The Acoustically Evoked Magnetic And Acoustical Responses Of Auditory System

After accepting the acoustical stimuli the auditory system would responde to it in the forms of the electrical,magnetic and acoustic activities. Nowadays the acoustically evoked electrical respouses are very popular and widely used in clinical diagnosis. But the late dis-coveried auditory magnetic response and distortion product otoacous-tic emission (DPOAE),one of the evoked acoustical responses ,are not so popular as electrical response. This study includs two parts, one was a measurement of acousticallly evoked magnetic field on the normal adults,the other dealed with the physiological characteristics of DPOAE's origin of guinea pigs.Part one —Auditory evoked magnetic fields on the normal adultsIn part one,the instrumentation system detecting and recording AEF had heen established and firstly measured AEF on the normal adults domestically. Under our experimental conditions the 1kH_ztone burst lasting 100ms could induce the stable and clear eight waves on the normal subjects. The deviations of latencies are small. Main wave is N₃ with latency 118ms and magnitude about 150fT corresponding to N_100mwave in the references.Part two—some physiological characteristics of guinea pig's DPOAE.We did three experiments in part two . In our first experiment no changes of guinea pig's DPOAE can he found when brocking the passway from auditory central nerve system to peripheral cochlear system by means of brocking olivocochlear bundle with injection of the strychnine and resecting the auditory nerve. the result suggests that the auditory central nerve system don't participate in and affect on the DPOAE's origin. Under the lower frequeuey and high intensi-...