Exploring the expressive language function of the supplementary motor area

项目概要 该奖学金的目标是提供心理语言学、功能学等方面的优秀多学科培训 通过发展对表达的机械理解来研究神经解剖学和颅内神经生理学 内侧额壁多个区域的语言功能，特别是辅助运动区 (SMA) 和 preSMA。这些区域的功能障碍与各种运动和语言缺陷有关 包括运动启动和排序、发音、句子规划以及言语等问题 包括发育性口吃在内的疾病。 SMA 已在非发声方面进行了研究 人类灵长类动物模型，但 preSMA 和 SMA 在语言产生中的功能作用只能是 在人类身上进行了探索。虽然内侧额壁有多个运动和言语关键皮层区域， 该提案假设 preSMA 和 SMA 在言语/语言和运动方面具有独特的作用 生产，前者涉及行动的选择，后者涉及行动的顺序。根据假设， PreSMA 参与语言和运动功能中元素和序列的选择，而 SMA 言语和运动程序的排序（例如发音）。虽然这些区域与不同的区域相互作用 皮质下和皮质区域、序列与选择是区分激活的关键变量 这些区域负责语言和运动任务。至关重要的是，我们假设相同的区域表现 运动和语言任务中的选择（preSMA）和排序（SMA）。为了回答这个问题，我们将 在慢性植入性癫痫患者 (N=20) 中使用立体脑电图 (SEEG) 颅内记录 结合神经心理学测试和功能性 MRI。在目标 1 中，我们将研究以下关系： 运动和语言任务中的排序与选择（重复与手指敲击序列的生成） 和音节）到 preSMA 和 SMA 中的宽带伽玛活动。我们假设 preSMA 和 SMA 将在运动和语言任务的选择（生成）条件下被激活，同时排序 （重复）仅激活 SMA 的任务。然后我们将研究 preSMA/SMA 与 了解与语言相关的信息如何传输到该区域以实现语音目的 生产。在目标 2 中，我们将首先使用 SEEG 皮质-皮质诱发电位来显示直接有效 preSMA/SMA 和语言区域之间的连接，包括言语运动皮层（输出）、下 额回（语音选择）和颞中回（语义选择）。然后我们将使用 SEEG 功能连接性表明，与语言区域的功能连接性在 语言任务与运动任务的比较。这里提出的跨学科方法将把 preSMA/SMA 的功能神经解剖学到表达语言的心理语言学分析。翻译成 临床实践中，我们的结果将更好地理解包括口吃在内的言语障碍，改善 功能性大脑图谱，并阐明 SMA 综合征语言功能障碍的机制。

Project Summary The goal of this fellowship is to provide excellent multidisciplinary training in psycholinguistics, functional neuroanatomy, and intracranial neurophysiology by developing mechanistic understanding of expressive language function in the multiple regions in the medial frontal wall, specifically the supplementary motor area (SMA) and preSMA. Dysfunction in these regions has been tied to a variety of motor and language deficits including issues with motor initiation and sequencing, articulation, and sentence planning as well as speech disorders including developmental stuttering. The SMA has been studied with respect to vocalization in non- human primate models, but the functional role of the preSMA and SMA in language production can only be explored in humans. While there are multiple motor and speech-critical cortical areas in the medial frontal wall, this proposal hypothesizes that the preSMA and SMA have unique roles in both speech/language and motor production, with the former involved in selection of action and the latter in sequencing of action. By hypothesis, PreSMA is involved in selection of elements and sequences in language and motor functions, while SMA sequencing of speech and motor programs (e.g. articulation). While these regions interact with different subcortical and cortical regions, sequence vs. selection is a critical variable that distinguishes activation in these regions in both language and motor tasks. Critically, we hypothesize that the same regions perform selection (preSMA) and sequencing (SMA) in motor and language tasks. To answer this question, we will utilize stereo EEG (SEEG) intracranial recording in chronically-implanted epilepsy patients (N=20) in conjunction with neuropsychological testing and functional MRI. In Aim 1, we will investigate the relationship of sequencing vs. selection in motor and language tasks (repetition vs. generation of sequences of finger taps and syllables) to broadband gamma activity in the preSMA and SMA. We hypothesize that preSMA and SMA will be activated in the selection (generation) condition for both motor and language tasks, while sequencing (repetition) tasks that will activate only SMA. We will then investigate the connectivity of the preSMA/SMA to understand how language-relevant information is transferred to this region for the purposes of speech production. In Aim 2, we will first use SEEG cortico-cortical evoked potentials to show direct effective connectivity between preSMA/SMA and language regions including speech motor cortex (output), inferior frontal gyrus (phonologic selection), and posterior middle temporal gyrus (semantic selection). We will then use SEEG functional connectivity to demonstrate that functional connectivity to language regions increases during language tasks in comparison to motor tasks. The cross-disciplinary approach proposed here will tie the functional neuroanatomy of preSMA/SMA to psycholinguistic analyses of expressive language. Translated into clinical practice, our results will create a better understanding of speech disorders including stuttering, improve functional brain mapping, and elucidate the mechanisms of language dysfunction in SMA syndrome.