Imaging Studies of Normal and Impaired Lexical Retrieval

描述（由申请人提供）：对正常受试者和神经系统患者的研究表明，左下颞叶皮层和极颞叶皮层的完整性对正常的词汇-语义过程至关重要，这些过程的解剖学基础部分被概念类别分开。我们将通过两种经验效应（语义干扰和词频效应）来探讨这些区域在词汇加工中的作用，这两种效应分别来自词汇选择和语音编码激活的不同需求。通过功能性磁共振成像（fMRI）测量这些效应的生理相关性，将阐明左外颞叶在正常词汇加工中的作用，并澄清是否专门参与词汇加工的神经区域是按概念类别分开的。最后，我们将利用一个独特的病人登记包括受试者获得性左颞叶损伤和失范。我们将使用功能磁共振成像技术来检查这些受试者的语义干扰和词频效应的相关性，该技术分离出成功命名试验的相关性。研究结果将阐明优选神经系统损伤后残余词汇检索的神经基础。这里进行的研究涉及更广泛的可塑性、恢复以及与语言和记忆相关的系统的相互作用问题，并将促进功能磁共振成像技术在语言障碍患者中的适应，在这些患者中，它可能被用于跟踪疾病和恢复的过程，以及对治疗的反应。

DESCRIPTION (provided by applicant): Studies of normal subjects and neurological patients show that the integrity of the left inferior and polar temporal cortex is critical to normal lexical-semantic processes, and that the anatomic substrates of these processes are partially segregated by conceptual category. We will probe the role of these regions in lexical processing using two empirical effects (the semantic interference and word frequency effects) that arise from differential demands on lexical selection and phonological code activation, respectively. The physiologic correlates of these effects, measured with functional magnetic resonance imaging (fMRI), will illuminate the role of the left extrasylvian temporal lobe in normal lexical processing, and clarify whether neural regions specifically involved in lexical processing are segregated by conceptual category. Finally, we will take advantage of a unique Patient Registry including subjects with acquired left temporal lobe damage and anomia. We will examine the correlates of the semantic interference and word frequency effects in these subjects using fMRI techniques that isolate the correlates of successful naming trials. The results will clarify the neural basis for residual lexical retrieval after damage to preferred neural systems. The studies undertaken here address wider issues of plasticity, recovery, and the interplay of systems related to language and memory, and will promote adaptation of fMRI imaging technology to language-impaired patients, in whom it may be used to track the course of disease and recovery, as well as responses to treatment.