Study On Neural Mechanism Of Amblyopic Contour Integration Based On EEG

The basis role of contour integration for animal and human visual perception has been widely accepted.The neural mechanism of contour integration is a research hot spot in cognitive neuroscience.Amblyopia refers to an eye disease that seriously impairs children’s visual function due to abnormal visual experience.The researchers believe that amblyopia is mainly a spatial visual defect disease,in which the defect of contour integration ability is one of clinical markers.However,the neural mechanism of contour integration defects of amblyopic patients has not been well explained.Using the former researches’ achievements for reference,this paper designs a novel curvature contour stimulation experiment,using behavioral and event related potential(ERP)techniques to study the difference between amblyopic patients and normal people,in order to explore the neural mechanism of contour integration and solve the neurological mechanism of amblyopic contour integration defects.Through the analysis on the experimental data,we get the following results:(1)When the stimulus presentation time is short,the contour integration of normal group depends more on bottom-up early visual information processing;while the stimulation time is long enough,top-down information feedback will control and improve the contour integration ability.The contour integration ability of amblyopic patients is weaker than normal subjects even when the presentation time is longer,but it is improved compared with the shorter presentation time.(2)Both the behavioral experiments and the EEG experiments in this paper show that,in addition to the influence of local features on contour integration,global features(curvature)also have an impact on contour integration capabilities.Contour integration is clearly influenced by the top-down effect of natural visual experience(by compensation of experience),which is characterized by a improved performance when facing near-straight contour and a semi-circular contour(visual experience group).Although the amblyopic group is not as good as the normal group,probably due to amblyopic patient’s abnormal visual experience during critical periods in visual development,the visual experience group has a higher contour integration ability than the non-visual experience group.(3)The analysis results in time domain,frequency domain and time-frequency combination on EEG data verify the former researcher’s conclusions that contour integration can be accomplished through two-way information interaction between lowlevel and high-level brain regions,i.e.bottom-up feed-forward way and top-down feedback way.Our study find that amblyopic patients also has similar two-way information interaction.Further,the contour integration defect of amblyopic patients is not only in the primary visual area(occipital lobe),but also in the advanced visual area such as the parietal lobe and frontal lobe.In summary,this paper verifies that amblyopic patients have weaker contour integration ability than normal people,and further amblyopic patients have the same but defective two-way information interaction(bottom-up feed-forward and top-down feedback).At the same time,it is found that the top-down ability of visual experience and memory can improve the contour integration ability of amblyopic patients.These results provide a scientific basis and reference solution for bottom-up feed-forward amblyopic training and top-down feedback amblyopic training and treatment.