A NEW ULTRASONIC METHOD FOR MEASURING MINUTE MOTION ACTIVITIES ON RATS

A new ultrasonic method is presented for measuring the minute motion a ctivities of rats. A pair of low-cost 40 kHz ultrasonic transducers ar e used to transmit ultrasound toward a rat and receive the ultrasound reflected from the rat. The relative motion of the rat modulates the p hase difference between the transmitted and received ultrasound signal s. An 8-bit digital phase meter was designed to record the phase diffe rence signal which was used to reconstruct the relative motion wavefor m of the rat in an 8751 single-chip microcomputer, The reconstructed d ata are then sent to a PC-AT microcomputer for further processing. Thi s method employs a spectrum analysis for the reconstructed data and ca n measure three minute motion activities including locomotor activity (LMA), tremor and myoclonia. Finally, the method has been tested with real animal experiments. The main advantages of this new method are th at it is non-invasive, non-contact, low cost and high precision. This new method could also be profitably employed for other behavioral stud ies and offer potential for research in basic medicine.