Synapses in the central nervous system have the ability to alter the amount of neurotransmitter released within tens of milliseconds. This dynamic quality of the synapse allows for the rapid integration of different types of information. Our laboratory uses a mouse model of the dorsal lateral geniculate nucleus to study the mechanisms of synaptic plasticity important in the developing and mature thalamus. We take advantage of a combination of tools, including electrophysiologic and calcium imaging techniques, as well as genetically altered mouse strains. One area of our research examines the factors important in the formation and refinement of synaptic connections during development. We have characterized the functional convergence of the retinogeniculate synapse during development as multiple inputs are eliminated and the remaining synaptic inputs strengthened. Using this normal developmental sequence for comparison, we have begun to identify and characterize the factors that mediate the refinement of the retinogeniculate connection. We are taking advantage of mouse mutants and pharmacological manipulations to dissect the roles of specific molecular cues and neuronal electrical activity in synapse maturation. Another area of research focuses on the decoding of firing patterns of retinal ganglion cells into the output response of the thalamocortical relay neurons. We are addressing several questions: (1) how do specific retinal firing patterns influence synaptic strength? (2) how do ascending neurotransmitter systems from the brainstem modulate the strength of the retinogeniculate synapse? and (3) how do long term changes in presynaptic activity alter the properties of the retinogeniculate synapse?