Speaker
Description
There are numerous fMRI studies showing privilege roles of parietal brain in numerical processing. However there are few studies on relationships between temporal dynamics of the parietal brain and performance of the numerical processing. In this study taking advantages of high temporal resolution of EEG, both linear and nonlinear characteristics of the parietal brain during performing an approximation on non-symbolic numerosities (called dot estimation task (DET)) were analyzed in 14 healthy female adolescents. Absolute power (AP) and relative power (RP) at alpha band as linear characteristics and fractal dimension (FD) (showing irregularity and complexity of dynamics) at alpha band as a key nonlinear characteristic were computed during the DET task. The results showed there is not a significant correlation between the dynamical characteristics of the left parietal and the performance of the subjects; whereas in the right parietal AP and FD at alpha band during the DET task showed a strong correlation with the subjects’ performance. The higher alpha FD and AP in the right parietal, the more accurate approximation. A linear regression was performed to quantify the relationship between the approximation performance and the FD and AP values at alpha in the right parietal. Consequently the right parietal plays a more important role in approximation and performing non-symbolic numerosities tasks compared with the left parietal. Furthermore it was shown that during the approximation task, the higher complexity (FD) of the alpha dynamics comes with the higher alpha activity (AP) in the right parietal.
