Center for Mind/Brain Sciences, University of Trento, 38100 Mattarello, Italy.
Center for Mind/Brain Sciences, University of Trento, 38100 Mattarello, Italy; Department of Psychology, Harvard University, MA 02138, Cambridge, USA.
Neuroimage. 2014 Jul 1;94:138-146. doi: 10.1016/j.neuroimage.2014.03.017. Epub 2014 Mar 17.
To grasp an object, we need to move the arm toward it and assume the appropriate hand configuration. While previous studies suggested dorsomedial and dorsolateral pathways in the brain specialized respectively for the transport and grip components, more recent studies cast doubt on such a clear-cut distinction. It is unclear, however, to which degree neuronal populations selective for the two components overlap, and if so, to which degree they interact. Here, we used multivoxel pattern analysis (MVPA) of functional magnetic resonance imaging (fMRI) data to investigate the representation of three center-out movements (touch, pincer grip, whole-hand grip) performed in five reach directions. We found selectivity exclusively for reach direction in posterior and rostral superior parietal lobes (SPLp, SPLr), supplementary motor area (SMA), and the superior portion of dorsal premotor cortex (PMDs). Instead, we found selectivity for both grip type and reach direction in the inferior portion of dorsal premotor cortex (PMDi), ventral premotor cortex (PMv), anterior intraparietal sulcus (aIPS), primary motor (M1), somatosensory (S1) cortices and the anterior superior parietal lobe (SPLa). Within these regions, PMv, M1, aIPS and SPLa showed weak interactions between the transport and grip components. Our results suggest that human PMDi and S1 contain both grip- and reach-direction selective neuronal populations that retain their functional independence, whereas this information might be combined at the level of PMv, M1, aIPS, and SPLa.
为了抓取物体，我们需要将手臂伸向物体，并采取适当的手部姿势。虽然之前的研究表明大脑中的背内侧和背外侧通路分别专门负责运输和握持组件，但最近的研究对这种明确的区分提出了质疑。然而，不清楚专门针对这两个组件的神经元群体重叠到什么程度，如果重叠，它们的相互作用程度如何。在这里，我们使用功能磁共振成像 (fMRI) 数据的多体素模式分析 (MVPA) 来研究在五个到达方向上进行的三个中心向外运动（触摸、钳子抓握、全手抓握）的表示。我们发现选择性仅存在于后顶叶和前顶叶（SPLp、SPLr）、辅助运动区（SMA）和背侧运动前皮质（PMD）的上部。相反，我们发现了在背侧运动前皮质下部（PMDi）、腹侧运动前皮质（PMv）、前内顶叶沟（aIPS）、初级运动（M1）、躯体感觉（S1）皮质和前上顶叶（SPLa）中，对抓握类型和到达方向都具有选择性。在这些区域内，PMv、M1、aIPS 和 SPLa 之间显示出运输和握持组件之间的弱相互作用。我们的结果表明，人类 PMDi 和 S1 包含对握持和到达方向都具有选择性的神经元群体，这些群体保留了其功能独立性，而这些信息可能在 PMv、M1、aIPS 和 SPLa 水平上进行组合。
