How does brain percept face expressions: analysis by the method of event related oscillations

HOW DOES BRAIN PERCEPT FACE EXPRESSIONS ? : ANALYSIS BY THEMETHOD OF EVENT RELATED OSCILLATIONSAim of this study is the investigation of brain dynamic responses uponpresentation of pictures with different ?face expressions?. Further, we aim to investigatehow the mood changes affect the dynamic properties of the brain.Event Related Oscillations of ?Neutral, Angry, and Happy? faces in 13 electricalrecordings sites (F3, F4, Cz, C3, C4, T3, T4, T5, T6, P3, P4, O1, O2) were analyzed for 20healthy subjects. Following the recording session, the subjects were asked to express thedegree of their mood on a scale. ERPs were selectively filtered in the 0.5-3.5 Hz (delta),5-8.5 Hz (teta), 9-13 Hz (alpha), 15-24 Hz (beta) frequency ranges.The amplitudes of the alpha responses upon ?angry? face stimulation weresignificantly higher than upon presentation of the ?happy? faces at T5, P3 and O2locations, at F3, Cz and C3, beta responses upon ?angry? face stimulation weresignificantly higher in amplitude compared with the ?happy? face stimulation however,only when selecting stimuli with high mood involvement. The occipital theta (4-7 Hz)and the delta ( 0.5- 3.5 Hz) responses are higher then the frontal responses upon all ?faceexpression? stimulations being independent from their mood.We conclude that the analysis of brain oscillatory responses provide a good basis foranalyzing the influence of emotional information processing in the brain. The resultssupport that angry face stimulations are higher in the amplitude and it can be discussedthat dynamic responses of the brain changes totally when the ?face? stimulation includesemotions.