The neural substrate of numerical cognition in dyscalculia revealed by eye tracking and ultra-high field 7T functional magnetic imaging

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What is the foundation of numerical thinking and why do some people struggle with math so much? For children with Developmental Dyscalculia (DD) understanding even the most basic numerical and arithmetical concepts can pose a major challenge, despite their normal intelligence and schooling opportunities. Different etiological accounts attempted to identify the neurocognitive basis of this developmental disorder, yet a universally recognized diagnostic measure of DD is still missing. One possible cause of DD is the lack of a functional “number sense”, the capability to estimate the approximate number of objects in a visual scene, which is thought to be the precursor of formal mathematics. A different account attributes DD to the suboptimal recruitment of general cognitive functions (e.g. attention and cognitive control) and denies any role of the number sense in mathematical learning. Here I propose a third view where domain general cognitive functions are strongly but specifically affected in DD, being maximally dysfunctional when individuals have to deal with numerical quantities. The ambitious aim of DYSC-EYE-7T is to evaluate the role of attention in numerical cognition by means of eye tracking, pupillometry and ultra-high field (7T) imaging. For the first time, these techniques will be used to identify objective and reliable biomarkers of numerical processing: I will develop indices based on eye-movement speed and pupil-size modulation to track individuals’ focus of attention during numerical processing and detect dysfunctional strategies in DD. These indices will be combined with multivariate analysis of functional imaging data to read-out the neural representation of number at high resolution and to identify the cortical origin of the specific attentional deficit in DD. A full understanding of the neurocognitive basis of DD and the validation of unobtrusive methods suited for children will pave the way for precocious diagnosis and more effective interventions.