The Automatic Conflict Processing Of Visual Information In Different Visual Acuity Levels:An ERP Preliminary Study

Purpose: By comparing the event-related potential(ERP)component features under visual non-attention status in different visual acuity levels,we would like to further explore the ERP features and specific mechanisms in different visual acuity levels of visual information of automatic conflict processing and expect to provide a theoretical basis and feasibility of electrophysiological techniques for the objective assessment of visual acuity.Method: A cross-modal S1-S2 task under non-attention status was used in the present study,three visual acuity levels were applied and each with four orientations of “E” optotype stimuli(upturned,downturned,leftwards and rightwards).Twenty-two subjects(monocular eye)were asked to look at the center of the front screen without voluntary attention,ignore the size and orientation of the optotype stimuli and simultaneously pay their attention on the radio playing a story.The EEG results of all subjects were collected and analyzed after the experiment.Results:(1)There were no statistical differences in the peak latencies of the three visual acuity levels.(2)In temporo-occipital electrodes,early components of P1,N1 and P2 were evoked by the match and mismatch stimuli of the three visual acuity levels.There was no statistical difference in the component amplitudes of the three visual acuity levels on match conditions.The amplitude of P1 and N1 induced by the supra-threshold mismatch stimuli was the largest and there was no statistical difference between the threshold and sub-threshold conditions,whereas the P2 amplitude showed no significant difference.(3)In frontal and cental electrodes,early components of N1 and P2 were also evoked by the match and mismatch stimuli of the three visual acuity levels.The N1 amplitudes induced by the sub-threshold match and mismatch stimuli were the smallest and there was no statistical difference between the supra-threshold and threshold conditions,whereas the P2 amplitude showed no significant difference.(4)In frontal and cental electrodes,the middle and late components of N2,P3,difference N2 and difference P3 were not evoked by the match stimuli in the three visual acuity levels.(5)In frontal and cental electrodes,the middle and late components of N2 and difference N2 were induced by the supra-threshold and threshold mismatch stimuli,furthermore,N2 and difference N2 amplitudes were larger in threshold than supra-threshold condition.(6)In frontal and cental electrodes,the middle and late components of P3 and difference P3 were only evoked by supra-threshold mismatch stimuli,but no P3 and difference P3 were found in threshold and sub-threshold conditions.Conclusions:(1)The early components of ERP such as P1 of temporo-occipital electrodes and N1 of frontal and cental electrodes could reflect the magnitude change of visual acuity levels in the automatic conflict processing of visual infomation.(2)The middle and late components of ERP such as N2,difference N2,P3 and difference P3 of frontal and cental electrodes could also reflect the magnitude change of visual acuity levels in the automatic conflict processing of visual infomation.