PNAS：噪音影响婴幼儿听力和智力发育
近期出版的美国《国家科学院院刊》（PNAS）刊登了华东师范大学生命科学学院听觉神经生物学实验室周晓明教授和美国加州大学Merzenich MM教授合作的最新研究成果——早期间断噪声对听皮层处理声音时间性信息的持久影响的研究论文。
早期不良环境对婴幼儿听觉系统的发育有什么影响？这种影响和他们语言、智力的发育有什么关系？华东师范大学周晓明教授作为共同通讯作者和美国加州大学Merzenich MM教授日前在美国《国家科学院院刊》发表的研究论文或许有助于回答这些问题。在题为《早期间断噪声对听皮层处理声音时间性信息的持久影响》的研究论文中，作者发现出生后“关键期”中等强度的间断噪声暴露会严重影响大鼠听皮层神经元对连续声刺激的跟随能力。和正常动物相比，这些动物对不同间隔的连续声刺激的反应强度、调谐特性及反应同步性均有明显下降。这种影响在结束噪声暴露后一直持续到成年。自然界的声音，包括动物的发声和人类的语言，均包含有特定的时间性信息。要精确感知这些声音依赖于大脑对其包含的时间性信息的及时处理和整合。对婴幼儿而言，听觉系统对连续声跟随能力的损伤不仅影响到他们对声音的感知，还会造成他们语言理解能力的缺陷，并进而影响到智力发育。鉴于听皮层在听觉系统对声音时间性信息的处理和整合过程中起关键性的作用，该项研究提示早期不良声音环境造成的不仅仅是成年后听力的损伤，或许还会造成语言理解能力和智力的缺陷。作为该项研究的延伸，作者目前正试图使用知觉学习等强化训练措施，来矫正早期不良声音环境引起的听觉系统对声音时间性信息处理能力的损伤。这可能为那些听觉障碍、语言表达困难和理解能力缺陷的患者带来福音。（来源：华东师范大学）
生物谷推荐原始出处：
（PNAS），10.1073/pnas.0800009105，Xiaoming Zhou，Michael M. Merzenich
Enduring effects of early structured noise exposure on temporal modulation in the primary auditory cortex
Xiaoming Zhou*,
,
and Michael M. Merzenich*,
*Department of Otolaryngology, W. M. Keck Center for Integrative Neuroscience, and Coleman Laboratory, University of California, San Francisco, CA 94143; and College of Life Sciences, East China Normal University, Shanghai 200062, China
Contributed by Michael M. Merzenich, January 2, 2008 (received for review November 15, 2007)
Studies have shown that acoustic experiences significantly contribute to the functional shaping of the structural organization and signal processing capacities of the mammalian auditory system during postnatal development. Here, we show how an early epoch of exposure to structured noise influences temporal processing in the rat primary auditory cortex documented immediately after exposure and again in adulthood. Pups were continuously exposed to broadband-pulsed noise across the critical period for auditory system development. Immediately after cessation of exposure at postnatal day 
35 (P35) or 55 days later (i.e., P90) in other rats, the temporal modulation-transfer functions of cortical neurons were documented. We found that pulsed noise exposure at a low modulation rate significantly decreased cortical responses to repetitive stimuli presented across a range of higher modulation rates. The highest temporal rate at which temporal modulation-transfer function was at half of its maximum was reduced when compared with naïve rats. Low-rate pulsed noise exposure also decreased cortical response synchronization at higher stimulus rates, as shown by vector strength and Rayleigh statistic measures. These postexposure changes endured into adulthood. These findings bear significant implications for the role of early sound experiences as contributors to the ontogeny of human auditory and language-related abilities and impairments.
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