National Institute for Health and Medical Research (INSERM), U1051, Plasticity of the Central Nervous System, Human Stem Cells and Glial Tumors, Institute for Neurosciences of Montpellier, Montpellier University Medical Center, 80 Av Augustin Fliche, 34091 Montpellier, France.
Neuropsychologia. 2013 Aug;51(10):1814-22. doi: 10.1016/j.neuropsychologia.2013.06.007. Epub 2013 Jun 15.
Accessing the meaning of words, objects, people and facts is a human ability, made possible thanks to semantic processing. Although studies concerning its cortical organization are proficient, the subcortical connectivity underlying this semantic network received less attention. We used intraoperative direct electrostimulation, which mimics a transient virtual lesion during brain surgery for glioma in eight awaken patients, to map the anatomical white matter substrate subserving the semantic system. Patients performed a picture naming task and a non-verbal semantic association test during the electrical mapping. Direct electrostimulation of the inferior fronto-occipital fascicle, a poorly known ventral association pathway which runs throughout the brain, induced in all cases semantic disturbances. These transient disorders were highly reproducible, and concerned verbal as well as non-verbal output. Our results highlight for the first time the essential role of the left inferior fronto-occipital fascicle in multimodal (and not only in verbal) semantic processing. On the basis of these original findings, and in the lights of phylogenetic considerations regarding this fascicle, we suggest its possible implication in the monitoring of the human level of consciousness related to semantic memory, namely noetic consciousness.
理解单词、物体、人和事实的含义是人类的一种能力，这得益于语义处理。尽管关于其皮质组织的研究已经很成熟，但语义网络的皮质下连接却没有得到太多关注。我们使用术中直接电刺激，在 8 名清醒患者进行脑胶质瘤手术时模拟短暂的虚拟损伤，来绘制语义系统的解剖性白质基础。患者在电刺激映射过程中进行图片命名任务和非语言语义联想测试。直接电刺激下额枕束，这是一种贯穿大脑的、不太为人知的腹侧连接通路，在所有情况下都引起了语义障碍。这些短暂的障碍具有高度可重复性，既涉及言语输出，也涉及非言语输出。我们的结果首次强调了左侧下额枕束在多模态（不仅是言语）语义处理中的重要作用。基于这些原始发现，并根据对这条束的系统发生学考虑，我们提出它可能与与语义记忆相关的人类意识水平的监测有关，即理智意识。
