| Purpose: To study different stimulation field's ERP components, further to investigate the character and difference of visual information processing with different visual fields defect, and hope to provide basic information to explore the objective evaluation method of perspective.Method: The study orderly examined the electroencephalic response while 30 subjects with normal visual function were receiving different stimulative fields with the other eye covered. According to the difference of stimulative fields, the study were divided into three parts: (1) The ERP was recorded in the condition of full-field stimulation (13°45′visual field), left and right visual field stimulation with square black-white checkerboard stimulation respectively; (2) The ERP was evoked in the condition of full-field stimulation, lower and upper visual field stimulation with square black-white checkerboard stimulation respectively; (3) The ERP was evoked in the condition of full-field stimulation, quadrant of visual field stimulation with square black-white checkerboard stimulation respectively.Results: (1) The ERP by left/right stimulated field defect: The left/right visual field defec(tL/RVFD)respectively evoked contra-lateral occipito-temporal a lesser amplitude of P1 than ipsi-lateral corresponding the amplitude of P1. Contrary to the early component P1, L/RVFD each produced contra-lateral hemisphere a larger amplitude of N1 and N2 than ipsi-lateral hemisphere its amplitude. In addition, the latency of P1 and N1 over the temporal areas on the same side of VFD obviously prolonged than on the contra-lateral side of VFD. The late ERP components N2 (amplitude) and P3 (amplitude and latency) were similar between LVFD and RVFD;(2) The ERP among upper/ lower stimulated field defect: The early ERP components showed a longer P1 over the occipito-temporal areas and a longer N1 over the extensive encephalic region in lower visual field defect (LoVFD) than in upper visual field defect (UVFD). In addition, the P1 was smaller in UVFD than in LoVFD, but the N1 was similar size between UVFD and LoVFD. The late components showed a longer N2 over the extensive encephalic region and a longer P3 over the centro-parietal region of left hemisphere in UVFD than in LVFD, as well as a smaller N2, but the amplitude of P3 was no difference between the two visual fields;(3) The latency of N1 over temple-parietal area obviously prolonged under the lower left quadrant of visual field defect than the upper right quadrant of visual field defect, but the latency of N2 over frontal-central area was contrary to the component N1; The amplitude of N1was smaller in upper left quadrant of visual field defect than in lower right quadrant of visual field defect; Meanwhile, the amplitude of N2 over parietal region was also much smaller in upper quadrant of visual field defect than lower in quadrant of visual field defect. In addition, the ERP components amplitude and latency in the other quadrant of visual fields were almost similar.Conclusions: These ERP findings showed that: (1) the L/RVFD principally cause contra-lateral occipito-temporal a smaller P1 component, as well as contra-lateral hemisphere a larger N1 and N2 components, but it also indicates that ipsilateral temporal the latency of P1 and N1 remarkably prolonged than contra-lateral its latency; (2) The LoVFD principally causes the early ERP components P1 and N1 prolonged latency but the UVFD mainly evokes the late components N2 and P3 prolonged latency, as well as a smaller P1 and N2. (3) The latency of N1 over temple-parietal area obviously prolonged under the lower left quadrant of visual field defect than the upper right quadrant of visual field defect, but the latency of N2 over frontal-central area is contrary to the component N1, while the amplitude of N1 over temple-parietal area and the N2 over parietal region are smaller under upper quadrant of visual field defect than lower in quadrant of visual field defect.
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