Mathematical ability is shaped by a complex interaction between genetic and environmental factors. Many genes have been found to be associated with mathematical performance, and many of these genes also express proteins in nerve cell tissue which are found in the brain. However, little is known about how expression patterns of math-related genes are distributed over the developing human brain. As a result, it is an open question how genetic variation could give rise to differences in mathematical ability. And so, the researchers of this study decided to explore and address this gap in knowledge.
The aim of the study was to explore associations between known math candidate genes and brain structure in young children that had not yet received math instruction. The researchers also investigated longitudinally whether these associations would predict math performance in school.
The researchers selected and analysed 18 single nucleotide polymorphisms (SNPs; these represent genetic variants/differences in a single DNA building block, called a nucleotide) in 10 genes previously found to be significantly associated with mathematical performance. They then examined the relationship between these variants and the volume of grey matter (which mainly consists of nerve cell bodies), across the whole brain in a total of 178 3-6-year-old children who underwent magnetic resonance imaging (MRI scan). Finally, they identified brain regions whose grey matter volumes could predict math test scores in second grade (7–9-year-old children).
Out of the 10 genes explored, the researchers found that variants in just 1 gene called ROBO1, a gene that regulates prenatal growth of the outermost layer of neural tissue in the brain, are associated with the grey matter volume in the right parietal lobe, a key brain region for quantity representation. Moreover, grey matter volume within these regions predicted the children’s math test scores at 7-9 years of age.
The results of this study suggest that individual differences in right parietal cortex growth might be an intermediate phenotype (phenotype of an offspring expressing a mix of the parent’s phenotype) filling the missing explanations in previously reported associations between DNA variation and mathematical performance. This interpretation lines up with many studies showing that the parietal lobe specifically contributes to mathematical cognition from childhood on, and keeps this decisive role in adulthood. In particular, structures of the parietal lobe, such as the intraparietal sulcus and the superior parietal lobule, provide the neural resources for quantity detection, which remains an essential basic component even for higher-order mathematical problem solving.
According to the researchers, the results of this study suggest that genetic variability might shape mathematical ability by influencing the early development of the brain’s basic quantity processing system.
Original Source: Skeide MA, Wehrmann K, Emami Z, Kirsten H, Hartmann AM and Rujescu D, (2020). Neurobiological origins of individual differences in mathematical ability. PLOS Biology. https://doi.org/10.1371/journal.pbio.3000871