Neural development of lexical processing

描述（由申请人提供）：本项目的目标是使用功能性磁共振成像（fMRI）检查正常儿童（7-15奥尔兹）词汇处理神经基质的发育和个体差异。我们建议检查这些差异与词汇任务，旨在挖掘到模态内处理（听觉押韵和视觉拼写任务），转换正字法和音韵之间的跨模态处理（听觉拼写和视觉押韵任务）和模态词理解（听觉和视觉意义任务）。这项建议有三个具体目标。首先，我们将使用一个横向和纵向的设计相结合，以衡量在较短的时间内在广泛的年龄范围内词汇加工的发展变化。我们预计，发展将产生增加激活的单峰地区一致的输入方式和减少激活后异模区。其次，我们将研究大脑激活和技能的个体差异之间的相关性是否取决于发展水平。我们预计，行为将相关的认知组件所需的词汇任务的年龄较大的儿童，但将弱相关的后异模态激活的年龄较小的儿童。第三，我们将研究听觉和视觉输入方式之间以及拼写、押韵和意义任务之间激活重叠的发展差异。我们预计，年龄较小的儿童将显示更多的重叠激活比年龄较大的儿童之间的道德和任务。这些具体的目标还包括参数操作和一个简单与复杂的基线为每个词汇任务，使我们可以更清楚地将激活过程中的差异，无论是在词汇处理的发展或技能的差异。由于很少有功能磁共振成像研究直接检查词汇加工的发展或个体差异，这个项目的正常人群将有影响，未来的研究阅读和语言障碍的神经基础上的儿童。

DESCRIPTION (provided by applicant): The goal of this project is to examine developmental and individual differences in the neural substrate for lexical processing in normal children (7-15 year olds) using fMRI (functional magnetic resonance imaging). We propose to examine these differences with lexical tasks designed to tap into intra-modal processing (auditory rhyming and visual spelling tasks), conversion between orthography and phonology during crossmodal processing (auditory spelling and visual rhyming tasks) and modal word comprehension (auditory and visual meaning tasks). This proposal has three specific aims. First, we will use a combination of a cross-sectional and longitudinal design in order to measure developmental changes in lexical processing across a wide age range in a relatively short amount of time. We expect that development will produce increased activation in unimodal areas consistent with the modality of input and decreased activation in posterior heteromodal areas. Second, we will examine whether the correlation between brain activation and individual differences in skill depends on developmental level. We expect that behavior will correlate with the cognitive components required by the lexical task for older children, but will weakly correlate with posterior heteromodal activation for younger children. Third, we will examine developmental differences in the overlap in activation between auditory and visual modalities of input and between the spelling, rhyming and meaning tasks. We expect that younger children will show more overlap in activation than older children between moralities and between tasks. These specific aims also incorporate parametric manipulations and a simple versus complex baseline for each lexical task, so that we can more clearly relate differences in activation during tasks to either developmental or skill differences in lexical processing. Because few fMRI studies have directly examined developmental or individual differences in lexical processing, this project on a normative population will have implications for future studies on the neural basis of reading and language impairments in children.