Experimental simulations of motion of the brain at impact were carried out. Rotational accelerations from 2,000 up to 8,000 rad/s2 with durations of 8 to 32 ms were applied to preparations of human skull and brain. The tests were filmed with a high-speed camera with up to 3,000 frames/s. Due to inertia there were relative motion and displacement of the upper part of the brain relative to the skull-cap. Marked displacements (maximum: 2cm) were observed on atrophied brains. Test results are discussed and compared with other investigations.