UMR 1253, iBrain, Université de Tours, Inserm, 37000 Tours, France.
Department of Neurosurgery, CHRU de Tours, 37000 Tours, France.
Brain. 2024 Jun 3;147(6):2245-2257. doi: 10.1093/brain/awae021.
Advanced methods of imaging and mapping the healthy and lesioned brain have allowed for the identification of the cortical nodes and white matter tracts supporting the dual neurofunctional organization of language networks in a dorsal phonological and a ventral semantic stream. Much less understood are the anatomical correlates of the interaction between the two streams; one hypothesis being that of a subcortically mediated interaction, through crossed cortico-striato-thalamo-cortical and cortico-thalamo-cortical loops. In this regard, the pulvinar is the thalamic subdivision that has most regularly appeared as implicated in the processing of lexical retrieval. However, descriptions of its connections with temporal (language) areas remain scarce. Here we assess this pulvino-temporal connectivity using a combination of state-of-the-art techniques: white matter stimulation in awake surgery and postoperative diffusion MRI (n = 4), virtual dissection from the Human Connectome Project 3 and 7 T datasets (n = 172) and operative microscope-assisted post-mortem fibre dissection (n = 12). We demonstrate the presence of four fundamental fibre contingents: (i) the anterior component (Arnold's bundle proper) initially described by Arnold in the 19th century and destined to the anterior temporal lobe; (ii) the optic radiations-like component, which leaves the pulvinar accompanying the optical radiations and reaches the posterior basal temporal cortices; (iii) the lateral component, which crosses the temporal stem orthogonally and reaches the middle temporal gyrus; and (iv) the auditory radiations-like component, which leaves the pulvinar accompanying the auditory radiations to the superomedial aspect of the temporal operculum, just posteriorly to Heschl's gyrus. Each of those components might correspond to a different level of information processing involved in the lexical retrieval process of picture naming.
高级的成像和脑区定位方法使我们能够识别出健康和受损大脑中的皮质节点和白质束,这些节点和束支持语言网络的双重神经功能组织,分为背侧语音流和腹侧语义流。而两个流之间相互作用的解剖学关联则知之甚少;有一种假说认为,这种相互作用是通过皮质下介导的,通过交叉的皮质-纹状体-丘脑-皮质和皮质-丘脑-皮质回路来实现。在这方面,丘脑枕是最常被认为与词汇提取处理有关的丘脑细分区域。然而,关于其与颞叶(语言)区域的连接的描述仍然很少。在这里,我们使用最先进的技术组合来评估丘脑枕-颞叶连接:在清醒手术和术后弥散 MRI 中进行白质刺激(n = 4),来自 Human Connectome Project 3 和 7T 数据集的虚拟解剖(n = 172)和显微镜辅助的尸检纤维解剖(n = 12)。我们证明了存在四种基本纤维束:(i)前成分(Arnold 束本身),由 Arnold 在 19 世纪首次描述, destined to the anterior temporal lobe;(ii)类似于视辐射的成分,离开丘脑枕,伴随着视辐射,到达后基底颞叶皮质;(iii)外侧成分,穿过颞干正交,到达中颞叶;和(iv)类似于听觉辐射的成分,离开丘脑枕,伴随着听觉辐射,到达颞叶帽状切迹的superomedial 部分,就在 Heschl 回的后面。这些成分中的每一个都可能对应于词汇提取过程中图片命名所涉及的不同信息处理水平。