Functional neuroanatomy of arithmetic and word reading and its relationship to age

Abstract

Arithmetic and written language are uniquely human skills acquired during early schooling and used daily. While prior studies have independently characterized the neural bases for arithmetic and reading, here we examine both skills in a single study to capture their shared and unique cognitive mechanisms, as well as the role of age/experience in modulating their neural representations. We used functional MRI in 7- to 29-year-olds who performed single-digit subtraction, single-digit addition, and single-word reading. Using a factorial design, we examined the main effects of Task (subtraction, addition, reading) and Age (as a continuous variable), and their interactions. A main effect of Task revealed preferential activation for subtraction in bilateral intraparietal sulci and supramarginal gyri, right insula, inferior frontal gyrus, and cingulate. The right middle temporal gyrus and left superior temporal gyrus were preferentially active for both addition and reading, and left fusiform gyrus was preferentially active for reading. A main effect of Age revealed increased activity in older participants in right angular gyrus, superior temporal sulcus, and putamen, and less activity in left supplementary motor area, suggesting a left frontal to right temporo-parietal shift of activity with increasing age/experience across all tasks. Interactions for Task by Age were found in right hippocampus and left middle frontal gyrus, with older age invoking greater activity for addition and at the same time less activity for subtraction and reading. Together, in a study conducted in the same participants using similar task and acquisition parameters, the results reveal the neural substrates of these educationally relevant cognitive skills in typical participants in the context of age/experience.

Mechanisms of interactive specialization and emergence of functional brain circuits supporting cognitive development in children

“…A uniquely human cognitive skill, symbolic arithmetic is especially relevant for testing the IS framework given its importance in children's cognitive and academic skill development. [23][24][25] Furthermore, this domain involves distributed brain areas whose engagement changes dynamically with skill acquisition. 26 Core functional systems involved in symbolic arithmetic include a system for numerical quantity representation anchored in the intraparietal sulcus (IPS), and a visual number form processing system anchored in ventrotemporal occipital cortex (VTOC).…”

Neurobiological bases of reading disorder part II: The importance of developmental considerations in typical and atypical reading

“…To acquire fluent reading, developing well-organized and connected neural systems is necessary (Blomert, 2011;Wandell, Rauschecker, & Yeatman, 2012). Taken together, cross-sectional studies (Evans, Flowers, Luetje, Napoliello, & Eden, 2016;Saygin et al, 2013;Turkeltaub, Gareau, Flowers, Zeffiro, & Eden, 2003) and longitudinal studies (Brem et al, 2010;Linkersdorfer et al, 2015;Lu et al, 2007;Maurer, Brem, Bucher, & Brandeis, 2005;Maurer et al, 2006;Myers et al, 2014;Yamada et al, 2011) indicate that the developments of brain structure and function are closely associated with typical reading acquisition. Synthesis of functional findings shows that the left temporo-parietal and occipito-temporal regions are recruited early (Brem et al, 2010), and reading development is thought to involve the initial engagement of the left and right occipito-temporal and temporo-parietal regions simultaneously, followed by disengagement of right hemisphere regions (Brem et al, 2010;Maurer et al, 2005; Turkeltaub FIGURE 1 (a) Central cortical nodes and connections of four main functional systems for reading, including the dorsal phonological system, the ventral orthographic system, the distributed semantic system, and the articulatory system, are presented.…”

Separate lanes for math and reading in the white matter highways of the human brain

“…This fundamental gap in knowledge is due to four main reasons: First, substantially more neuroscience research has been done on the neural bases of reading 4,5 than the neural bases of math 6 . Second, most prior studies have evaluated either the neural bases of math 7,[24][25][26][27] or the neural bases reading 18,21,[28][29][30][31][32][33] , but not both systems within the same individuals (for an exception see 2 ). Third, no study directly examined the white matter connections associated with functional regions involved in mathematical processing within the same individuals.…”

“…In contrast, a few previous studies have examined which white matter fascicles connect to a key cortical region of the reading network, namely the VWFA, evaluating functional regions and white matter connections within the same subjects [18][19][20] . Thus, the goal of this study is twofold: (1) identify and quantify the white matter connections of cortical regions involved in mathematical processing within individual subjects and (2) determine which aspects of this white matter are unique to the math network, and which are shared with the reading network.…”

“…1c), as well as, which fascicles these fWMTs travel through. This approach allowed us to determine (1) what are the white matter tracts of the math and reading networks, (2) which fascicles are network unique and which contribute to both math and reading, and (3) whether white matter tracts associated with math and reading are physically intertwined or segregated within a fascicle. Finally, the goal of the qMRI measurements was to test if there are differences in structural white matter characteristics across the reading and math networks.…”