How the human brain discriminates numerosities: A steady-state visual-evoked potentials study

This study aimed at measuring rapidly and objectively human adults' sensitivity to (non)symbolic numerical stimuli, using the steady-state visual-evoked potentials (1) response in the context of repetition suppression (2). It aimed to demonstrate the feasibility of the method and evaluate its potential to tap into the basic numerical representation systems that can be assumed to underlie symbolic and non-symbolic magnitude comparisons. Following a short duration experiment, we observed a large reduction of signal specifically at the 3.5 Hz response, over the occipito-temporo-parietal cortex. This reduction was greater for symbolic than non-symbolic control stimuli. This first observation of repetition suppression to fast periodic stimulation of symbolic and non-symbolic numerosities in the human brain offers a promising tool to study the sensitivity to numerosities in the human brain in adults, but also especially in children.