Dipartimento di Psicologia, Università di Milano Bicocca, Piazza dell'Ateneo Nuovo 1, Edificio U6, 20126 Milano, Italy.
Neuroimage. 2011 Apr 1;55(3):1306-13. doi: 10.1016/j.neuroimage.2011.01.005. Epub 2011 Jan 8.
The brain's plasticity in response to sensory deprivation and other perturbations is well established. While the functional properties of the reorganized areas are under vigorous investigation, the factors that constrain cortical reorganization remain poorly understood. One factor constraining such reorganization may be long-distance subcortical connectivity between relevant cortical regions-reorganization attempts to preserve the functionality of subcortical connections. Here we provide human neurophysiological evidence for the role of the subcortical connections in shaping cortical reorganization of the networks involved in object naming following perturbation of normal function. We used direct electrical stimulation (DES) during surgical removal of gliomas to identify the sites that are involved in naming different categories of objects. The sites that were selectively inhibited in naming either living or non-living objects were displaced relative to those observed with other subject populations, possibly reflecting cortical reorganization due to slowly evolving brain damage. Subcortical DES applied to the white matter underlying these regions also led to category-specific naming deficits. The existence of these subcortical fiber pathways was confirmed using diffusion tensor tractography. These results constitute the first neurophysiological evidence for the critical role of subcortical pathways as part of the neural circuits that are involved in object naming; they also highlight the importance of subcortical connectivity in shaping cortical reorganization following perturbations of normal function.
大脑对感觉剥夺和其他干扰的可塑性是众所周知的。虽然对重组区域的功能特性正在进行积极的研究，但限制皮质重组的因素仍知之甚少。限制这种重组的一个因素可能是相关皮质区域之间的长距离皮质下连接——重组试图保持皮质下连接的功能。在这里，我们提供了人类神经生理学证据，证明皮质下连接在塑造正常功能受到干扰后的物体命名网络的皮质重组中的作用。我们在切除神经胶质瘤的手术过程中使用直接电刺激 (DES) 来识别参与命名不同类别的物体的部位。在命名活体或非活体物体时选择性抑制的部位相对于在其他受试人群中观察到的部位发生了位移，这可能反映了由于缓慢发展的脑损伤导致的皮质重组。对这些区域下的白质进行皮质下 DES 刺激也会导致特定于类别的命名缺陷。使用弥散张量纤维束追踪术证实了这些皮质下纤维通路的存在。这些结果构成了皮质下通路作为参与物体命名的神经回路的一部分的关键作用的第一个神经生理学证据；它们还强调了皮质下连接在正常功能受到干扰后的皮质重组中的重要性。
