Frisem

Pedro Pinheiro-Chagas, a postdoc with Professor Josef Parvizi, Department of Neurology, Stanford University

Title: Characterizing the neurocognitive mechanisms of arithmetic

Abstract:Mathematics is one of the most remarkable human inventions, however we still lack a comprehensive understanding of how the brain computes even simple arithmetic problems. I will present a series of studies in which I used time-resolved measures of behavior and brain activity, combined with machine learning techniques to track, parse and characterize the series of covert processing stages involved in mental calculation, as well as to better understand the neural architecture, dynamics and causal role of the underlying brain networks. I will show how a simple model, which assumes that additions and subtractions are computed by a stepwise displacement on a spatially organized representation of numbers, the 'mental number line', is powerful to explain both behavior performance and brain activity. Next, I will demonstrate with intracranial recordings that, additionally to the traditional parietal and frontal hubs of numerical processing, the ventral-temporal cortex is critically involved in mental calculation and its engagement is both format and modality independent. Finally, I will show that time-resolved decoding can reveal the cascade of unfolding processing stages underlying arithmetic and decision-making at the single-trial level. Overall, this talk will provide insights on how elementary mathematical concepts are implemented in the brain and, more broadly, show how a multimethod approach can help us uncover the mental algorithms of human cognition.