Spatiotemporal dynamics of molecular signalling in synaptic function and plasticity

Understanding how neurons process and integrate synaptic inputs, and how these functions may be modified by prior activity, represents a crucial challenge for neuroscience. New methods for optical imaging of molecular sensors can contribute to this understanding by virtue of their high spatial, temporal and chemical resolution. Sensors for many important signaling molecules have not, however, been available; those that are often suffer from signficant limitations including poor specificity and sensitivity, bleaching, and phototoxicity. We will develop new genetically-encoded fluorescent sensors for key intracellular signaling molecules including calcium and other second messengers. We will use these probes in hippocampal and neocortical neurons, in conjunction with high-resolution imaging methods including laser scanning and total internal reflectance microscopy, to investigate the function of specific signaling mechanisms in synaptic transmission, integration and plasticity. Of particular interest are neuronal mechanisms that may be responsible for regulating signal localization and for controlling the transition between transient and persistent modulation of the system.