Figure 2.

Steps of the activity detection system. Preprocessing steps for raw MREG data: motion correction, brain extraction, image registration, and probabilistic independent component analysis across subjects resulting in components part of the DMN as well. Activity peak detection on each DMN ICA component: reduce cardio-respiratory physiological noise and calculate slow vasomotor fluctuations, clean ICA component from physiological noise, exclude time points and neighborhood affected by head motion, peak detection on clean and motion-free signal. Visualization using data after registration preprocessing step: crop MREG data around activity peaks and extract slices as videos and frame tiles in the spatial region of interest.