Auditory Control Mechanism

1. The Relation of Loudness Growth to Interaction and Feedback Effect in the Cochlear Level

Abstract

On the supposition that the control mechanisms in cochlear level are “interaction” and “negative feedback system”, based on the morphological and physiological evidences, the mechanism of loudness-growth is analyzed by our datum of the “equal loudness contour” on sone scale for the short tone duration's function. Results are as follows:
1) Interaction and negative feedback effect are able to be caliculated quantitatively from the loudness of short tone on each intensity and duration.
Interaction has no concern with the duration of the tone. However, it has linealy concern with the intensity of the tone. Summation is resulted for the tone of less than 30dB SL and inhibition for the tone of 30dB SL and more.
On the other hand, negative feedback effect increases linealy as the function of product of the intensity by the duration of a tone within the range 10dB to 60dB SL.
2) As a result of the combination of two inhibitions, without pathological adaptation, it's easily understandable that every kind of recruitment (incomplete, over and delayed type or hobble effect) should be observed on the inner ear lesion.
3) To measure the slope of temporal and equal loudness curves on the short tone durations the grade and space pattern of the lesion on the cochlear receptors and innervations are brought to light, because the slope of loudness curve is variable by the temporal summation of feedback effect and the stage of loudness curve indicates the strength of the interaction.