Nonlinear analysis in cognition process

Cognition process is directly related to the brain functionality and is a dynamically changing system. Nonlinear analysis of EEG signals has been used as a means for studying the dynamical changes in cortical networks. In the course of cognition process, the activity complexity of the neuronal units is continually shifting. This phenomenon can be viewed with the topographic map and nonlinear EEG measures. The surrogate data method was used to show that EEG signals during cognitive activity are nonlinear. Additionally, we employ the compressed spectral array method to show that the γband EEG is closely related to cognitive processes.