Early Development of Auditory Temporal Processing

描述(由申请人提供)：这项研究将使用适当的 定义行为、生理和细胞变化的动物模型 与听觉时间处理的缺陷有关。我们将测试 假设一种类型的早期侮辱(接触低水平的铅) 而不是另一种(暴露在高声环境中)会导致听力快速变化的缺陷 在声音方面。文献中的四个观察结果预测，铅的毒性是一种 合理操作以研究听觉时间加工缺陷。 首先，铅中毒会导致阅读障碍。第二，阅读障碍的儿童有 听觉、时间和语音加工缺陷。第三，早期暴露 这些动物体内的低水平铅会导致听觉的时间处理 无序。第四，人类和这些动物的听力发育是 在许多方面非常相似，包括听觉时间处理。 受试者无条件延迟的信号检测分析 发声将量化向前、向后和向后的早期发展 语音和类语音刺激的同时掩蔽、辨别 包含语音和音调开始时间提示。几个非时态控制 (绝对阈值、频率和强度歧视)将证明 缺陷是快速变化的声音所特有的。生理记录和 中枢听觉系统细胞的免疫组织化学将定义 行为缺陷的可能机制。根据一个重要的 当前的假设，难以处理语言的基本元素 (音素)是由于对快速变化的声音的感知能力不足。 关于听觉时间加工早期发展的几个基本问题 可能导致这些重要能力减退的侮辱仍然存在 无人接听。这些基本信息将帮助我们了解 常见的环境侮辱，也许是音韵学的病因 处理缺陷(与儿童阅读障碍有关)，影响 5%和17%的孩子。

DESCRIPTION (provided by applicant): This research will use an appropriate animal model to define the behavioral, physiological, and cellular changes that correlate with deficits in auditory temporal processing. We will test the hypothesis that one type of early insult (exposure to low levels of lead) but not another (exposure to loud sound) causes a deficit in hearing rapid changes in sound. Four observations from the literature predict that lead toxicity is a reasonable manipulation for investigating auditory temporal processing deficit. First, lead poisoning causes dyslexia. Second, children with dyslexia have auditory temporal and phonological processing deficits. Third, early exposure to low levels of lead in these animals causes an auditory temporal processing disorder. Fourth, the development of hearing in humans and these animals is remarkably parallel in many aspects, including auditory temporal processing. Signal detection analyses of unconditioned delays in the subjects' vocalizations will quantify the early development of forward, backward, and simultaneous masking, discrimination of speech and speech-like stimuli containing voice- and tone-onset-time cues. Several non-temporal controls (absolute thresholds, frequency and intensity discrimination) will prove the deficits are unique to rapidly changing sounds. Physiological recordings and immuno-histochemistry of cells of the central auditory system will define possible mechanisms of the behavioral deficits. According to an important current hypothesis, difficulty processing the basic elements of language (phonemes) is due to a deficit in the perception of rapidly changing sounds. Basic questions about the early development of auditory temporal processing and the insults that can cause a decrement in these important abilities remain unanswered. This basic information will help us understand the effects of common environmental insults and perhaps the etiology of phonological processing deficits (associated with dyslexia in children) that affect between 5 percent and 17 percent of our children.