両側皮質聴領剔除後の機能代謝に関する実験的研究
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概要
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The author made a study of functional compensation of hearing acuity after removal of the bilateral auditory cortices in cats, using avoidance conditioning procedure, and explained its mechanism from the electrophysiological point of view.The results are summarized as follow:1) The auditory threshold was fixed at 10 to 20 db above normal hearing threshold one month after removal of bilateral auditory cortices.2) At the time above mentioned, evoked potentials, which were not recognized preoperatively, appeared with auditory stimulation to be recorded from the ventral part of the posterior sigmoid gyrus.The latency of this evoked potential was 10 to 11 msec.3) The auditory threshold did not recover better than 45-65 db loss when bilateral sigmoid gyri with auditory cortices were removed.4) Unitary activities, which were recorded extracellularly with superfine micro-electrodes were found to be"on effect"responses(by Katsuki), being resemble to the type off response of the primary auditory area.However it has more spontaneous discharges and more frequent abolition of response than that of the primary cortical auditory area.5) Abolition of spikes responded to sound stimuli was similarly recognized in intracellular reocrding but excitatory postsynaptic potentials responded constantly to sound stimuli, and indica- ted the arrival of presynaptic volleys to this unit.This phenomenon is considered as the response pattern at the intermediate stage on the way to the completion of con pensatory function.Monakow laid an emphasis on, the release from diaschisis as a mechanism of functional reco- very after brain damage, .and denied the compensation in narrow sense because of the lack of its corroborative evidence.The above mentioned results proved the compensation of auditory function to be exist in narrow sense.
- 社団法人 日本耳鼻咽喉科学会の論文