Mechanisms Underlying the Refinement of the Retinogeniculate Synapse

Abstract Essential for normal neurological function is the proper formation of neuronal circuits. This process starts with mapping of presynaptic neurons to the proposed postsynaptic partners. In some areas of the brain, initial mapping is precise to the specific postsynaptic cell. In others, like sensory inputs onto primary thalamus, initial targeting of presynaptic axons is broad, followed by synapse pruning and strengthening. This process of modification of the initial connection is referred to as developmental synapse refinement or remodeling. The retinogeniculate synapse, the connection between retinal ganglion cells (RGCs) and thalamocortical (TC) neurons in primary visual thalamus, has been a powerful experimental system for identifying and understanding the cellular, circuit, and molecular mechanisms underlying developmental refinement. This chapter reviews the current understanding of the mechanisms underlying postnatal development that lead to the mature thalamic circuit for sensory processing in the mammalian central nervous system.