Cortical-Basal Ganglia Speech Networks

项目总结 这些活动并不完全由皮质突起调节，而是依赖于基底节内的交流。 丘脑皮质环路。言语就是一个例子，尽管基底节是如何独特地参与这一过程的 由于缺乏经验数据，人类的行为尚不清楚。例如，领先的计算模型 言语产生忽略了通往丘脑底核(STN)的超直接皮质通路，下丘脑是一种基底神经节 涉及与语音产生相关的多个认知过程(例如动作)的节点 选择和抑制、行为切换、增益调制、运动学习)。认识到这一深度 脑刺激(DBS)手术提供了直接测量人类神经活动的唯一机会 基底节，我们开始研究运动和语言语音信息是如何编码的 在STN-感觉运动皮质网络内。我们建立了一个新的实验范式，其中 皮层脑电(ECoG)与STN单单位活动和局部场电位同步记录 (LFP)，在DBS手术中，患者处于清醒和说话状态。我们发现STN神经元的活动是 言语产生过程中的动态，表现出行为选择性的抑制和刺激 成群的神经元。在种群水平上，我们发现STN的活动以特定的发音跟踪 运动特征和关节运动中的增益调整。此外，我们的数据表明， 在语音计划中STN，因为STN活动似乎在语音开始之前被调制。这些发现 使我们扩大了ECoG覆盖范围，以额外记录涉及语音感知的区域(卓越 颞叶回)和计划(额叶下回)。给出了非人类灵长类动物的证据 听觉基底节-丘脑皮质环和已知的额叶广泛区域的超直接投射 皮层到STN，我们从言语感知和言语规划两个方面提出了超定向通路 皮质区域投射到STN，参与语言控制。支持这一想法，我们记录了 刺激STN后的诱发电位不仅与逆行激活相一致 感觉运动皮质，但也来自额下回(IFG)和颞上回(STG)。我们的 主要假设是STN和功能不同的皮质区域之间的相互作用有助于 语言的多个方面，在感知、规划和调制的层面上。目标1使用刺激 和功能连通性测量，以映射皮质-STN语音网络。目标2，并行，探测器 拟议的基底节功能与语音相关，通过同时记录神经活动和语音 利用朗伯德效应选择性干扰语音的听觉重复任务中的声学 制作。所产生的数据将通知对当前语音产生模型的修改，这 随后将在目标3中用线索和反应锁定的术中刺激进行测试。

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.