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Abstract #1124

Characterization of the BOLD Hemodynamic Response Function at 7T: Towards Separation of Vasculature and Parenchyma

Jeroen Cornelis Siero1, Natalia Petridou2,3, Johannes Marinus Hoogduin2, Nick F. Ramsey1

1Rudolf Magnus Institute, University Medical Center Utrecht, Utrecht, Netherlands; 2Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 3SPMMRC, University of Nottingam, Nottingam, United Kingdom

A limitation of T2*w BOLD fMRI is the confounding contribution of signal from the larger vasculature. Based on time-to-peak and full-width-at-half-maximum BOLD characteristics of different vascular compartments identified at 3T, we characterized the spatio-temporal properties of the BOLD response at 7T in the visual cortex using an event-related fMRI paradigm with short visual stimuli, high sampling rate, and multiple spatial resolutions. For the smallest voxelsize a high time-to-peak spatial heterogeneity of the BOLD response was observed with fast responses localized in parenchyma. This opens the possibility to use TTP to probe layer specific BOLD responses in the human brain.