Figure 2.

Principal component analysis of rigid-body motion based on tagged MRI data [24]: (a) 3DOF motion of brain in the sagittal plane is shown for the three subjects. There is a strong correlation between the 3DOF such that it can be approximated by a single DOF, (b) first few principal components for the rigid-body motion are shown as the ratio of total variance. The first principal component accounts for over 75% of total variance, (c) relative rigid-body rotation of brain determined by the model given the skull rotation as input. (Online version in colour.)