Involvement of region-specific HRF in classical analysis of event-related fMRI data

The shape of hemodynamic response function (HRF) as it is measured by fMRI is influenced by many factors. Even the time course of neuronal activity by itself does not necessarily trace the time course of fMRI experimental stimulation. The analysis of fMRI data based on assumption of commonly considered (fixed) HRF shape may therefore be mismatched due to inaccurate modeling. Therefore, to formulate more accurate models, by using estimated region-specific HRF for particular volume elements of the brain, may be beneficial. The aim of this paper is to verify the methodology, which involves HRF estimations, in comparison to the classical form of fMRI data analysis. For estimations of HRF was chosen regression method with a modified set of FIR basis functions.