In the dual-stream model of language processing, the exact connectivity of the ventral stream to the anterior temporal lobe remains elusive. To investigate the connectivity between the inferior frontal gyrus (IFG) and the lateral part of the temporal and parietal lobes, we integrated spatiotemporal profiles of cortico-cortical evoked potentials (CCEPs) recorded intraoperatively in 14 patients who had undergone surgical resection for a brain tumor or epileptic focus. Four-dimensional visualization of the combined CCEP data showed that the pars opercularis (Broca’s area) is connected to the posterior temporal cortices and the supramarginal gyrus, whereas the pars orbitalis is connected to the anterior lateral temporal cortices and angular gyrus. Quantitative topographical analysis of CCEP connectivity confirmed an anterior–posterior gradient of connectivity from IFG stimulus sites to the temporal response sites. Reciprocality analysis indicated that the anterior part of the IFG is bidirectionally connected to the temporal or parietal area. This study shows that each IFG subdivision has different connectivity to the temporal lobe with an anterior–posterior gradient and supports the classical connectivity concept of Dejerine; that is, the frontal lobe is connected to the temporal lobe through the arcuate fasciculus and also a double fan-shaped structure anchored at the limen insulae.

中文翻译：

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人类左额下回的连接梯度：术中皮质-皮质诱发电位研究。

在语言处理的双流模型中，腹侧流与前颞叶的确切连接仍然难以捉摸。为了研究额下回 (IFG) 与颞叶和顶叶外侧部分之间的连接性，我们整合了 14 名因脑肿瘤接受手术切除术的患者术中记录的皮质-皮质诱发电位 (CCEP) 的时空分布图或癫痫病灶。组合 CCEP 数据的四维可视化显示，岛盖部（布罗卡区）与后颞叶皮质和缘上回相连，而眶部与前外侧颞叶皮质和角回相连。CCEP 连接的定量拓扑分析证实了从 IFG 刺激部位到时间反应部位的连接的前后梯度。互惠分析表明，IFG 的前部与颞叶或顶叶区域双向连接。本研究表明，每个 IFG 细分与颞叶的连接具有前后梯度，并支持 Dejerine 的经典连接概念；也就是说，额叶通过弓状束与颞叶相连，也是一个锚定在岛叶上的双扇形结构。本研究表明，每个 IFG 细分与颞叶的连接具有前后梯度，并支持 Dejerine 的经典连接概念；也就是说，额叶通过弓状束与颞叶相连，也是一个锚定在岛叶上的双扇形结构。本研究表明，每个 IFG 细分与颞叶的连接具有前后梯度，并支持 Dejerine 的经典连接概念；也就是说，额叶通过弓状束与颞叶相连，也是一个锚定在岛叶上的双扇形结构。