EEG-Characteristics in Rest and Parameters of Event Related Potentials when Arithmetic Problems Solving in Primary School Children with Different Levels of Mental Arithmetic Calculation Skills

The EEG/ERP study involved 8–9 year old schoolchildren (24 participants). The participants performed arithmetic tasks in a delayed response verification paradigm: first a problem was presented, then an answer, to which they had to react by pressing a button if it was correct and skip if the answer was incorrect. Differences in the parameters of event related potentials (ERP) were revealed between the group of schoolchildren who made more than 50% of errors (8 people) – children with mental calculation difficulties – and the group of schoolchildren who made less than 20% of errors (13 people) – children with normal formed mental calculation skills. In the group of well-counting schoolchildren (in comparison with poorly counting), when presented with a correct answer, a smaller latency of the P2 component (on the time interval of 140–200 ms) in the central and frontal cortical areas and a larger amplitude of the positive component related to P3 (292–616 ms) with a maximum of differences in the central, parietal, and temporal areas of the right hemisphere were revealed. When an incorrect answer was presented – in the group of well-counting schoolchildren there was a large amplitude of positive components in the wide time interval 272–1232 ms – in the central and parietal cortical areas with a maximum in the right hemisphere. The revealed differences in ERP amplitudes affect both earlier perceptual components (in particular, P2) and later semantic components of ERP, reflecting different stages of information processing and decision making. According to the data of the resting state EEG analysis, the spectral power in θ-, α1- and β1-bands of the EEG, as well as the value of the integral parameter of spatial connectivity calculated from the structural function of the multichannel EEG, was higher in students with mental calculation difficulties than in students with formed mental calculation skills. Taking into account the age dynamics of the analyzed EEG parameters, these differences may characterize a slower maturation of the brain regulatory mechanisms in children with mental calculation difficulties.