Department of Psychology & Human Development, Peabody College, Vanderbilt University, 230 Appleton Place, Nashville, TN, 37203, USA.
Institute of Child Development, University of Minnesota, USA.
Neuroimage. 2017 Oct 1;159:430-442. doi: 10.1016/j.neuroimage.2017.08.023. Epub 2017 Aug 8.
Nonsymbolic numerical comparison task performance (whereby a participant judges which of two groups of objects is numerically larger) is thought to index the efficiency of neural systems supporting numerical magnitude perception, and performance on such tasks has been related to individual differences in math competency. However, a growing body of research suggests task performance is heavily influenced by visual parameters of the stimuli (e.g. surface area and dot size of object sets) such that the correlation with math is driven by performance on trials in which number is incongruent with visual cues. Almost nothing is currently known about whether the neural correlates of nonsymbolic magnitude comparison are also affected by visual congruency. To investigate this issue, we used functional magnetic resonance imaging (fMRI) to analyze neural activity during a nonsymbolic comparison task as a function of visual congruency in a sample of typically developing high school students (n = 36). Further, we investigated the relation to math competency as measured by the preliminary scholastic aptitude test (PSAT) in 10th grade. Our results indicate that neural activity was modulated by the ratio of the dot sets being compared in brain regions previously shown to exhibit an effect of ratio (i.e. left anterior cingulate, left precentral gyrus, left intraparietal sulcus, and right superior parietal lobe) when calculated from the average of congruent and incongruent trials, as it is in most studies, and that the effect of ratio within those regions did not differ as a function of congruency condition. However, there were significant differences in other regions in overall task-related activation, as opposed to the neural ratio effect, when congruent and incongruent conditions were contrasted at the whole-brain level. Math competency negatively correlated with ratio-dependent neural response in the left insula across congruency conditions and showed distinct correlations when split across conditions. There was a positive correlation between math competency in the right supramarginal gyrus during congruent trials and a negative correlation in the left angular gyrus during incongruent trials. Together, these findings support the idea that performance on the nonsymbolic comparison task relates to math competency and ratio-dependent neural activity does not differ by congruency condition. With regards to math competency, congruent and incongruent trials showed distinct relations between math competency and individual differences in ratio-dependent neural activity.
非符号数值比较任务的表现（即参与者判断两组物体中哪一组数量更大）被认为可以反映支持数值大小感知的神经系统的效率，并且这种任务的表现与数学能力的个体差异有关。然而，越来越多的研究表明，任务表现受到刺激的视觉参数的强烈影响（例如物体集合的表面积和点大小），因此与数学的相关性是由与视觉线索不一致的试验中的表现驱动的。目前几乎不知道非符号大小比较的神经相关性是否也受到视觉一致性的影响。为了研究这个问题，我们使用功能磁共振成像（fMRI）在一组典型的发展中高中生（n=36）中分析了非符号比较任务期间的神经活动，作为视觉一致性的函数。此外，我们还调查了与 10 年级初步学业能力测试（PSAT）测量的数学能力的关系。我们的结果表明，当从一致和不一致试验的平均值计算时，大脑区域的神经活动受到正在比较的点集的比率调制，正如大多数研究中一样，并且这些区域内的比率效应不随一致性条件而变化。然而，在整个大脑水平上对比一致和不一致条件时，在其他区域中，整体任务相关激活存在显著差异，而不是神经比率效应。在一致性条件下，数学能力与左脑岛的比率依赖神经反应呈负相关，并且在分裂条件下存在明显的相关性。在一致试验中，数学能力与右顶上回之间存在正相关，而在不一致试验中，左角回之间存在负相关。总之，这些发现支持这样一种观点，即非符号比较任务的表现与数学能力相关，并且比率依赖的神经活动不因一致性条件而不同。关于数学能力，在一致性和不一致性条件下，数学能力与比率依赖性神经活动的个体差异之间存在不同的关系。
