Early Development of Auditory Temporal Processing

描述（由申请人提供）：本研究将使用适当的 动物模型，以确定行为，生理和细胞变化， 与听觉时间处理缺陷有关我们将测试 假设一种早期损伤（暴露于低水平铅）， 而不是另一个（暴露于响亮的声音）导致听力迅速变化的缺陷 在声音方面。文献中的四项观察结果预测，铅毒性是一种 合理的操作，以调查听觉时间加工缺陷。 首先，铅中毒会导致阅读障碍。第二，患有阅读障碍的儿童 听觉时间和语音处理缺陷。第三，提前曝光 这些动物体内低水平的铅会导致听觉时间处理 disorder.第四，人类和这些动物听力的发展是 在许多方面，包括听觉时间处理，都是非常相似的。 受试者脑电中无条件延迟的信号检测分析 发声将量化向前，向后， 同时掩蔽、辨别言语和类言语刺激 包含声音和音调起始时间线索。几个非时间控件 （绝对阈值、频率和强度鉴别）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确定 行为缺陷的可能机制。根据一个重要 当前假设，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不足。 关于听觉时间处理的早期发展的基本问题， 这些重要的能力受到的伤害仍然存在 无人回应这些基本信息将帮助我们了解 常见的环境侮辱，也许是语音的病因 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.