Valyear Kenneth F, Cavina-Pratesi Cristiana, Stiglick Amanda J, Culham Jody C
Neuroscience Program, University of Western Ontario, London, Ontario, Canada.
Neuroimage. 2007;36 Suppl 2:T94-T108. doi: 10.1016/j.neuroimage.2007.03.031. Epub 2007 Mar 31.
Neuroimaging investigations reliably describe a left-lateralized network of areas as underlying the representations of knowledge about familiar tools. Among the critical 'nodes' of the network, an area centered within the left intraparietal sulcus (IPS) is thought to be related to the motoric representations associated with familiar tools and their usage. This area is in the vicinity of an area implicated in the control of object-directed grasping actions: the anterior intraparietal area, AIP. The current study aimed to evaluate whether this tool-related intraparietal activity could be accounted for by the graspable nature of tools or whether it was due to additional factors such as the functionality of tools. First, we found that during a naming task activation within a discrete region of the left anterior intraparietal cortex was higher for tools than for graspable objects, but did not differ between graspable and non-graspable objects. In addition, the peak activity associated with tool naming was found to be largely distinct and consistently posterior to that associated with real object grasping. A separate region, anterior to the tool-selective focus and possibly overlapping with AIP, demonstrated weak selectivity for both tools and graspable objects relative to non-graspable objects. These findings indicate that this tool-selective area at the anterior end of the left IPS is both separable from the grasp-related intraparietal activity and, consistently, it does not simply reflect the processing of grasping affordances. Taken together, these results suggest that object graspability alone cannot account for the left intraparietal activity driven by the naming of tools. Instead, this activity may relate to learned motor representations associated with the skillful use of familiar tools.
神经影像学研究可靠地描述了一个以左侧为主的区域网络，该网络是熟悉工具知识表征的基础。在该网络的关键“节点”中，以左侧顶内沟（IPS）为中心的一个区域被认为与熟悉工具及其使用相关的运动表征有关。该区域靠近一个与控制目标导向抓握动作有关的区域：前顶内区，即AIP。当前的研究旨在评估这种与工具相关的顶内活动是由工具的可抓握性质引起的，还是由诸如工具功能等其他因素导致的。首先，我们发现，在一项命名任务中，左侧前顶内皮层一个离散区域内的激活对于工具而言高于可抓握物体，但在可抓握物体和不可抓握物体之间没有差异。此外，发现与工具命名相关的峰值活动在很大程度上与真实物体抓握相关的活动不同，且始终位于其后方。一个单独的区域，位于工具选择性焦点前方，可能与AIP重叠，相对于不可抓握物体，对工具和可抓握物体均表现出较弱的选择性。这些发现表明，左侧IPS前端的这个工具选择性区域既与抓握相关的顶内活动可分离，而且一致地，它并不能简单地反映对抓握能力的处理。综上所述，这些结果表明，仅物体的可抓握性不能解释由工具命名驱动的左侧顶内活动。相反，这种活动可能与与熟练使用熟悉工具相关的习得运动表征有关。
