The absence of task-related increases in BOLD signal does not equate to absence of task-related brain activation

Most fMRI studies employ general-linear-model-based analyses (GLM-BA) of BOLD signal changes to identify regions that are active (or not) during specific cognitive processes. However, alternate analytic approaches (like independent component analysis) may identify more complex patterns of activation, including in regions not implicated in GLM-BA of the same data. In our opinion, fMRI findings revealed by a GLM-BA cannot exclude any brain regions from contributing to specific cognitive processes.