Bédard Patrick, Sanes Jerome N
Department of Neuroscience, Alpert Medical School, Brown University, 185 Meeting St., Box GL-N, Providence, RI 02912, USA.
J Neurophysiol. 2009 Feb;101(2):834-42. doi: 10.1152/jn.90683.2008. Epub 2008 Nov 12.
Humans commonly use their hands to move and to interact with their environment by processing visual and proprioceptive information to determine the location of a goal-object and the initial hand position. It remains elusive, however, how the human brain fully uses this sensory information to generate accurate movements. In monkeys, it appears that frontal and parietal areas use and combine gaze and hand signals to generate movements, whereas in humans, prior work has separately assessed how the brain uses these two signals. Here we investigated whether and how the human brain integrates gaze orientation and hand position during simple visually triggered finger tapping. We hypothesized that parietal, frontal, and subcortical regions involved in movement production would also exhibit modulation of movement-related activation as a function of gaze and hand positions. We used functional MRI to measure brain activation while healthy young adults performed a visually cued finger movement and fixed gaze at each of three locations and held the arm in two different configurations. We found several areas that exhibited activation related to a mixture of these hand and gaze positions; these included the sensory-motor cortex, supramarginal gyrus, superior parietal lobule, superior frontal gyrus, anterior cingulate, and left cerebellum. We also found regions within the left insula, left cuneus, left midcingulate gyrus, left putamen, and right tempo-occipital junction with activation driven only by gaze orientation. Finally, clusters with hand position effects were found in the cerebellum bilaterally. Our results indicate that these areas integrate at least two signals to perform visual-motor actions and that these could be used to subserve sensory-motor transformations.
人类通常通过处理视觉和本体感觉信息来确定目标物体的位置和手部的初始位置，从而用手与周围环境进行互动并移动。然而，人类大脑如何充分利用这些感官信息来产生精确的动作，目前仍不清楚。在猴子身上，额叶和顶叶区域似乎会利用并整合注视和手部信号来产生动作，而在人类中，之前的研究分别评估了大脑如何使用这两种信号。在这里，我们研究了在简单的视觉触发手指敲击过程中，人类大脑是否以及如何整合注视方向和手部位置。我们假设，参与动作产生的顶叶、额叶和皮层下区域也会根据注视和手部位置，表现出与动作相关的激活调节。我们使用功能磁共振成像来测量大脑激活情况，在此期间，健康的年轻成年人进行视觉提示的手指动作，并在三个位置中的每一个位置固定注视，同时将手臂保持在两种不同的姿势。我们发现了几个区域，这些区域的激活与这些手部和注视位置的组合有关；其中包括感觉运动皮层、缘上回、顶上小叶、额上回、前扣带回和左小脑。我们还发现，左侧脑岛、左侧楔叶、左侧中央扣带回、左侧壳核和右侧颞枕交界处的一些区域，其激活仅由注视方向驱动。最后，在双侧小脑中发现了受手部位置影响的簇。我们的结果表明，这些区域整合了至少两种信号来执行视觉运动动作，并且这些信号可用于辅助感觉运动转换。
