Department of Psychology and Human Development, Vanderbilt University, Nashville, TN, USA.
Institut des Sciences Cognitives Marc Jeannerod, UMR 5304, Centre National de la Recherche Scientifique (CNRS) & Université de Lyon, Bron, France.
Neuroimage. 2018 Dec;183:859-871. doi: 10.1016/j.neuroimage.2018.08.074. Epub 2018 Sep 4.
Models of the neural basis of arithmetic argue that left inferior frontal cortex is involved in cognitive control of verbal representations of math facts in left lateral temporal cortex, whereas bilateral intra-parietal cortex is involved in numerical calculation. Lower levels of math competence for multiplications is associated with greater effortful retrieval because of less robust verbal representations and the engagement of numerical operations as a back-up strategy. Previous studies on multiplication have focused on brain activation in isolated nodes of the network, so we do not know how functional connectivity between these nodes is related to competence. Moreover, previous studies have not employed longitudinal designs, so we do not know how changes in multiplication performance over time is related to changes in its neural basis. The objective of this study was to investigate how changes in multiplication task performance is associated with changes in functional connectivity of temporal cortex with frontal and parietal cortices. Longitudinal data was collected from 45 children, with an average 2.2-year interval between the two sessions, when they were about 11 years old at time 1 (T1) and 13 years old at time 2 (T2). A Psychophysiological Interaction (PPI) analysis was carried out by defining the seed in the temporal cortex (i.e. posterior superior and middle temporal gyri) and examining changes in connectivity with frontal cortex (i.e. left inferior frontal gyrus) as well as parietal cortex (i.e. left and right inferior and superior parietal lobules). We found that children who did not improve in a multiplication task showed greater levels of functional connectivity of left temporal cortex with left inferior frontal gyrus (IFG) and left intraparietal sulcus (IPS) at T2, as compared to their peers who improved. The cluster showing greater levels of connectivity in the left IFG at T2 for the Non-improvers overlapped a cluster independently identified by a verbal localizer task and the cluster showing greater levels of connectivity in the left IPS Non-improvers overlapped a cluster independently identified by a numerosity localizer task. These results suggest that lack of improvement in multiplications are associated with greater cognitive control of verbal representations and greater engagement of numerical operations.
乘法能力较低与更费力的检索有关，因为较弱的言语表示和作为备用策略的数值运算的参与。以前关于乘法的研究主要集中在网络的孤立节点的大脑激活上，因此我们不知道这些节点之间的功能连接如何与能力相关。此外，以前的研究没有采用纵向设计，因此我们不知道乘法表现随时间的变化如何与其神经基础的变化相关。本研究的目的是研究乘法任务表现的变化如何与颞叶与额叶和顶叶皮质之间的功能连接的变化相关。从 45 名儿童中收集了纵向数据，两次之间的平均间隔为 2.2 年，他们在第一次（T1）和第二次（T2）时大约 11 岁和 13 岁。通过在颞叶（即后上和中颞回）定义种子并检查与额叶（即左额下回）以及顶叶（即左和右顶下和顶上小叶）的连接变化，进行了心理生理相互作用（PPI）分析。我们发现，在乘法任务中没有改善的儿童在 T2 时，左侧颞叶与左侧额下回（IFG）和左侧顶内沟（IPS）的功能连接水平较高，而与其同龄人相比。在 T2 时，非改善者的左侧 IFG 显示出更高水平的连接的聚类与通过言语定位器任务独立识别的聚类重叠，而在 T2 时，非改善者的左侧 IPS 显示出更高水平的连接的聚类与通过数值定位器任务独立识别的聚类重叠。这些结果表明，乘法能力的提高与言语表示的认知控制增加和数值运算的参与增加有关。
