以電腦模擬方式探討橄欖-耳蝸反射迴路之反遮蔽效應

Exploring the unmasking effects of medial olivocochlear reflex pathway by computer simulation

邱國捷(Kuo-Chieh Chiu)

指導教授 ： 劉奕汶

國立清華大學/電機資訊學院/電機工程學系/碩士(2012年)

摘要

本論文主要目的在模擬聽覺的生理現象―遮蔽效應及反遮蔽效應，遮蔽效應及反遮蔽效應對人耳的幫助甚大，遮蔽效應及反遮蔽效應都可以藉由內側橄欖耳蝸中繼神經元(Medial Olivocochlear,MOC)對外毛細胞產生影響所造成，MOC有一條負迴授連接至外毛細胞，當基膜上的振幅過大使得聲音強度增強到可能損害聽力系統時，MOC會做出抑制，讓外毛細胞之電動性便因此降低，基膜的振動程度也因此變小，造成聽神經產生的動作電位次數降低，以達到保護聽力的作用，此為遮蔽效應的功能；至於反遮蔽效應則為在有噪音的環境中，當有MOC抑制的情況下，可對噪音產生較大抑制而對語音訊號產生較少抑制，因此即使在有噪音的影響下，還是能透過此機制的作用，使接收到的訊號更加清晰，這種現象稱為反遮蔽效應。模擬所利用之聽覺迴路模型以Liu and Neely (2009)(2010)所提出的中耳至內耳耳蝸模型為基礎，再連接多個聽覺生理模型，形成一聽覺迴路模型，並期望透過此模型調整模型參數來模擬經過MOC之聽覺反射對基膜上行進波的影響，以及受到MOC影響後的聽神經觸發次數的變化，以期望在聽力診斷與聽覺心理學(psychoacoustics）上有所貢獻。

關鍵字

反遮蔽效應 ； 內側橄欖耳蝸中繼神經元

並列摘要

The main purpose of this thesis is to simulate human’s ear hearing physiological phenomena-the masking effect and unmasking effect. Both of these two are helpful for our ears, which are able to use the medial olivocochlear(Medial Olivocochlear, MOC) to affect outer hair cells. MOC has a negative feedback which connects to outer hearing cells. Our hearing system might be damaged when the amplitude on the Basilar Membrane is too large. Hence, the MOC will suppress it and the motility of outer hearing cells would be reduced so that the vibration of Basilar Membrane would also calm down. This results in decreasing the number of the action potentials made by our hearing nerves. In this way we are able to protect our hearing system. The mentioned above is so-called masking effect.On the other hand, as for the unmasking effect, while we are exposed to the noisy environment, we can have more suppression for the noise and the less suppression for the letters if we get the MOC. As a result, even if we are in a noisy place, we can still use this to make the letter we received much clearer, and that is unmasking effect.This researching model is based on the middle ear to the cochlea, which was referred by Liu and Neely(2009)(2010), and then it combines with a variety of models for our physiological hearing, eventually leads to a hearing pathway model.Right now we are looking forward to using this model (change some parameters if needed) to simulate the effect of Basilar Membrane by using MOC, and then we see the situation of the hearing nerves effected by MOC. Hopefully, we expect to give some devoting to the hearing diagnosis and the psychoacoustics.

並列關鍵字

unmasking effect ； Medial Olivocochlear

參考文獻

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