Cohen Kadosh Roi, Cohen Kadosh Kathrin, Linden David E J, Gevers Wim, Berger Andrea, Henik Avishai
Ben-Gurion University of the Negev, Beer Sheva, Israel.
J Cogn Neurosci. 2007 Jun;19(6):957-70. doi: 10.1162/jocn.2007.19.6.957.
Whether the human brain is equipped with a special neural substrate for numbers, or rather with a common neural substrate for processing of several types of magnitudes, has been the topic of a long-standing debate. The present study addressed this question by using functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs) together with the size-congruity paradigm, a Stroop-like task in which numerical values and physical sizes were varied independently. In the fMRI experiment, a region-of-interest analysis of the primary motor cortex revealed interference effects in the hemisphere ipsilateral to the response hand, indicating that the stimulus-stimulus conflict between numerical and physical magnitude is not completely resolved until response initiation. This result supports the assumption of distinct comparison mechanisms for physical size and numerical value. In the ERP experiment, the cognitive load was manipulated in order to probe the degree to which information processing is shared across cognitive systems. As in the fMRI experiment, we found that the stimulus-stimulus conflict between numerical and physical magnitude is not completely resolved until response initiation. However, such late interaction was found only in the low cognitive load condition. In contrast, in the high load condition, physical and numerical dimensions interacted only at the comparison stage. We concluded that the processing of magnitude can be subserved by shared or distinct neural substrates, depending on task requirements.
人类大脑是否配备了专门用于处理数字的神经基质，或者更确切地说，是否配备了用于处理多种类型数量的通用神经基质，一直是一个长期争论的话题。本研究通过使用功能磁共振成像（fMRI）和事件相关电位（ERP），结合大小一致性范式来解决这个问题，大小一致性范式是一种类似斯特鲁普任务，其中数值和物理大小是独立变化的。在fMRI实验中，对初级运动皮层进行感兴趣区域分析，发现在与反应手同侧的半球存在干扰效应，这表明数值和物理大小之间的刺激-刺激冲突直到反应开始时才完全解决。这一结果支持了物理大小和数值具有不同比较机制的假设。在ERP实验中，通过操纵认知负荷来探究信息处理在不同认知系统之间共享的程度。与fMRI实验一样，我们发现数值和物理大小之间的刺激-刺激冲突直到反应开始时才完全解决。然而，这种晚期相互作用仅在低认知负荷条件下被发现。相比之下，在高负荷条件下，物理维度和数值维度仅在比较阶段相互作用。我们得出结论，数量的处理可以由共享或不同的神经基质来支持，这取决于任务要求。
