Monday, October 27, 2008

Mental Math and Dyscalculia in the Brain

From the Ansari lab, more data about how the brain does or does not do math. Having a spatial sense of number quantity is something that takes time to develop. Young children memorize number meanings (prefrontal), but having a sense of number quantity and inter-relatedness only develops as the parietal cortex matures.

fMRIs of children with developmental dyscalculia (often seen with dyslexia)confirm the absence of a distance effect (the farther apart numbers, the quicker the ability to judge that one number is larger) compared to typically-developing children. So a critical feature of developmental dyscalculia is a failure to have a spatial or distance sense of numbers. Having this 'feel' for numbers helps one perform mental math quickly; if lacking, calculations must be performed in a more ponderous fashion using much more working memory in the process.

Interesting to see that math achievement had a fairly direct relationship with the extent of white matter in the left corona radiata. No wonder that kids with various white matter / connectivity challenges (premature birth, birth stress, dyslexia, etc.) struggle with math achievement.

Ansari: Math, Development, and fMRI pdf
Unraveling Math Dyslexia