Department of Psychology, Princeton University, Princeton, NJ, USA.
J Neurophysiol. 2013 Jun;109(12):2883-96. doi: 10.1152/jn.00658.2012. Epub 2013 Mar 27.
Humans have an amazing ability to quickly and efficiently recognize and interact with visual objects in their environment. The underlying neural processes supporting this ability have been mainly explored in the ventral visual stream. However, the dorsal stream has been proposed to play a critical role in guiding object-directed actions. This hypothesis is supported by recent neuroimaging studies that have identified object-selective and tool-related activity in human parietal cortex. In the present study, we sought to delineate tool-related information in the anterior portions of the human intraparietal sulcus (IPS) and relate it to recently identified motor-defined and topographic regions of interest (ROIs) using functional MRI in individual subjects. Consistent with previous reports, viewing pictures of tools compared with pictures of animals led to a higher blood oxygenation level-dependent (BOLD) response in the left anterior IPS. For every subject, this activation was located lateral, anterior, and inferior to topographic area IPS5 and lateral and inferior to a motor-defined human parietal grasp region (hPGR). In a separate experiment, subjects viewed pictures of tools, animals, graspable (non-tool) objects, and scrambled objects. An ROI-based time-course analysis showed that tools evoked a stronger BOLD response than animals throughout topographic regions of the left IPS. Additionally, graspable objects evoked stronger responses than animals, equal to responses to tools, in posterior regions and weaker responses than tools, equal to responses to animals, in anterior regions. Thus the left anterior tool-specific region may integrate visual information encoding graspable features of objects from more posterior portions of the IPS with experiential knowledge of object use and function to guide actions.
人类具有快速而有效地识别和与环境中视觉对象交互的惊人能力。支持这种能力的潜在神经过程主要在腹侧视觉流中得到了探索。然而，背侧流被认为在指导物体定向动作方面起着关键作用。这一假设得到了最近的神经影像学研究的支持，这些研究在人类顶叶皮层中发现了与物体选择性和工具相关的活动。在本研究中，我们试图描绘人类顶内沟（IPS）前部与工具相关的信息，并使用个体受试者的功能磁共振成像（fMRI）将其与最近确定的与运动相关的和地形学上的感兴趣区域（ROI）相关联。与之前的报告一致，与动物图片相比，观看工具图片会导致左前 IPS 中的血氧水平依赖（BOLD）反应更高。对于每个受试者，这种激活位于 IPS5 地形区域的外侧、前方和下方，并且位于运动定义的人类顶叶抓握区域（hPGR）的外侧和下方。在另一个实验中，受试者观看工具、动物、可抓握（非工具）物体和乱序物体的图片。基于 ROI 的时程分析显示，在左 IPS 的地形区域中，工具比动物引起更强的 BOLD 反应。此外，可抓握物体在后部区域引起的反应比动物强，与工具的反应相等，而在前部区域引起的反应比工具弱，与动物的反应相等。因此，左侧的前部工具特异性区域可能整合了来自 IPS 更后部区域的物体可抓握特征的视觉信息编码，以及对物体使用和功能的经验知识，以指导动作。
