CHANGING PATTERNS OF SPONTANEOUS BURSTING ACTIVITY OF ON AND OFF RETINAL GANGLION-CELLS DURING DEVELOPMENT

In adult ferrets, retinal ganglion cells (RGCs) responsive to increase d (On) or decreased (Off) illumination convey information to different cellular layers of the dorsal lateral geniculate nucleus (dLGN). Thes e dLGN sublaminae emerge during development when RGCs are found to und ergo correlated spontaneous bursting activity. Using Ca2+ imaging and intracellular dye-filling techniques, we demonstrate here that in ferr et neonates, morphologically identified On and Off beta RGCs have simi lar burst frequencies prior to the segregation of their inputs in the dLGN, but during the segregation period, they develop distinct burst f requencies. Although the bursts of On cells and Off cells occur synchr onously, On cells burst only 25%-35% of the time that Off cells do. Th is change in the temporal bursting patterns of On and Off RGCs may und erlie the segregation of their inputs on dLGN neurons.