Enhanced fMRI Response Detection and Reduced Latency through Spatial Analysis of BOLD Signals

In conventional functional magnetic resonance imaging (fMRI) analysis, activation is often inferred by examining only the intensity modulation of blood-oxygen-level dependent (BOLD) signal of each voxel in isolation or in small, local clusters. However, as has been recently demonstrated, activation can in fact be detected by examining the spatial modulation of the BOLD distribution within a region of interest (ROI). In this paper, we propose and demonstrate with real fMRI data that analyzing such spatial changes can enhance the effect size of fMRI response detection over using intensity information alone. Furthermore, we show that such spatial changes consistently and significantly antecede mean intensity changes in multiple ROIs. We hence foresee spatial analysis of BOLD distribution to be a promising direction to explore in complementing pure intensity-based approaches.