Institut de Recherche en Sciences Psychologiques and Institute of Neuroscience, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
Neuropsychologia. 2013 Aug;51(10):1925-32. doi: 10.1016/j.neuropsychologia.2013.06.004. Epub 2013 Jun 15.
When asked to bisect mentally numerical intervals, neglect patients show a displacement of the numerical midpoint similar to the one observed in physical line bisection. This spatial-numerical bias has been taken as evidence of the spatial nature of numerical magnitude representations. However, to date, neuropsychological studies in neglect patients have only used symbolic numerical material. Here, we compare the results of patients with right-hemisphere damage with and without unilateral left neglect and age-matched healthy control participants in two numerical comparison tasks using symbolic and non-symbolic materials, in order to determine whether the representation of non-symbolic numerosities was altered or not by the presence of neglect. When asked to judge if an Arabic digit or a sequence of flashed dots was smaller or larger than a reference value (i.e., 5), the responses of neglect patients to smaller magnitudes (i.e., 4) were impaired. Moreover, only neglect patients presented an asymmetrical distance effect (i.e., an enhanced effect only for stimuli of smaller numerical magnitude than the reference). These results provide the first direct evidence of a spatial bias in non-symbolic numerosity in neglect patients, and support the existence of common processing mechanisms and/or a representational system for symbolic and non-symbolic inputs.
当被要求在心理上划分数值区间时，忽略患者表现出与物理线二分法中观察到的类似的数值中点的位移。这种空间-数值偏差被认为是数值大小表示的空间性质的证据。然而，迄今为止，对忽略患者的神经心理学研究仅使用了符号数值材料。在这里，我们比较了右半球损伤且伴有或不伴有单侧左侧忽略的患者以及年龄匹配的健康对照组参与者在使用符号和非符号材料的两个数值比较任务中的结果，以确定忽略是否改变了非符号数值的表示。当被要求判断阿拉伯数字或闪烁点序列是否小于或大于参考值（即 5）时，忽略患者对较小数值（即 4）的反应受到损害。此外，只有忽略患者表现出非对称距离效应（即，仅对小于参考值的较小数值刺激有增强效应）。这些结果提供了直接证据，证明了忽略患者在非符号数值中存在空间偏差，并支持了符号和非符号输入的共同处理机制和/或表示系统的存在。
