Exploration of Event-Evoked Oscillatory Activities during a Cognitive Task

Event related potential (ERP) is a kind of cognitive electroencephalogram (EEG) signal, which are directly related with cognitive task and average across EEG. However, the plentiful oscillatory activities evoked by various stimuli as well modulated by different cognitive tasks or behavioral events will be attenuated in the course of average. With respect to every EEG trials caused by the same stimulus, the computation of all trails will be very enormous. In order to explore more significant information about even- evoked oscillatory activities, we introduced the approach of statistical parametric mapping for power-concentrated brain regions and interactivations among them, and applied them to the study of bimodal audio-visual speech cognitive task. The results gave explanations to the power and connectivity change of event-evoked oscillatory activities which matched ERP component in cognitive process. This study may provide a basis for future studies to reveal the underlying neural processes and neural networks associated with specialized cognitive state.