Department of Pediatrics, Detroit Medical Center, Children's Hospital of Michigan, Wayne State University, Detroit, Michigan.
Department of Neurological Surgery, Wakayama Medical University, Wakayama-shi, Japan.
Epilepsia. 2019 Feb;60(2):255-267. doi: 10.1111/epi.14648. Epub 2019 Feb 1.
The strength of presurgical language mapping using electrocorticography (ECoG) is its outstanding signal fidelity and temporal resolution, but the weakness includes limited spatial sampling at an individual patient level. By averaging naming-related high-gamma activity at nonepileptic regions across a large number of patients, we provided the functional cortical atlases animating the neural dynamics supporting visual-object and auditory-description naming at the whole brain level.
We studied 79 patients who underwent extraoperative ECoG recording as epilepsy presurgical evaluation, and generated time-frequency plots and animation videos delineating the dynamics of naming-related high-gamma activity at 70-110 Hz.
Naming task performance elicited high-gamma augmentation in domain-specific lower-order sensory areas and inferior-precentral gyri immediately after stimulus onset. High-gamma augmentation subsequently involved widespread neocortical networks with left hemisphere dominance. Left posterior temporal high-gamma augmentation at several hundred milliseconds before response onset exhibited a double dissociation; picture naming elicited high-gamma augmentation preferentially in regions medial to the inferior-temporal gyrus, whereas auditory naming elicited high-gamma augmentation more laterally. The left lateral prefrontal regions including Broca's area initially exhibited high-gamma suppression subsequently followed by high-gamma augmentation at several hundred milliseconds before response onset during both naming tasks. Early high-gamma suppression within Broca's area was more intense during picture compared to auditory naming. Subsequent lateral-prefrontal high-gamma augmentation was more intense during auditory compared to picture naming.
This study revealed contrasting characteristics in the spatiotemporal dynamics of naming-related neural modulations between tasks. The dynamic atlases of visual and auditory language might be useful for planning of epilepsy surgery. Differential neural activation well explains some of the previously reported observations of domain-specific language impairments following resective epilepsy surgery. Video materials might be beneficial for the education of lay people about how the brain functions differentially during visual and auditory naming.
使用皮质电图 (ECoG) 进行术前语言定位的优势在于其出色的信号保真度和时间分辨率，但缺点是在个体患者水平上的空间采样有限。通过对大量患者的无癫痫区域的命名相关高伽马活动进行平均，可以在全脑水平上提供激活神经动力学的功能皮质图谱，以支持视觉物体和听觉描述命名。
我们研究了 79 名接受手术室外 ECoG 记录的患者，作为癫痫术前评估，生成时频图和动画视频，描绘了 70-110 Hz 命名相关高伽马活动的动力学。
命名任务表现引起特定于域的较低阶感觉区域和下中央前回的高伽马增强，在刺激开始后立即发生。高伽马增强随后涉及广泛的新皮层网络，以左侧半球为主导。在反应开始前几百毫秒，左后颞叶高伽马增强表现出双重分离；图片命名优先在颞下回内侧的区域引起高伽马增强，而听觉命名则在更外侧引起高伽马增强。包括 Broca 区在内的左侧外侧前额叶区域在反应开始前几百毫秒表现出高伽马抑制，随后在两种命名任务中都表现出高伽马增强。在图片命名中，与听觉命名相比，Broca 区的早期高伽马抑制更为强烈。随后的外侧前额叶高伽马增强在听觉命名中比在图片命名中更为强烈。
这项研究揭示了两种命名任务之间命名相关神经调节的时空动力学的对比特征。视觉和听觉语言的动态图谱可能对癫痫手术的规划有用。神经激活的差异很好地解释了一些之前报道的关于切除性癫痫手术后特定于领域的语言障碍的观察结果。视频材料可能有助于向非专业人士普及大脑在视觉和听觉命名过程中的差异功能。
