Jonathan Rizzo Polimeni1, Douglas N. Greve1,
Bruce Fischl1,2,
1Athinoula A. Martinos Center for
Biomedical Imaging, Department of Radiology, Harvard Medical School,
Massachusetts General Hospital, Charlestown, MA, United States; 2Computer
Science and AI Lab (CSAIL), Massachusetts Institute of Technology, Cambridge,
MA, United States; 3Harvard-MIT Division of Health Sciences and
Technology, Massachusetts Institute of Technology, Cambridge, MA, United
States
While
voxels as small as 0.75 mm isotropic provide sufficient SNR for high-field
fMRI, voxels falling within cortical gray matter voxels are still influenced
by partial-volume contamination with white matter and CSF, which contribute
different levels of physiological noise. Here we characterize the impact of
partial-volume effects as a function of cortical depth on the resting-state
fluctuation amplitudes at 7T. Even after partial-volume effects are taken
into account, the magnitude of resting state fluctuations increases with
proximity to the pial surface. This suggests that laminar differences in the
resting-state fluctuations exist and may reflect increasing dominance of
extravascular BOLD signal changes surrounding large pial vessels.