Program in Neuroscience and Mental Health, Hospital for Sick Children Research Institute , Toronto, Ontario , Canada.
Institute of Biomaterials and Biomedical Engineering, University of Toronto , Toronto, Ontario , Canada.
J Neurophysiol. 2019 Jun 1;121(6):2020-2027. doi: 10.1152/jn.00079.2019. Epub 2019 Apr 10.
Resonant interactions between the thalamus and cortex subserve a critical role for maintenance of consciousness as well as cognitive functions. In states of abnormal thalamic inhibition, thalamocortical dysrhythmia (TCD) has been described. The characteristics of TCD include a slowing of resting oscillations, ectopic high-frequency activity, and increased cross-frequency coupling. Here, we demonstrate the presence of TCD in four patients who underwent resective epilepsy surgery with chronically implanted electrodes under anesthesia, continuously recording activity from brain regions at the periphery of the epileptogenic zone before and after resection. Following resection, we report an acceleration of the large-scale network resting frequency coincident with decreases in cross-frequency phase-amplitude coupling. Interregional functional connectivity in the surrounding cortex was also increased following resection of the epileptogenic focus. These findings provide evidence for the presence of TCD in focal epilepsy and highlight the importance of reciprocal thalamocortical oscillatory interactions in defining novel biomarkers for resective surgeries. Thalamocortical dysrhythmia (TCD) occurs in the context of thalamic dysfacilitation and is characterized by slowing of resting oscillations, ectopic high-frequency activity, and cross-frequency coupling. We provide evidence for TCD in focal epilepsy by studying electrophysiological changes occurring at the periphery of the resection margin. We report acceleration of resting activity coincident with decreased cross-frequency coupling and increased functional connectivity. The study of TCD in epilepsy has implications as a biomarker and therapeutic target.
丘脑和皮层之间的共振相互作用对意识的维持以及认知功能起着至关重要的作用。在丘脑抑制异常的情况下，已描述了丘脑皮层节律紊乱（TCD）。TCD 的特征包括静息振荡减慢、异位高频活动和跨频耦合增加。在这里，我们在四名接受了麻醉下切除性癫痫手术的患者中证明了 TCD 的存在，这些患者在切除前后通过慢性植入的电极连续记录了癫痫灶周围脑区的活动。切除后，我们报告了大尺度网络静息频率的加速，同时伴有跨频相位-幅度耦合的减少。切除致痫灶后，周围皮层的区域间功能连接也增加了。这些发现为局灶性癫痫中存在 TCD 提供了证据，并强调了丘脑皮层振荡相互作用在确定切除性手术的新型生物标志物方面的重要性。TCD 发生在丘脑失活的背景下，其特征是静息振荡减慢、异位高频活动和跨频耦合增加。我们通过研究切除边缘周围发生的电生理变化，为局灶性癫痫中的 TCD 提供了证据。我们报告了静息活动的加速与跨频耦合减少和功能连接增加同时发生。癫痫中 TCD 的研究具有作为生物标志物和治疗靶点的意义。
