Ouda Ladislav, Profant Oliver, Syka Josef
Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Prague, Czech Republic.
Cell Tissue Res. 2015 Jul;361(1):337-58. doi: 10.1007/s00441-014-2107-2. Epub 2015 Jan 29.
Aging is accompanied by the deterioration of hearing that complicates our understanding of speech, especially in noisy environments. This deficit is partially caused by the loss of hair cells as well as by the dysfunction of the stria vascularis. However, the central part of the auditory system is also affected by processes accompanying aging that may run independently of those affecting peripheral receptors. Here, we review major changes occurring in the central part of the auditory system during aging. Most of the information that is focused on age-related changes in the central auditory system of experimental animals arises from experiments using immunocytochemical targeting on changes in the glutamic-acid-decarboxylase, parvalbumin, calbindin and calretinin. These data are accompanied by information about age-related changes in the number of neurons as well as about changes in the behavior of experimental animals. Aging is in principle accompanied by atrophy of the gray as well as white matter, resulting in the enlargement of the cerebrospinal fluid space. The human auditory cortex suffers not only from atrophy but also from changes in the content of some metabolites in the aged brain, as shown by magnetic resonance spectroscopy. In addition to this, functional magnetic resonance imaging reveals differences between activation of the central auditory system in the young and old brain. Altogether, the information reviewed in this article speaks in favor of specific age-related changes in the central auditory system that occur mostly independently of the changes in the inner ear and that form the basis of the central presbycusis.
衰老伴随着听力衰退，这使得我们理解言语变得复杂，尤其是在嘈杂环境中。这种听力缺陷部分是由毛细胞丧失以及血管纹功能障碍引起的。然而，听觉系统的中枢部分也会受到衰老相关过程的影响，这些过程可能独立于影响外周感受器的过程。在此，我们综述衰老过程中听觉系统中枢部分发生的主要变化。大多数关于实验动物听觉系统中枢与年龄相关变化的信息来自于使用免疫细胞化学针对谷氨酸脱羧酶、小白蛋白、钙结合蛋白和钙视网膜蛋白变化的实验。这些数据还伴有关于神经元数量与年龄相关变化以及实验动物行为变化的信息。衰老原则上伴随着灰质和白质萎缩，导致脑脊液间隙增大。磁共振波谱显示，人类听觉皮层不仅会萎缩，老年大脑中某些代谢物的含量也会发生变化。除此之外，功能磁共振成像揭示了年轻和老年大脑中听觉系统中枢激活的差异。总而言之，本文综述的信息表明，听觉系统中枢存在特定的与年龄相关的变化，这些变化大多独立于内耳变化，是中枢性老年聋的基础。
