Laboratorio de Neurociencias (LIM-27), Faculdade de Medicina, Departamento e Instituto de Psiquiatria, Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Rua Dr. Ovídio Pires de Campos, 785, SP, 05403-903, São Paulo, Brazil.
Faculdade de Letras, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.
Curr Neurol Neurosci Rep. 2021 Nov 24;21(12):73. doi: 10.1007/s11910-021-01156-5.
Subcortical structures have long been thought to play a role in language processing. Increasingly spirited debates on language studies, arising from as early as the nineteenth century, grew remarkably sophisticated as the years pass. In the context of non-thalamic aphasia, a few theoretical frameworks have been laid out. The disconnection hypothesis postulates that basal ganglia insults result in aphasia due to a rupture of connectivity between Broca and Wernicke's areas. A second viewpoint conjectures that the basal ganglia would more directly partake in language processing, and a third stream proclaims that aphasia would stem from cortical deafferentation. On the other hand, thalamic aphasia is more predominantly deemed as a resultant of diaschisis. This article reviews the above topics with recent findings on deep brain stimulation, neurophysiology, and aphasiology.
The more recent approach conceptualizes non-thalamic aphasias as the offspring of unpredictable cortical hypoperfusion. Regarding the thalamus, there is mounting evidence now pointing to leading contributions of the pulvinar/lateral posterior nucleus and the anterior/ventral anterior thalamus to language disturbances. While the former appears to relate to lexical-semantic indiscrimination, the latter seems to bring about a severe breakdown in word selection and/or spontaneous top-down lexical-semantic operations. The characterization of subcortical aphasias and the role of the basal ganglia and thalamus in language processing continues to pose a challenge. Neuroimaging studies have pointed a path forward, and we believe that more recent methods such as tractography and connectivity studies will significantly expand our knowledge in this particular area of aphasiology.
皮质下结构长期以来一直被认为在语言处理中起作用。自 19 世纪以来，语言研究中出现了越来越激烈的争论，随着时间的推移，这些争论变得越来越复杂。在非丘脑性失语症的背景下，已经提出了一些理论框架。断开假说假设，基底节损伤导致失语症是由于布罗卡区和韦尼克区之间的连接中断。第二种观点推测基底节会更直接地参与语言处理，第三种观点宣称失语症是由于皮质去传入。另一方面，丘脑性失语症更被认为是去传入的结果。本文综述了深部脑刺激、神经生理学和失语症学的最新发现对上述主题的研究。
最近的方法将非丘脑性失语症概念化为不可预测的皮质灌注不足的结果。关于丘脑，现在有越来越多的证据表明，丘脑的苍白球/外侧后核和前/腹前核对语言障碍有主要贡献。前者似乎与词汇语义辨别有关，而后者似乎导致单词选择和/或自发的自上而下的词汇语义操作严重中断。皮质下失语症的特征以及基底节和丘脑在语言处理中的作用仍然是一个挑战。神经影像学研究指出了前进的道路，我们相信，像示踪和连通性研究这样的较新方法将极大地扩展我们在这个特定的失语症领域的知识。
