Multi-method brain imaging reveals impaired representations as well as altered connectivity in adults with dyscalculia

Abstract

2 SummaryTwo hypotheses have been proposed about the etiology of neurodevelopmental disorders: representation impairments versus disrupted access to representations. We implemented a multi-method brain imaging approach to directly compare the representation vs. access hypotheses in dyscalculia, a highly prevalent but understudied neurodevelopmental disorder in learning to calculate. We combined several magnetic resonance imaging methods and analyses, including multivariate analyses, functional and structural connectivity, and voxelbased morphometry analysis, in a sample of 24 adults with dyscalculia and 24 carefully matched controls. Results showed a clear deficit in the non-symbolic magnitude representations in parietal, temporal, and frontal regions in dyscalculia. We also observed hyper-connectivity in visual brain regions and increased grey matter volume in the default mode network in adults with dyscalculia. Hence, dyscalculia is related to a combination of diverse neural markers which are altogether distributed across a substantial portion of cerebral cortex, supporting a multifactorial model of this neurodevelopmental disorder.

Dysfunctions associated with the intraparietal sulcus and a distributed network in individuals with math learning difficulties: An ALE meta‐analysis

“…Out meta-analysis also characterized the distributed brain networks beyond the IPS and their directional effects observed in MLD, supporting the multifaceted cognitive impairment hypothesis (Bulthé et al, 2019;Menon, 2014;Menon et al, 2020). Besides right anterior IPS and left FG/ITG, our meta-analysis also showed consistent findings with previous meta-analyses on math processing in the right anterior insula, mPFC, left IPL/SPL, right FG, dACC, and claustrum (Arsalidou et al, 2018;Arsalidou & Taylor, 2011;Hawes et al, 2019;Kaufmann et al, 2011).…”

“…One leading theory about MLD is their inability to process quantity information anchored in the IPS (Bulthé et al, 2019;Dehaene & Wilson, 2007;Devlin & Price, 2007;Iuculano, 2016;Von Aster & Shalev, 2007). Consistent with this view, namely the core quantity deficit hypothesis, our analysis showed the most consistent effect in right IPS and adjacent regions including SPL and IPL in MLD compared to TD.…”

“…From our meta-analysis, we found the most consistently reported brain region was the right lateral parietal cortex, centering around the IPS. The IPS serves as a key neurobiological basis for MLD and potentially their deficits in math tasks (Ashkenazi et al, 2012;Bulthé et al, 2019;Menon et al, 2020;Price et al, 2007). The right IPS, along with the adjacent SPL and IPL, are central for math processing across different types of tasks such as quantity comparisons (Chassy & Grodd, 2012;Sokolowski et al, 2017) and exact or approximate calculation tasks (Arsalidou & Taylor, 2011;Ashkenazi et al, 2012;Kucian et al, 2008).…”

“…Accordingly, individuals with MLD were shown to have significantly lower working memory abilities (Mabbott & Bisanz, 2008) and visuospatial skills (Lambert & Spinath, 2018) compared to TD. Ample findings also reported that individuals with MLD had atypical brain activations or aberrant multivoxel representations in distributed regions (Bulthé et al, 2019;Chen et al, 2021;Iuculano et al, 2015;Kucian et al, 2011;Rosenberg-Lee et al, 2015;Rotzer et al, 2008), such as the anterior insula, the dorsolateral and ventrolateral prefrontal cortices (dlPFC and vlPFC), fusiform gyrus along with inferior temporal gyrus (FG/ITG). Therefore, the updated theory, known as the multifaceted cognitive impairment hypothesis, proposes that MLD is associated with dysfunctions not only in the IPS for quantity processing but also a distributed brain networks for various domain-general functions (Ashkenazi et al, 2012;Iuculano, 2016;Menon et al, 2020;Peters & De Smedt, 2018;Rapin, 2016;Vogel & De Smedt, 2021).…”

Mapping numerical perception and operations in relation to functional and anatomical landmarks of human parietal cortex

“…FMRI studies in developmental dyscalculia showed abnormal activations of, among others, the mid-posterior parietal cortex during symbolic (Mussolin et al, 2010) and nonsymbolic (Bulthe et al, 2018;Kaufmann et al, 2009a;Price et al, 2007) numerical comparisons, ordinality judgements (Kaufmann et al, 2009b), approximate calculation (Kucian et al, 2006) or simple arithmetical verification (Ashkenazi et al, 2009;Iuculano et al, 2015;Rosenberg-Lee et al, 2015) in dyscalculic children with respect to controls.…”