Experimental Studies Of Pitch Perception On Guinea Pig Body

Voice has three attributed, respectively pitch, loudness and timber. We can enjoy the beauty of music it is because of pitch. But until to now we have not yet figure out the mechanism of pitch. At the beginning of the research, people relate pitch and frequency and think it associated with the frequency of the sound signal, which is supported by function of frequency analysis of auditory periphery. It can perfectly explain pitch of sound only contain one frequency component, but does not explain the pitch of complex tone which contains multiple frequency components. Neuroscience point out pitch associates with the time domain characteristics of the response signal and the nerve system is the place where produce pitch. After nonlinear dynamics methods used in the tone of the study, which explained the pitch shift effect and indicated pitch is processed in the auditory periphery. Above all the explain of the place processed pitch are all theories and no one examine these theories in physiological experiment. If know the nature of pitch, not just promote the technology of artificial cochlea more than diagnosis and treatment of hearing disease. This paper is the first one to research pitch perception on animal body.Through anatomy of guinea pig's head and neck, we explored a new method of the exposure of the cochlea. This new method can ensure dissection guinea pig survived at least 4 to 5 hours and for the subsequent measurement provide enough time. Then after repeated many times on measuring angle adjustment, and think out to make a new fixture based on the old one, and cooperate with the anatomy experiment to a wider range of exposed the cochlea, the introduction of more the outside light and make the irradiation of laser nearly vertical to the basement membrane, such ability can guarantee the follow-up the measured vibration signals effectively. On the basis of our group's research of vitro cochlea which found the second pitch deviation, I solved the above two key problems and make many sounds based on the Psychoacoustics experiment successfully measured biological activity of the vibration response signal of cochlear basement membrane and found the second pitch shift at the help of our lab's heterodyne laser interferometer based on TDC linear. Experimental results are consistent with psychological experiment, which confirmed that the auditory periphery participates in the pitch extraction process.