The Active Processing Of Visual Information In Different Central Visual Field Levels: An ERP And ERO Preliminary Study

Purpose: To comparatively study the time domain(event-related potentials,ERP)and frequency domain(event-related oscillation,ERO)features of the different central visual field levels,further to explore the characters and differences of visual information processing with different visual field levels,and expect to provide feasible information to objective evaluation visual field.Method: A visual three-stimulus Oddball paradigm was used in the present study.The respective design of the central circular checkerboard pictures with a visual angle of 5?,10?,20?,or 30? as target stimulus.40 subjects(single eye received stimuli)were instructed to press a button when checkerboard pictures were presented.The behavioral results were recorded and the EEG were collected for each participant.Results: Participants responded more slowly and had lower accuracy with range of visual field increased,and was more apparent for the 30? visual field level than the other three visual field levels.In the study of ERP(1)In temporo-occipital electrodes,the latencies and amplitudes of P1、N1、P2 component evoked standard stimuli did not yield any significant difference in four visual field levels;(2)In temporo-occipital electrodes,the latencies and amplitudes of P1、N1 component evoked target stimuli had no any statistical difference.Target P2 amplitudes gradually increased from the 5? to 20? visual field conditions,while decreased abruptly in the 30? visual field condition,and the amplitudes were larger from the occipital electrodes than that from the temporal sites;(3)In temporo-occipital electrodes,target N2 and visual mismatch negative(vMMN)had a same trend that their amplitudes increased with expansion of the visual field.(4)In central-parietal and parietal electrodes,there was also a tendency that target P3 amplitudes declined but latencies prolonged with increasing visual field ranges;(5)There was a positive relationship between target P3 latency and response time(RT)under four visual field levels;(6)In central-parietal and parietal electrodes,difference P3 latencies prolonged with increasing visual field ranges,but the amplitudes had no statistical difference.In the study of ERO: at the occipital electrodes,although theta band power had no significant differences from the 5? to 20? visual field conditions,there was a tendency that theta power increased with visual field expanded.Conclusions:(1)The early components of ERP cannot reflect change of the magnitude of central visual fields;(2)The middle-late components of ERP can reflect changes in the central visual fields to some extent;(3)theta band existed a tendency of magnitude under different central visual field levels.