Analysis of functional MRI time‐series

TLDR

Autocorrelations are inherent in fMRI data because of the hemodynamic response function and the temporal point spread function. The study presents a method to detect significant, regionally specific correlations between sensory input and the brain’s physiological response using fMRI. The method tests correlations between sensory input and the hemodynamic response by convolving the input with an estimated HRF derived without prior assumptions, and applies a cross‑correlation statistic within a statistical parametric mapping framework that accounts for intrinsic autocorrelations. © 1994 Wiley‑Liss, Inc.

Abstract

Abstract A method for detecting significant and regionally specific correlations between sensory input and the brain's physiological response, as measured with functional magnetic resonance imaging (MRI), is presented in this paper. The method involves testing for correlations between sensory input and the hemodynamic response after convolving the sensory input with an estimate of the hemodynamic response function. This estimate is obtained without reference to any assumed input. To lend the approach statistical validity, it is brought into the framework of statistical parametric mapping by using a measure of cross‐correlations between sensory input and hemodynamic response that is valid in the presence of intrinsic autocorrelations. These autocorrelations are necessarily present, due to the hemodynamic response function or temporal point spread function. © 1994 Wiley‐Liss, Inc.