Hemodynamic nonlinearities affect BOLD fMRI response timing and amplitude.

ABSTRACT: The interpretation of functional magnetic resonance imaging (fMRI) studies based on blood oxygen-level dependent (BOLD) contrast generally relies on the assumption of a linear relationship between evoked neuronal activity and fMRI response. While nonlinearities in this relationship have been suggested by a number of studies, it remains unclear to what extent they relate to the neurovascular response and are therefore inherent to BOLD fMRI. Full characterization of potential vascular nonlinearities is required for accurate inferences about the neuronal system under study. To investigate the extent of vascular nonlinearities, evoked activity was studied in humans with BOLD fMRI (n=28) and magnetoencephalography (MEG) (n=5). Brief (600-800 ms) rapidly repeated (1 Hz) visual stimuli were deliv

SUBMITTER: de Zwart JA 

PROVIDER: S-EPMC2731556 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature