Apparent water diffusion measurements in electrically stimulated neural tissue

The effect of stimulation on diffusion characteristics of electrically stim ulated neural tissue was examined. Bullfrog nerves and spinal cords were ex cised and stimulated electrically during magnetic resonance imaging, and th e apparent diffusion coefficients (ADCs) of water parallel and perpendicula r to the long axes of the specimens were mapped with and without stimulatio n of the tissue. Electrophysiological recordings were used to determine the viability of the tissue after each experiment. No stimulus-related ADC cha nges were observed in either the peripheral nervous system or the central n ervous system tissue. These experiments may help to define further the natu re of previously reported ADC changes in stimulated neural tissue in situ. (C) 1999 Wiley-Liss, Inc.