A fundamental question in neuroscience is how individual synapses and neurons act in concert to create functional circuits. While the basic mechanisms of synaptic transmission between neurons are well understood, much less is known about how individual synapses, neurons, and circuits dynamically adjust their transmission properties in response to perturbations in network activity. During the past few years I have begun a new line of research: the regulation of neurotrophin vesicle release and its effect on synaptic plasticity and learning and memory. These discoveries come at a crucial time, given mounting evidence that BDNF and other neurotrophins and neuropeptides affect synaptic plasticity, while at the same virtually nothing is known about the regulation of their release and the mechanisms by which they affect synapse and circuit function. To continue this research I would like to form my own research group. I am interested in the mechanisms by which individual synapses and neurons respond to changes in activity to modify circuit function and ultimately behavior. I investigate the mechanisms of activity-dependent plasticity at three different levels: single synapses, single cells and neuronal networks, using a combination of manipulation of protein expression and function, biochemistry, electrophysiology and live imaging approaches in neuron cultures and brain slices. My overall goal is to understand how neurons communicate changes in activity to affect circuit function.