Optimizing Preprocessing of fMRI Data to Maximize Correspondence of Functional Anatomy Across Individuals
Abstract
In movie-activation fMRI, intersubject correlation (ISC) indicates a functional correspondence across viewers. Brains di↵er in shape; spatial normalization and smoothing enhance inter-subject functional overlap. We compare three normalization methods and six smoothing levels to discover which method yields the best functional overlap, indexed by ISC. This is key to optimizing data analysis in clinical studies using movie-activation fMRI in future. In a 3T scanner, 44 healthy subjects watched an 8-min movie. Both normalization and smoothing a↵ected the strength and extent of the ISC. ISC values were more robust for ANTs and DARTELthanforSPM12andwere(asymptotically)thestrongestat12mmsmoothing. When image data are preprocessed with high-dimensional volumetric spatial registration methods, such as ANTs, and 12mm smoothing, the sensitivity of the movie-fMRI paradigm will be optimal for detecting abnormalities in presurgical evaluation of neurological patients, providing lessvariableandmorereliableISCmeasures.