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Temporal dynamics and spatial specificity of arterial and venous blood volume changes during visual stimulation: implication for BOLD quantification

By Tae Kim and Seong-Gi Kim


Determination of compartment-specific cerebral blood volume (CBV) changes is important for understanding neurovascular physiology and quantifying blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI). In isoflurane-anesthetized cats, we measured the spatiotemporal responses of arterial CBV (CBVa) and total CBV (CBVt) induced by a 40-second visual stimulation, using magnetization transfer (MT)-varied BOLD and contrast-agent fMRI techniques at 9.4 T. To determine the venous CBV (CBVv) change, we calculated the difference between CBVt and CBVa changes. The dynamic response of CBVa was an order of magnitude faster than that of CBVv, while the magnitude of change under steady-state conditions was similar between the two. Following stimulation offset, ΔCBVa showed small poststimulus undershoots, while ΔCBVv slowly returned to baseline. The largest CBVa and CBVt response occurred after 10 seconds of simulation in cortical layer 4, which we identified as the stripe of Gennari by T1-weighted MRI. The CBVv response, however, was not specific across the cortical layers during the entire stimulation period. Our data indicate that rapid, more-specific arterial vasodilation is followed by slow, less-specific venous dilation. Our finding implies that the contribution of CBVv changes to BOLD signals is significant for long, but not short, stimulation periods

Topics: Original Article
Publisher: Nature Publishing Group
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Provided by: PubMed Central
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