Time frequency plot. The contraction frequencies (dotted line) are illustrated as a function of time. A dominant frequency of 3 min-1 is seen initially as the magnet pill is located in the stomach. At approximately 09:45 the magnetic pill enters the small intestine and the dominant frequency changes to 10 min-1. Ileocecal passage is seen at approximately 13:00 as a drop in frequency to 4-5 min-1. The green color indicates contractions with high amplitudes at a given frequency and the red color indicates contractions with lower amplitudes. The red dots are peak amplitudes obtained when the magnet is performing very slow movements.