Time-resolved analysis of fMRI signal changes using Brain Activation Movies

Abstract

Conventional fMRI analyses assess the summary of temporal information in terms of the coefficients of temporal basis functions. Based on established finite impulse response (FIR) analysis methodology we show how spatiotemporal statistical parametric maps may be concatenated to form Brain Activation Movies (BAMs), dynamic activation maps representing the temporal evolution of brain activation throughout task performance. These BAMs enable comprehensive assessment of the dynamics in functional topology without restriction to predefined regions and without detailed information on the stimulus paradigm. We apply BAM visualization to two fMRI studies demonstrating the additional spatiotemporal information available compared to standard fMRI result presentation. Here we show that BAMs allow for unbiased data visualization providing dynamic activation maps without assumptions on the neural activity except reproducibility across trials. It may thus be useful in proceeding from static to dynamic brain mapping, widening the range of fMRI in neuroscience. In addition, BAMs might be helpful tools in visualizing the temporal evolution of activation in "real-time" for better and intuitive understanding of temporal processes in the human brain.