Modulation of neural activities by the complexity of mental arithmetic: An MEG study

Abstract Recent fMRI studies have revealed the involvement of frontal/prefrontal and parietal regions in the mental arithmetic. However it remains unclear how the spatiotemporal characteristics of the neural activities in these regions during arithmetic operations were modulated by the complexity of mental calculations. In this study, we used magnetoencephalography (MEG) to investigate the spatiotemporal cortical activities during mental calculations and their modulation by arithmetic complexity. Increased neural activities in the bilateral frontal/prefrontal and the parietal regions during arithmetic operations were observed in the latencies around 700–900 ms. The activities in the bilateral prefrontal and the left parietal areas in the same latencies were found to be complexity-dependent. Our current results are in agreement with previous fMRI studies and adding further insight into the temporal characteristics of the neural activities in these regions.