DEVELOPMENT OF CEREBRAL SPECIALIZATIONS

描述：(改编自《调查员摘要》)：总体目标 是为了刻画人类发展中依赖经验的变化 并检验它们是由多个， 特定的关键时期。调查人员将描述这些影响的特征 听觉剥夺对视觉系统的功能组织的影响， 以及视觉-手册语言(美国手语)习得的效果 Language，ASL)以及延迟接触语言对 大脑不同语言系统的功能组织。这个 调查人员将测试不同的身份概念和 常态研究中视觉和语言中的子系统组织 听到成年人的声音。他们将确定影响的性质和时间 当改变的经历影响到这些人的正常发展时 系统在研究先天和后来的聋人，以及在 美国手语和英语的本地和后期学习者。调查人员将记录 事件相关脑电位(ERPS)与血氧变化 使用功能磁共振成像(FMRI)的级别 描述神经激活的时间和位置如下 受试组执行旨在激活特定方面的任务 感觉和语言功能。他们将评估这一假说，该假说由 我们之前的行为、事件相关电位和功能磁共振研究表明，有相当大的 视觉系统和视觉系统改变的功能特异性 听觉剥夺后可能发生的语言系统，以及：1. 先天失聪的受试者更准确，显示速度更快， 在检测时，比正常听力SS更广泛的神经激活， 定位和处理视觉远边缘的视觉事件 调节这一过程的神经系统更多 在聋人SS中广泛存在，并包括处理听觉信息的区域 正常听力；3.语言中有几个不同的子系统 它们在依赖和修改的程度上有所不同 由语言经验决定；4.内部神经系统存在重叠 左半球负责处理ASL和英语，但也有 广泛激活右侧的颞区和顶区 仅用于处理ASL的半球。由于这些研究将确定 在人类发展的多个不同时期，当特定的投入 从环境方面产生的影响最大，其结果将会带来 对特定教育计划的时间段的影响 优化听力和聋儿的发展。

DESCRIPTION: (Adapted From The Investigator's Abstract): The broad goals are to characterize experience-dependent changes in the developing human brain and to test the hypothesis that they are determined by multiple, specific critical periods. The investigators will characterize the effects of auditory deprivation on the functional organization of the visual system, and the effects of acquisition of a visual-manual language (American Sign Language, ASL) and the effects of delayed exposure to language on the functional organization of different language systems of the brain. The investigators will test different conceptions of the identity and organization of subsystems within vision and language in studies of normal hearing adults. They will determine the nature of the effects and the time periods when altered experience affects the normal development of these systems in studies of congenitally and later deafened individuals, and in native and late leamers of ASL and English. The investigators will record event-related brain potentials (ERPS) and changes in blood oxygenation levels employing functional magnetic resonance imaging (FMRI) to characterize the timing and the location of neural activation as these groups of subjects perform tasks designed to activate specific aspects of sensory and language functions. They will assess the hypothesis, raised by our previous behavioral, ERP and FMRI studies, that there is considerable functional specificity in the alterations in the visual system and the language systems that can occur following auditory deprivation and that: 1. congenitally deaf subjects are more accurate and display faster and more extensive neural activation than normal hearing Ss when detecting, localizing and attending to visual events in the far periphery of the visual fields; 2. the neural systems that mediate this processing are more extensive in deaf Ss and include areas that process auditory information in normal hearing Ss; 3. there are several distinct subsystems within language and these differ in the degree to which they are dependent on and modified by language experience; 4. there is overlap in the neural systems within the left hemisphere that process ASL and English, but there is also extensive activation of the temporal and parietal regions of the right hemisphere for processing ASL only. Since these studies will determine the multiple, different time periods in human development when specific inputs from the environment have the greatest impact, the results will carry implications for the time periods when specific educational programs would optimize development in hearing and deaf children.