Auerbach Benjamin D, Rodrigues Paulo V, Salvi Richard J
Department of Communicative Disorders and Sciences, Center for Hearing and Deafness, University at Buffalo, The State University of New York , Buffalo, NY , USA.
Front Neurol. 2014 Oct 24;5:206. doi: 10.3389/fneur.2014.00206. eCollection 2014.
Sensorineural hearing loss induced by noise or ototoxic drug exposure reduces the neural activity transmitted from the cochlea to the central auditory system. Despite a reduced cochlear output, neural activity from more central auditory structures is paradoxically enhanced at suprathreshold intensities. This compensatory increase in the central auditory activity in response to the loss of sensory input is referred to as central gain enhancement. Enhanced central gain is hypothesized to be a potential mechanism that gives rise to hyperacusis and tinnitus, two debilitating auditory perceptual disorders that afflict millions of individuals. This review will examine the evidence for gain enhancement in the central auditory system in response to cochlear damage. Further, it will address the potential cellular and molecular mechanisms underlying this enhancement and discuss the contribution of central gain enhancement to tinnitus and hyperacusis. Current evidence suggests that multiple mechanisms with distinct temporal and spectral profiles are likely to contribute to central gain enhancement. Dissecting the contributions of these different mechanisms at different levels of the central auditory system is essential for elucidating the role of central gain enhancement in tinnitus and hyperacusis and, most importantly, the development of novel treatments for these disorders.
由噪声或耳毒性药物暴露引起的感音神经性听力损失会减少从耳蜗传递到中枢听觉系统的神经活动。尽管耳蜗输出减少，但在阈上强度时，来自更中枢听觉结构的神经活动却反常地增强。这种因感觉输入丧失而导致的中枢听觉活动的代偿性增加被称为中枢增益增强。中枢增益增强被认为是一种潜在机制，可引发听觉过敏和耳鸣这两种折磨数百万人的使人衰弱的听觉感知障碍。本综述将研究中枢听觉系统中因耳蜗损伤而导致增益增强的证据。此外，它将探讨这种增强背后潜在的细胞和分子机制，并讨论中枢增益增强对耳鸣和听觉过敏的影响。目前的证据表明，具有不同时间和频谱特征的多种机制可能导致中枢增益增强。剖析这些不同机制在中枢听觉系统不同水平上的作用，对于阐明中枢增益增强在耳鸣和听觉过敏中的作用至关重要，最重要的是，对于开发针对这些疾病的新疗法也至关重要。
