Optical biology can be broadly defined as the use of light to understand and manipulate cells and molecules. As a group, we are unified by our interest in using optical techniques to study the molecular basis of cell behavior. Most of the proposed members are using variants of light microscopy, including time lapse video imaging, calcium imaging, confocal microscopy, two-photon microscopy, optical trapping, photoablation, release of caged compounds, fluorescence resonance energy transfer (fret), and fluorescence recovery after photobleaching (frap). Collectively, the faculty members in our core group have been successful in establishing themselves as experts in the development of new probes and instrumentation as well as the application of optical techniques in novel ways to neuroscience, immunology, cell biology and biomedical engineering. These methods are being used to monitor intracellular signaling pathways within cells that lead to normal development, movement, and communication within the body.