Research Interests: Live animal imaging, Two-photon excitation microscopy, Coherent anti-Stokes Raman Scattering (CARS) microscopy, Multiple Sclerosis
Multiple Sclerosis is a progressive, neurodegenerative disorder that results in the destruction of myelin in both the brain and spinal cord. Myelin provides a protective and electrically insulating layer to axons of neurons. At disease onset, the permeability of the blood-brain barrier increases, which allows for cells of the immune system to penetrate the central nervous system and initiate the sequence of events that lead to destruction of myelin. It is the loss of myelin that precipitates the debilitating clinical symptoms observed in MS.
Magnetic resonance imaging (MRI) can indirectly measure myelin and axonal damage with a technique known as Diffusion Tensor Imaging (DTI), which is based on the macroscopic measurement of water diffusion along prescribed directions in the nervous system. Changes in the diffusion of water transverse to and along the axon of a neuron are early indicators of myelin and axonal damage, respectively. Building on ideas from DTI, I am developing an optical technique that will provide cellular measurements of water diffusion at microscopic levels. Coherent anti-Stokes Raman Scattering (CARS) microscopy will be used to image water directly at cellular resolution in vivo. CARS microscopy relies on the precise tuning of two lasers that can excite a chemical resonance in the OH vibration of water. Diffusion coefficients of water with micrometer resolution will be achieved by studying fluctuations in a signal from fixed focal volume to infer the diffusion of molecules in and out of that volume (i.e., correlation spectroscopy).