46. Electrophysiological Correlates of Processing Visual Target Stimuli during a Visual Oddball Paradigm: An Event-Related Potential Study

The aim of the study was to investigate temporal changes of brain to visual stimuli in earthquake-exposed survivors using event-related potentials (ERPs). The present study used ERP to explore whether trauma event and experience had much greater influence on earthquake-exposed survivors than controls, which could provide neuroscience evidences in the psychotherapy for earthquake-exposed survivors. After filling out a series of psychometric questionnaires, 13 earthquake-exposed middle school students and 13 healthy age and sex matched unexposed controls were investigated by using a visual oddball paradigm. One thousand visual stimuli trials were randomly presented with “target” stimuli occurring at a probability of 10 %, “novelty” earthquake-related stimuli 10 %, and “frequent” stimuli 80 %. Participants were asked to respond to “target” stimuli while ignoring other stimuli. Electroencephalogram (EEG) was continually recorded in order to assess P300 responses, an event-related potential (ERP) associated with attention processes. The results showed that the earthquake-exposed group had significantly reduced more P1 and P300 compared to the non earthquake-exposed control group. It indicated that the trauma event and experience had much greater influence on earthquake-exposed survivors than controls.