Cortical-Basal Ganglia Speech Networks

项目摘要 动作并不仅仅是由皮层过程介导的，而是依赖于基底神经节内的交流- 丘脑皮质环言语就是一个例子，尽管基底神经节如何独特地参与其中 由于缺乏经验数据，人类行为并不清楚。例如， 言语产生忽略了到丘脑底核（一个基底神经节）的超直接皮层通路 涉及与言语产生相关的多个认知过程（例如动作）的节点 选择和抑制、行为转换、增益调制、运动学习）。认识到， 脑刺激（DBS）手术提供了直接测量人类神经活动的唯一机会 基底神经节，我们开始研究，以了解如何运动和语言的语音信息编码 在STN-感觉运动皮层网络中。我们建立了一个新的实验范式， 同时记录皮层电图（ECoG），记录皮层单个单位活动和局部场电位 (LFP)在DBS手术期间，患者清醒并说话。我们发现神经元的活动 在言语产生过程中是动态的，表现出行为选择性抑制和单独的兴奋， 神经元群体。在群体水平上，我们发现， 运动功能和发音运动中的增益调节。此外，我们的数据表明， 在言语计划中，言语活动似乎在言语开始之前被调制。这些发现 使我们扩大了ECoG覆盖范围，以额外记录涉及言语感知（上级）区域 颞回）和计划（额下回）。鉴于非人灵长类动物中存在的 听觉基底神经节-丘脑皮质环和已知的额叶广泛区域的超直接投射 我们认为，从言语感知和言语规划的超直接通路 皮层的一些区域投射到大脑皮层，并对语言控制起作用。为了支持这一观点，我们记录了 刺激后的诱发电位与逆向激活一致，不仅在 感觉运动皮层，但也来自额下回（IFG）和上级颞回（STG）。我们 一个主要的假设是，大脑皮层和功能不同的皮层区域之间的相互作用有助于 语言的多个方面，在感知、计划和调节的层面上。Aim 1使用刺激 和功能连接性测量来映射皮层-皮层语音网络。目标2，并行，探测 通过同时记录神经活动和语音，提出了与语音相关的基底神经节功能， 在听觉重复任务中使用伦巴德效应选择性地干扰语音的声学 生产由此产生的数据将为修改当前的语音产生模型提供信息， 随后将在Aim 3中使用提示和响应锁定术中刺激进行测试。

PROJECT SUMMARY Actions are not mediated solely by cortical processes but rely on communication within basal ganglia- thalamocortical loops. Speech is one example, although how the basal ganglia participate in this uniquely human behavior is not clear, due to a lack of empirical data. For instance, the leading computational model of speech production ignores the hyperdirect cortical pathway to the subthalamic nucleus (STN), a basal ganglia node that has been implicated in multiple cognitive processes relevant to speech production (e.g. action selection and suppression, behavioral switching, gain modulation, motor learning). Recognizing that deep brain stimulation (DBS) surgery offers the only opportunity to directly measure neural activity in the human basal ganglia, we initiated studies to understand how motor and linguistic speech information is encoded within the STN-sensorimotor cortical network. We established a novel experimental paradigm, where electrocorticography (ECoG) is recorded simultaneously with STN single unit activity and local field potentials (LFP), during DBS surgery in which patients are awake and speaking. We discovered that STN neuron activity is dynamic during speech production, exhibiting behaviorally-selective inhibition and excitation of separate populations of neurons. At the population level, we found that STN activity tracks with specific articulatory motor features and with gain adjustment in articulatory movements. In addition, our data suggest a role for the STN in speech planning, in that STN activity appears to be modulated prior to speech onset. These findings led us to expand ECoG coverage to additionally record from areas involved in speech perception (superior temporal gyrus) and planning (inferior frontal gyrus). Given the evidence in nonhuman primates for an auditory basal ganglia-thalamocortical loop and the known hyperdirect projections from broad areas of frontal cortex to the STN, we propose that hyperdirect pathways from both speech perception and speech planning areas of cortex project to the STN and contribute to speech control. Supporting this idea, we have recorded evoked potentials after STN stimulation that are consistent with antidromic activation not only in sensorimotor cortex, but also from the inferior frontal gyrus (IFG) and superior temporal gyrus (STG). Our principal hypothesis is that interactions between the STN and functionally distinct cortical regions contribute to multiple aspects of speech, at the levels of perception, planning and modulation. Aim 1 uses stimulation and functional connectivity measures to map the cortical-STN speech network. Aim 2, in parallel, probes proposed basal ganglia functions relevant to speech, by simultaneously recording neural activity and speech acoustics during an auditory repetition tasks that employs the Lombard Effect to selectively perturb speech production. The resulting data will inform modifications to current models of speech production, which subsequently will be tested with cue and response-locked intraoperative stimulation in Aim 3.