Holmes Nicholas P, Sanabria Daniel, Calvert Gemma A, Spence Charles
Department of Experimental Psychology, Oxford University, Oxford, UK; Department of Psychology, Bath University, Bath, UK.
Cortex. 2007 Apr;43(3):469-89. doi: 10.1016/s0010-9452(08)70471-4.
The active and skilful use of tools has been claimed to lead to the "extension" of the visual receptive fields of single neurons representing peripersonal space--the visual space immediately surrounding one's body parts. While this hypothesis provides an attractive and potentially powerful explanation for one neural basis of tool-use behaviours in human and nonhuman primates, a number of competing hypotheses for the reported behavioural effects of tool-use have not yet been subjected to empirical test. Here, we report five behavioural experiments in healthy human participants (n=120) involving the effects of tool-use on visual-tactile interactions in peripersonal space. Specifically, we address the possibility that the use of only a single tool, which is typical of many neuropsychological studies of tool-use, induces a spatial allocation of attention towards the side where the tool is held. Participants' tactile discrimination responses were more strongly affected by visual stimuli presented on the right side when they held a single tool on the right, compared to visual stimuli presented on the left. When [corrected] two tools were held, one in each hand, this spatial effect disappeared. Our results are incompatible with the hypothesis that tool-use extends peripersonal space, and suggest instead that the use and/or manipulation of [corrected] tools results in an automatic multisensory shift of spatial attention to the side of space where the tip of the tool is actively held. These results have implications for many of the cognitive neuroscientific studies of tool-use published to date.
有人认为，积极且熟练地使用工具会导致代表个人周边空间（即紧邻身体各部位的视觉空间）的单个神经元的视觉感受野“扩展”。虽然这一假说为人类和非人类灵长类动物工具使用行为的一种神经基础提供了颇具吸引力且可能强有力的解释，但对于工具使用所报告的行为效应，一些相互竞争的假说尚未经过实证检验。在此，我们报告了针对120名健康人类参与者开展的五项行为实验，这些实验涉及工具使用对个人周边空间中视觉 - 触觉交互的影响。具体而言，我们探讨了仅使用单一工具（这在许多工具使用的神经心理学研究中很典型）是否会引起对持工具一侧空间的注意力空间分配。与左侧呈现的视觉刺激相比，当参与者右手持单一工具时，右侧呈现的视觉刺激对其触觉辨别反应的影响更强。当双手各持一个工具时，这种空间效应就消失了。我们的结果与工具使用扩展个人周边空间这一假说不相符，相反，这表明工具的使用和/或操作会导致空间注意力自动向积极持握工具尖端的空间一侧进行多感官转移。这些结果对迄今为止发表的许多工具使用的认知神经科学研究具有启示意义。
