Fig. 7.
Identified brain activation and superficial artifacts from the systematic fluctuations based on voxel-wise GLM analysis: (a) HbO2-based β-map, (b) Hb-based β-map, (c) HbO2-based t-map, and (d) Hb-based t-map. Each image was thresholded at the corresponding half maxima and half minima. The bigger circle in each image indicates the actual location and size of the simulated brain activation; the smaller circle in each image indicates the actual location and size of the simulated superficial artifacts. The color scales in (a) and (b) represent the real β-amplitude in μM. Images (c) and (d) were normalized by their corresponding maximum or minimum t-values.