Kinematic model of brain motion: (a) sagittal view of the tagged MRI with the displacement field superimposed (previously reported in [24]), (b) the experimental displacement field shown at the time of maximum rotation angle at t = 56 ms (reported in [24]), (c) displacement field from the unconstrained rigid-body model at t = 56 ms with the translation of brain CoR superimposed, (d) fringe plot of displacement error for the rigid-body model. (e–g) Time trace of unconstrained rigid-body sagittal rotation, PA translation and IS translation, respectively.