In MRI experiments, we usually ask our participants to keep still in the scanner because head movement may affect the data quality. Meanwhile, we always do the motion correction before fMRI/rfMRI data preprocessing, aiming to reduce the potential influence of this unwanted noise. However, recent studies showed that there were motion effects even after the motion correction with the standard algorithms. For example, the artifact of participant motion affects the functional connectivity analysis of rfMRI data. In addition, head motion can also result in a bias for the calculation of both FA and MD in DTI data analysis.

Though the head motion causes us unwanted trouble, the parameters of head motion may be interesting since they are found to be stable across time. Hence, we may ask two following questions. 1. What is the psychological correlation of head motion? 2. What is the neural correlation of head motion?

For the first one, we may search some basic psychological measures, e.g., attention, impulsive control, to test the correlation relationship. For the second one, it may be hard to answer with only MRI data. Because we are not sure that the correlation is the neural basis or just the artifact of head motion.