William M. Spees1,
2, Tsen-Hsuan Lin3, Sheng-Kwei Song1, 2
1Department
of Radiology, Washington University, St. Louis, MO, United States; 2Hope
Center for Neurological Disorders, Washington University, St. Louis, MO,
United States; 3Department of Physics, Washington University, St.
Louis, MO, United States
Recently, we have implemented diffusion fMRI and demonstrated its utility for detecting white-matter axonal activation in the optic nerve of healthy mice. A robust (27%) and completely reversible stimulus-induced decrease in the apparent diffusion coefficient perpendicular to the axonal fibers was observed with the application of a flashing-light visual stimulus. The change in ADC parallel to the axonal fibers was not statistically significant. The results of hypercapnia experiments suggest minimal contribution from vascular effects.