FUNCTIONAL MRI BOLD SIGNAL COINCIDES WITH ELECTRICAL-ACTIVITY IN THE RAT WHISKER BARRELS

Functional MRI (fMRI) provides a noninvasive method for mapping brain functional activity based on blood oxygenation level dependent (BOLD) image contrast that is primarily due to localized increases in perfusi on. Recently, Malonek and Grinvald (Science 272:551-554, 1996) suggest ed that during sustained functional activation, the increases in perfu sion were spread over a much larger area than the localized electrical activity. In this study, it is demonstrated that the spatial distribu tion of the BOLD fMRI signal during sustained stimulation of rat whisk ers has the same spatial pattern and dimension as that of neuronal ele ctrical activity in the rat whisker barrels.