Xin Yu1, Benjamin Porter1, Stephen Dodd1, Afonso Silva1, Alan Koretsky1
1NINDS, NIH, Bethesda, MD, United States
Direct characterization of the intracortical changes in vascular elements eliciting BOLD and CBV remains challenging. We measured BOLD and iron oxide based CBV in layer IV/V of the barrel cortex after whisker pad stimulation at high temporal (100msec) and spatial resolutions (150 x150m) using EPI and fast gradient-echo MRI. Low intensity EPI voxels corresponded to activated BOLD voxels and were attributed to venules. Voxels activated using BOLD were non-overlapping with CBV voxels. Fast activations (<500msec) and distinct locations from BOLD voxels led us to attribute these CBV voxels primarily to penetrating arterioles known to vasodilate during increased neural activity.