockout mice show that NMDA receptor activation is not necessary for firing. The transmission of the highly correlated retinal activity to the LGN supports the hypothesis that retinal waves drive retinogeniculate syna ptic remodeling. Because LGN neurons are driven to fire action potenti als, this spontaneous activity could also act more centrally to influe nce synaptic modification within the developing visual cortex.