Di Caro Valeria, Cesari Paola, Sala Francesco, Cattaneo Luigi
Section of Neurosurgery, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona 37134, Italy.
Section of Movement Sciences, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona 37134, Italy.
Proc Natl Acad Sci U S A. 2025 Mar 11;122(10):e2419801122. doi: 10.1073/pnas.2419801122. Epub 2025 Mar 5.
Visually guided grasping is a fundamental building block of animal behavior, the specific neural mechanisms of which remain poorly documented in the human brain. We have mapped the causal contribution of different brain parts to grasping behavior by studying the kinematic parameters of 33 patients with brain tumors, engaged in actions directed toward objects of different sizes. Using motion capture techniques, we analyzed the dynamics of grip aperture and wrist transport. Voxel-based lesion-symptom mapping analysis was applied to correlate lesion volumes with specific behavioral deficits. Results showed that lesions in the anterior and lateral bank of the intraparietal sulcus produced impaired finger scaling related to object size. Conversely, impaired velocity of finger aperture was associated with lesions in the dorsal premotor cortex (PMd). Grip aperture deficits following dominant hemisphere lesions were bilateral and were unilateral when following nondominant hemisphere lesions. Impaired wrist transport during reaching was associated with lesions in the first segment of the superior longitudinal fasciculus. Our work highlights an architecture of the grasping network in humans, with unique species-specific features. We hypothesize a model of human neural architecture in which object geometry for hand preshaping is first coded in the left anterior intraparietal cortex and then shared with the right hemisphere. Execution of the motor program of hand preshaping is then performed by the PMd on the corresponding side.
视觉引导抓握是动物行为的一个基本组成部分，其具体的神经机制在人类大脑中仍鲜有记载。我们通过研究33名脑肿瘤患者针对不同大小物体的抓握行为运动学参数，绘制了不同脑区对抓握行为的因果贡献图。利用动作捕捉技术，我们分析了抓握孔径和手腕移动的动力学。基于体素的损伤-症状映射分析被用于将损伤体积与特定行为缺陷相关联。结果显示，顶内沟前后壁的损伤导致与物体大小相关的手指缩放受损。相反，手指孔径速度受损与背侧运动前皮层（PMd）的损伤有关。优势半球损伤后的抓握孔径缺陷是双侧的，而非优势半球损伤后的缺陷是单侧的。伸手过程中手腕移动受损与上纵束第一段的损伤有关。我们的研究突出了人类抓握网络的架构，具有独特的物种特异性特征。我们提出了一个人类神经架构模型，其中手部预塑形的物体几何形状首先在左前顶内皮层编码，然后与右半球共享。手部预塑形运动程序的执行随后由相应一侧的PMd完成。
