EMG Recording And Analyzing In Vivo For Free-moving Small Animals

Making the most of animal’s motor function and power supply system, a bio-robot can completeparticular tasks that humans are not able to fulfill or are afraid of doing. We people achieve artificiallycontrol of animal’s movement and certain behaviors with biological information processing as the coreand starting by motor innervations. Compared with conventional robot, bio-robot has unparalleledadvantages in terms of the flexibility and robustness of movement and energy supply. Collection andanalysis of electrical nerve signals from prototype animal is a basic and important work in theresearch of animal robot.A wireless EMG in vivo collection and storage device for free-moving animals was developed.The size of the device was3.2cm×2.5cm×1cm (L×W×H) with12g. Analog signals of five channelscould be sampled at1KHz/s simultaneously for more than2h. EMG would be collected into a4GBTF card. These features made it appropriate to be equipped in animals, avoiding external interferenceof lined mode. In the meanwhile, working radius was larger than that of RF mode. Then EMG fromtwo sorts of animals in different situations with the device was recorded. EMG of flexor tibialisexternus and ambiens in gekko’s running periods was recorded to analyze their antagonism. EMG offour-limb flexors was recorded when gekko was in a relatively quiescent state to explore the impact ofbody position on limb’s motion. Pigeon’s optimum load pattern and load limit during takeoff were alsoinvestigated. Based on this result, EMG from pectoral muscle was also collected with the pigeoncarrying loads when it took off, exploring muscle’s firing characteristics with different loads.EMG collecting experiments on two sorts of small animals showed that the device could be usedto collect EMG from several areas of the body in free-moving animals. Experiments on gekko geckoindicated that flexor tibialis externus and ambiens showed antagonism in a way. Relative to thehorizontal and vertical state, firing activity of limb flexor was more obvious when gekko was in tiltedstate. Experiments on pigeons showed that when taking off with loads, keel was the best positionwhich could carry more loads, and its limit load was about25%～28%of body weight. Firingintensity of SB was higher than that of TB. And the heavier the loads were, the shorter the firinginterval was. This subject provided a powerful tool and a reference for in-depth study of animalrobots.