The Processing Characteristics Of Adolescent Emotional Picture Of The Different Potency

A key function of emotion is the preparation for action. Recent studies have shown emotional facilitation of sensory processing in the visual cortex and the late positive component of the event-related-potential (ERP) is enhanced for emotional stimuli. The present study also use event-related potential (ERP) to test whether developmental differences in brain cortical reactivity to emotional stimuli. ERPs were recorded from 48 students with three age stages (13-14years,16-17years,19-20years of age ) . The participants were presented slides of International Affective Picture System (IAPS) posing 60 positive, 60 negative and 60 neutral pictures, which were presented with brief exposure and distinct sequences of six pictures. To concentrate their attention, the subjects were instructed to realize a valence categorization task when pictures offset.The current research uses the P1 component of the event-related brain potential (ERP) as a proximal index of attention allocation to valanced stimuli in earlier emotional processing period , and in the late time interval ,P3 component and a positive slow wave are examined . In all subjects, P1 amplitudes show the difference between emotional stimuli and unemotional ones, and the latencies differ between the positive and negative stimuli at the occipital lobe. Also as same as the result of other emotional pattern, positive, negative and neutral pictures elicited obvious late positive potentials in the picture perception paradigm, which can begin at about 300ms after onset and may be sustained to 900ms. We divided into three windows from 300ms to 440ms, from 440ms to 580ms and then to the end .All the time courses show positive, negative pictures elicited larger amplitudes as compared to neutral pictures in all subjects at central, parietal sites in the both sides of brain. As for the age effect on the emotion perception ,the younger the age ,the greater positivity at occipital lobe for the P1 component and at frontal ,central and parietal sites for P3 and slow wave show the opposite result: the elder group have the greater positibity .The eldest group begin the slow wave in the region of the P3.and not as same as the other younger groups.In summary, brain cortical responses to different valence of emotional pictures show generally same trends of emotional processing in the adolescent group: the enhanced late positive potentials, later in the waveform, that are evoked specifically by emotional pictures. This result approved that the motivational meaning of emotional will modulate to the event-related potential from the early age. And the younger group has the larger P1 amplitudes than the elder one maybe for the reason that more attention to be allocation in the early selective processing. The elder group has the larger later sustained positivity may reflect motivational engagement and a commitment of attentional resources to the picture emotional recognition task. The results also approved that the frontal lobe, the temporal and the parietal lobe are closely correlated with the developmental affect on emotional processing which may be left-hemisphere lateral.