PT  - JOURNAL ARTICLE
AU  - Michelle AN La
AU  - Debjani Saha
AU  - Karen F Berman
AU  - Hao Yang Tan
TI  - Dysfunctional and compensatory brain networks underlying math fluency
AID  - 10.1101/752089
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 752089
4099  - http://biorxiv.org/content/early/2019/09/02/752089.short
4100  - http://biorxiv.org/content/early/2019/09/02/752089.full
AB  - Poor math fluency, or timed calculation (TC) performance, is a characteristic of dyscalculia, a common cause of poor educational and occupational outcomes. Here, we examined neural substrates of dysfunctional math fluency and potential compensatory mechanisms. We performed functional MRI scans of participants with divergent performance on an event-related TC paradigm (poor TC, <0.5 accuracy, n=34; vs. controls, accuracy>0.8, n=34). Individuals with poor TC had decreased intraparietal sulcus (IPS) engagement, and decreased IPS-striatal and IPS-prefrontal effective connectivity. We next examined an independent well-performing sample (TC accuracy>0.8, n=100), stratified according to relatively low-versus high-IPS activation during TC. Relatively reduced IPS engagement, or patterns of IPS-related effective connectivity similar to those with poor TC, appeared to be compensated for by increased engagement of effective connectivity involving fusiform gyrus, angular gyrus, inferior frontal gyrus and striatum. Neural connectivity involving high-level visual processing in fusiform gyrus and related ventral cortical networks may be relevant in compensatory function ameliorating aspects of dyscalculia and mathematical difficulty.