OBSERVATION ON THE CHANGES OF THE ENDOCOCHLEAR D.C. POTENTIAL UNDER TONE STIMULATION
1963 Volume 66 Issue 1 Pages 47-57
Details
1963 Volume 66 Issue 1 Pages 47-57
By piercing a microelectrode through roundwin-dow membrane, influence on the endocochlear d, c. potential of guinea pigs under acoustic stimulation was studied experimentally, and the following re-sults were obtained.
1) By acoustic stimulation, changes of endoco-chlear d. c. potential were observed in both peri-and endolymphatic space, and both in per- and pos-tstimulatory period in spite of duration and frequ-ency of stimulus tone.
2) In endolymphatic space the endolymphatic d.c. potential decrease by tone stimulation.
The course of these changes were generally as follows : as the tone is begun the d.c. potential falls rectangurally and then exponentially decre-ases, and when the tone is stopped the potential rises rectangurally and then exponentially increases to the original value of the potential.
But sometimes even in normally (fresh prepara-tion?) the endolymphatic d.c. potential increases responding to low frequency and weak intense sou-nd.
3) The latency of these changes was very short as C.M. and could not measured.
4) The changing value of this potential was li-near at weak intense sound, but over about 75db S.L. become nonlinear. Those value were larger than low frequency tone under same sensation le-vel.
5) In perilymphatic space (scala tympani) thepoalrity of this phenomenon was antagonistic and the value was smaller than in the endolymphatic space (about 1(8). The course of this phenomenon in perilymphatic space was like that of the endo-lymphatic space under low frequency tone, but un-der higher frequency tone the wave form becomes similar to the envelop curve of the stimulus tone.
6) At asphyxia, changing value of this pheno-menon becomes smaller as decrease of endolym-phatic potential, and defficiency of oxygen became higher, and this d.c. potential becomes negative relative to perilymphatic potential. Just at this ti-me the polarity of this phenomenon changes to the opposit side. From these results author considers the Summating Potential to be the changes of endo-cochlear d.c. potential under tone stimulation and those changes are observed also in poststimulatory period
