Functional MRI is an indirect measure of neural activity, as it is the convolution of the hemodynamic-response function (HRF) and latent neural response. Recent studies show variability in HRF across brain regions and individuals, with the potential to confound resting-state functional connectivity (FC) if HRF variability were ignored. Using resting-state fMRI obtained at 7T (N=47), we estimated HRF parameters using deconvolution, and tested the hypothesis that HRF variability confounds FC. We found evidence, with simulations (up to 50% error in FC) and experimental data (mean/median error = 30.5/11.5% in FC) quantifying the impact the HRF variability on FC.
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