[Analysis of colonic motility by fast Fourier transform]

Colonic motility curve was continuously recorded in dog using a strain gauge force transducer and the curve was analyzed by fast Fourier transform. (1) The basic pattern of the colonic motility curve was a gradually increasing and decreasing contractile wave. (2) The frequency components of the basic contractile wave showed a trimodal distribution with peaks at around 1, 20 and 80 mHz. (3) The 1 mHz component showed a sine curve and represented the slow, big motion in the basic contractile wave. (4) The 20 mHz component represented the relatively rapid, gradually increasing and decreasing, big motion in the basic contractile wave. (5) The 80 mHz component represented the rapid, small motion in the basic contractile wave. (6) The fundamental frequency components of the colonic contractile wave were unchanged before and after defecation. (7) For the antiperistaltic wave which disappeared during transmission, the peaks of the wavelength components weakened during transmission and the wave progressed to a multi-modal curve. Our findings indicate that fast Fourier transform is an extremely useful method in elucidating colonic motility.