Neural Correlates of Numerical Estimation: The Role of Strategy Use

Abstract

Introduction: Computation estimation is the ability to provide an approximate answer to a complex arithmetic problem without calculating it exactly. Despite its importance in daily life, the neuronal network underlying computation estimation is largely unknown. Methods: We looked at the neuronal correlates of two computational estimation strategies: approximated calculation and sense of magnitude (SOM)–intuitive representation of magnitude, without calculation. During an fMRI scan, thirty-one college students judged whether the result of a two-digit multiplication problem was larger or smaller than a given reference number. In two different blocks, they were asked to use a specific strategy (AC or SOM). Results: The two strategies activated brain regions related to calculation, numerical cognition, decision-making, and working memory. AC more than SOM elicited activations in multiple, domain-specific brain regions in the parietal lobule, including the left SMG (BA 40), the bilateral superior parietal lobule (BA 7), and the right inferior parietal lobule (BA 7). The activation level of the IFG was positively correlated to individual accuracy, indicating that the IFG has an essential role in both strategies. Conclusions: These finding suggest that the analogic code of magnitude is more involved in the AC than the SOM strategy.

Challenges in Understanding Numerical Learning: Editorial for Brain Sciences Special Issue “Neurocognitive Signatures of Math (Learning) across the Lifespan and Their Interrelation with Other Aspects of Cognition and Emotion”

“…Interestingly, the use of anchor points was also associated with faster responses in mental arithmetic. On the neural level, Ashkenazi et al [ 11 ] evaluated the neural networks underlying two different computation estimation strategies using functional magnetic resonance imaging (fMRI) in adults: approximate calculation and sense of magnitude intuitive representation. Approximate calculation was associated with stronger magnitude-specific activation in multiple parietal regions than sense of magnitude intuitive representation, while the inferior frontal gyrus seemed to be essential for both strategies.…”