Simulating Masking and Anti-masking Effects of the Medial Olivocochlear Efferent Reflex

• Main Authors: Wu, Po-Jui, 吳柏叡
• Other Authors: Liu, Yi-Wen
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/78820271484089343907

碩士 === 國立清華大學 === 電機工程學系 === 103 === The masking effect happens when the background noise influences the target sound, which is then difficult to be perceived. To simulated this effect, we constructed a tone-burst-in-noise stimulus, and then fed into the model comprised of middle ear, cochlear membrane-fluid system, outer hair cell (OHC), inner hair cell (IHC), auditory nerve (AN), T-multipolar (TM) cell. This model successfully simulated the masking effect especially in low-level region. The medial olivocochlear reflex (MOCR), a descending auditory pathway, induces the anti-masking effect to reduce the masking effect and help human to perceive sounds. Based on an experiment of the OHC which showed the conductance of OHC was increased after applying acetylcholine (ACh), we have constructed the MOC model by changing the conductance of OHC and simulated the anti-masking effect. The tuberculoventral (TUB) cell is an inhibitory interneuron in dorsal cochlear nucleus (DCN) and projects to the ventral cochlear nucleus (VCN). The TUB inhibits the interneuron in VCN, and is sensitive to tones, while not to noise. We have used these two properties to construct a TUB model and enhance the anti-masking effect in sustained tone-in-noise conditions.