| Learning difficulties is a common heterogeneity of learning disabilities. The differentaspects of the previous studies reveal cognitive processing defects of learning difficulties, How-ever, a little studies be involved to the reason of cognitive processing mechanism defects.Nowadays the application of event-related potential technique helps people in cognition study anddiagnosis of brain damage. There are a lot of research in this field from foreign countries, theresults is very rich. The records are relatively simple evoked potentials in the previous ERP studieson Learning difficulties, the main purpose is to observe the specific differences of EEG in learningdisadvantaged groups, and then to make certain whether the sensory perception and processing oflearning difficulties groups have the difficulty or not. Most of them use different types of simplerepetitive stimulation to record ERP data on learning difficulties. All subjects were divided intothe reading difficulties group and control group, did not consider the heterogeneity of the criteriafor the classification. These factors limit the last conclusions.MMN Can be generated in the non-attention in a state of unconsciousness, which don’tneed subjects’ active participation and is unaffected by attention. It’s the brain’s automaticprocessing of sensory information. Take full advantage of higher time resolving capability of ERP,based on learning difficulties children’s cognitive processing mechanism. We try to research MMNof learning difficulties children’s brains cognitive event-related potentials, which is the electroph-ysiological study of higher nervous activity. We choose children who are weak in both Chineseand mathematics fields as an object of the study. Study the brain information automatic processingcharacteristics and cognitive features of children with learning difficulties, and have a deeperstudy to the brain mechanisms of pre-attentional processing on learning difficulties children,Gradually improving the assessment of cognitive function. Objective indicators and theoretical basis is provided to education to help poor children.The research use the cross-modal delayed experimental pattern. Pure tones and picturesstimulate as experimental materials. Two simple green circles were used as visual stimulate andtones of different pitch were used as auditory stimulate. One of tones is the large probability ofstandard stimuli (1000Hz,80%) and the other is a small probability of deviation stimulus (1500Hz,20%). Auditory and visual stimulate were presented sequentially to subjects. The subjects wereinstructed to attend channel in one block and ignore the other with key-responses to the currentattended stimulate by using two hands. The first experiment were instructed to attend visualchannel and ignore the auditory, the second experiment were instructed to attend auditory channeland ignore the visual. Behavioral datas show that hearing is higher than the visual in the correctrate. auditory channel is longer than the visual in distinguishing the standard stimulus response.Deviant stimuli and standard stimuli have audio-visual channel effect. ERP data analysis resultsare as following: Learning difficulty students’ visual MMN latency in the conditions of attention isless than the unattended conditions. The visual MMN amplitude differences were not significantin both attended and unattended condition in learning difficulties and perfect children. Learningdifficulties children’s attention and unattended conditions auditory MMN latency difference wasnot significant. Learning difficulty students’ auditory MMN amplitude is larger than the visualMMN. Children with learning difficulties whose some parts of the MMN amplitude increased,showing that they are slightly better than the outstanding learners in theirs brain automaticprocessing capacity, and some normal cognitive process of pre-attention, suggesting that learningdifficulties children’s early sense perception especially cortical auditory processing is defective. |
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