Electrophysiological evidence for numerosity processing in infancy

In previous studies we established that similar to adults, 6-9-month-old infants' brain activity showed increased negativity when presented with incorrect solutions to simple arithmetic equations. Moreover, we demonstrated that in adults this frontal reaction was preceded by activity over right parietal areas, which are involved in evaluation of numerical value and its discrepancy from the expected correct solution to the equation. The current article suggests that similar to findings in adults, infants' frontal activity also seems to be preceded by activity in right parietal electrodes, plausibly related to the evaluation of numerosity.