Our lab studies the relation between synaptic structure and function, with the particular aim of understanding what determines a synapse's strength. Change, or plasticity, in synaptic strength represents communication between cells that is required for normal function; this communication (or lack of it) is strongly implicated in learning, memory and certain disease states. We use electrophysiology, such as voltage and patch clamping, together with three-dimensional confocal and electron microscopy. In particular, we have developed means to visualize and study individual transmitter-containing vesicles as they are released and subsequently reprocessed by nerve terminals.

Image at left: Part of a snake neuromuscular bouton, reconstructed from 13 serial EM sections. Folds in the postsynaptic membrane are blue, the presynaptic membrane is yellow, and the Schwann cell cap is purple. Horseradish peroxidase, HRP was applied to the bath while the bouton exocytosed neurotransmitter in response to 90 stimuli delivered over 30 sec. Compensatory endocytosis, marked by HRP reaction product, was in part clathrin-mediated (white 50 nm vesicles) and in part via bulk membrane internalization (large red endosomes). Some of the endosomes split into smaller ones (also shown red).