fMRI and TMS Analysis of Cerebellar Cognitive Function

描述（由申请人提供）：本研究的总体目标是通过功能磁共振成像（fMRI）和经颅磁刺激（TMS）技术与言语工作记忆任务相结合，更好地了解小脑和脑小脑网络对认知功能的贡献。Sternberg言语工作记忆任务具有编码、维持和检索三个时间上不同的阶段，是研究脑-小脑对认知的贡献的理想模型系统。到目前为止，我们的研究已经支持了脑小脑言语工作记忆模型，该模型强调了新皮层发音控制区域（如布罗卡区）与上小脑之间的功能联系，以及连接位于下顶叶区域的语音存储新皮层底物与下小脑之间的第二个网络。我们建议在三个具体目标中进一步测试和扩展该模型。第一项研究将强调编码阶段，并将测试小脑上区和额叶后区参与独立于刺激方式的发音轨迹的初始准备的假设。第二个目标将强调维护阶段。我们将测试右下小脑在功能上与左下顶叶区相连的假设，当语音存储需求被系统地操纵时，这些区域的激活将被串联调节。此外，我们将验证一种假设，即暂时性语音储存缺陷综合征，类似于在左颞顶叶病变患者中观察到的，可以在TMS实验室中通过刺激左顶叶下区和右小脑下区来重现。第三个目标将强调检索阶段。Sternberg任务的检索阶段需要使用存储的信息，在我们的事件相关调查中，引起的小脑激活最少。我们假设，通过增加任务的执行要求——通过施加额外的处理要求——我们将观察到与检索阶段相关的小脑激活的增加。我们进一步假设，经颅磁刺激在检索阶段产生的行为中断量将与检索阶段相关的小脑激活量相关。

DESCRIPTION (provided by applicant): The overall goal of this research is to better understand the contribution of the cerebellum and cerebrocerebellar networks to cognitive function by combining functional MRI (fMRI) and transcranial magnetic stimulation (TMS) techniques with tasks of verbal working memory. The Sternberg verbal working memory task, with three temporally distinct phases of encoding, maintenance, and retrieval, is an ideal model system for studying cerebro-cerebellar contributions to cognition. Our studies to date have supported a cerebrocerebellar verbal working memory model that emphasizes a functional link between neocortical articulatory control regions, such as Broca's Area, to the superior cerebellum, and a second network that links neocortical substrates of phonological storage, located in inferior parietal regions, to the inferior cerebellum. We propose to further test and extend this model in three specific aims. The first will emphasize the encoding phase and will test the hypothesis that the superior cerebellum and posterior frontal regions participate in the initial preparation of the articulatory trajectory independent of stimulus modality. The second aim will emphasize the maintenance phase. We will test the hypothesis that the right inferior cerebellum is functionally linked to the left inferior parietal region and that activation in these regions will be modulated in tandem when phonological storage demands are systematically manipulated. In addition, we will test the hypothesis that a transient phonological storage deficit syndrome, similar to that observed in left temporal-parietal lesioned patients, can be reproduced in the TMS lab using stimulation to left inferior parietal and right inferior cerebellar regions. The third aim will emphasize the retrieval phase. The retrieval phase of the Sternberg task, which requires utilization of the stored information, has elicited the least amount of cerebellar activation in our event-related investigations. We hypothesize that by increasing the executive demands of the task - by imposing additional processing requirements - we will observe increases in retrieval-phase-related cerebellar activation. We further hypothesize that the amount of behavioral disruption produced by TMS in the retrieval phase will be correlated with the amount of retrieval-phase related cerebellar activation.