Development of Photoreceptor Connectivity

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

Our visual abilities arise from the capacity of photoreceptor cells to transduce a photic stimulus into a neural response and to transmit this message to second order neurons. Effective transmission of that message is, in turn, dependent on processes acting during development that orchestrate the formation of the retinal circuitry. However, relatively little is known about the developmental mechanisms responsible for establishing the precise connectivity of photoreceptor cells. The present investigation will identify cellular and molecular mechanisms controlling the formation of photoreceptor connectivity in the developing ferret retina. Preliminary data indicate that photoreceptor terminals initially grown beyond their normal targets in the outer plexiform layer and that the errant terminals are subsequently retracted as proper connections are formed. This proposal will define the transitional morphology of photoreceptor terminals during the period of synapse elimination. Moreover, cellular and molecular mechanisms controlling terminal outgrowth, target recognition, and synaptic connectivity will be identified using in vivo experimental manipulations and in vitro approaches. These studies should clarify the mechanisms by which the changing circuitry associated with photoreceptors is established during development.