Laboratory for Neuro- & Psychophysiology, Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium.
Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martino's Center for Biomedical Imaging, Charlestown, MA 02129, USA.
Cereb Cortex. 2018 Apr 1;28(4):1245-1259. doi: 10.1093/cercor/bhx037.
Prehension movements typically include a reaching phase, guiding the hand toward the object, and a grip phase, shaping the hand around it. The dominant view posits that these components rely upon largely independent parieto-frontal circuits: a dorso-medial circuit involved in reaching and a dorso-lateral circuit involved in grasping. However, mounting evidence suggests a more complex arrangement, with dorso-medial areas contributing to both reaching and grasping. To investigate the role of the dorso-medial reaching circuit in grasping, we trained monkeys to reach-and-grasp different objects in the dark and determined if hand configurations could be decoded from functional magnetic resonance imaging (MRI) responses obtained from the reaching and grasping circuits. Indicative of their established role in grasping, object-specific grasp decoding was found in anterior intraparietal (AIP) area, inferior parietal lobule area PFG and ventral premotor region F5 of the lateral grasping circuit, and primary motor cortex. Importantly, the medial reaching circuit also conveyed robust grasp-specific information, as evidenced by significant decoding in parietal reach regions (particular V6A) and dorsal premotor region F2. These data support the proposed role of dorso-medial "reach" regions in controlling aspects of grasping and demonstrate the value of complementing univariate with more sensitive multivariate analyses of functional MRI (fMRI) data in uncovering information coding in the brain.
抓握动作通常包括一个伸向目标的伸手阶段和一个握住目标的抓握阶段。主流观点认为，这些成分依赖于很大程度上独立的顶叶-额叶回路：一个参与伸手的背内侧回路和一个参与抓握的背外侧回路。然而，越来越多的证据表明，这种安排更为复杂，背内侧区域既参与伸手也参与抓握。为了研究背内侧伸手回路在抓握中的作用，我们训练猴子在黑暗中伸手抓握不同的物体，并确定手的形状是否可以从伸手和抓握回路的功能磁共振成像 (fMRI) 响应中解码出来。正如它们在抓握中所扮演的既定角色所示，在外侧抓握回路的前顶内 (AIP) 区域、下顶叶小叶区域 PFG 和腹侧运动前区 F5 以及初级运动皮层中发现了与物体特异性抓握解码相关的信息。重要的是，内侧伸手回路也传递了强大的抓握特异性信息，这表现在顶叶伸手区域（特别是 V6A）和背侧运动前区 F2 中存在显著的解码。这些数据支持了背内侧“伸手”区域在控制抓握方面的作用，并证明了在揭示大脑信息编码方面，使用功能磁共振成像 (fMRI) 数据的更敏感的多元分析来补充单变量分析的价值。
