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@#The question of whether dyslexic children have visual cognitive differences in terms of brain activity as compared to normal children remains unsolved. Here, we aimed to study the neuronal source activity during visual attentional processing reflected in the P300 Event-Related Potential (ERP) component, when being exposed to the different congruency of visual images on dyslexic children by utilizing an ERP. Twelve dyslexic and twelve non-dyslexic children in the range of age 8 to 11 years old took part in this study. They pressed button ‘1’ when they saw a congruence image of the animal in its natural habitat and button ‘2’ for incongruence animal images in non-natural habitat. The source localization of P300 was executed on the grand average waveform by utilising Standardised Low-Resolution Brain Electromagnetic Tomography (sLORETA) algorithm provided by Net Station software. The BA 19 of the left occipital lobe was the most activated during congruence and incongruence images in the dyslexic children. As for the control children, BA 18 and BA 17 of the occipital lobe were activated during congruence and incongruence images, respectively. In sum, there were no differences in source activity areas during both visual images in dyslexic children as compared to the control children, which brings us to a conclusion that the visual attentional activity in dyslexic children used the brain areas that are associated with visual characteristics rather than context differences.
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@#Introduction: Shifted attention can be studied in paired stimuli using different experimental paradigms. Pre-existing literatures showed that children with dyslexia have difficulty in learning. Hence, there might be a relationship between learning difficulty and shifted attention. We investigated shifted attention and topographic distribution of the N200 component using audio–visual paired stimuli in an event-related potential (ERP) study among dyslexic Malay children. Methods: A 128 ERP net designed for children was used for the study. A total of 24 age-matched children were divided into control (n=12) and dyslexic (n=12) groups. A modified audio–visual paired stimuli paradigm was used for the ERP study. Congruent (animal-matched sound) and incongruent (animal-not matched sound) stimuli were used. All participants were instructed to press key ‘1’ and ‘2’ when congruent and incongruent stimuli are presented, respectively. Amplitudes and latencies of the N200 ERP component were analysed at 19 electrode locations in the 10-20 system. A topographic map was analysed for the N200 component for both groups. Results: There was no significant differences in the N200 amplitudes and latencies between children with dyslexia and control children at any sites. The topographic map distribution revealed that the dyslexic group had right frontal and left temporal N200 voltage distribution during the incongruent stimuli. Conclusion: We conclude that Malay children with dyslexia have no difficulties/intact in shifted attention. Moreover, children with dyslexia have diverted left temporal areas during auditory sound attention.
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@#Introduction: Children with dyslexia have disparate visual attention while reading varied structures of grapheme-phoneme that have different congruency. Exploring more related with attention and reading disability, we investigated the visual attention, topographic mapping and correlation of ages of children with dyslexia using ERP study. Methods: A quantitative cross-sectional, non-interventional study was performed with simple randomization to select participants. A total of 24 children were recruited into two groups; control (n=12) and dyslexic (n=12) groups. 128-ERP net was used for ERP experiment. Congruent (true meaningful Malay, 80%) and incongruent (meaningless, 20%) words were used for stimuli. Participants pressed button ‘1' and ‘2' when they saw congruent and incongruent words, respectively. Amplitudes and latencies of P300 ERP component were analysed at 19 electrode sites in 10-20 system. Results: Dyslexics evoked significantly higher P300 amplitude at T6 and shorter P300 latency at Fp1 areas compared with the control group. Moreover, pseudo word stimulations showed a high P300 voltage distribution in the prefrontal and right occipital area in the dyslexics, whereas there was more activation in the bilateral occipito-parietal areas in the controls. Significantly moderate positive correlation was found in the control group at F3, F7 and negative correlation in the dyslexic group at T4 areas for P300 latency. Conclusion: Children with dyslexia have higher visual attention with fronto-central topographic distribution for true Malay words and prefrontal and right occipital areas for pseudo Malay words. Age correlation results indicated that attention is directly related to the brain maturity of children.
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Background: Previous studies from animal models have shown that pre-synapticNMDA receptors (preNMDARs) are present in the cortex, but the role of inhibition mediated bypreNMDARs during epileptogenesis remains unclear. In this study, we wanted to observe thechanges in GABAergic inhibition through preNMDARs in sensory-motor and visual corticalpyramidal neurons after pilocarpine-induced status epilepticus.Methods: Using a pilocarpine-induced epileptic mouse model, sensory-motor and visualcortical slices were prepared, and the whole-cell patch clamp technique was used to recordspontaneous inhibitory post-synaptic currents (sIPSCs).Results: The primary finding was that the mean amplitude of sIPSC from the sensorymotorcortex increased significantly in epileptic mice when the recording pipette contained MK-801 compared to control mice, whereas the mean sIPSC frequency was not significantly different,indicating that post-synaptic mechanisms are involved. However, there was no significant presynapticinhibition through preNMDARs in the acute brain slices from pilocarpine-inducedepileptic mice.Conclusion: In the acute case of epilepsy, a compensatory mechanism of post-synapticinhibition, possibly from ambient GABA, was observed through changes in the amplitude withoutsignificant changes in the frequency of sIPSC compared to control mice. The role of preNMDARmediatedinhibition in epileptogenesis during the chronic condition or in the juvenile stagewarrants further investigation.
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Background: Previous studies have revealed that self-related tasks (items) receive more attention than non-self-related, and that they elicit event-related potential (ERP) components with larger amplitudes. Since personality has been reported as one of the biological correlates influencing these components, as well as our behavioural differences, it is important to examine how it affects our self-consciousness in relation to tasks of varied relevance and the neurological basis. Methods: A total of 33 male and female undergraduate Malaysian medical students of Universiti Sains Malaysia (USM) participated in the study. The participants were divided into two groups, Ambivert (n = 18) and Extravert (n = 15) groups, using the USM personality inventory questionnaire. In the ERP experiment, squares containing standard stimuli of any word other than self and non-self-related nouns (e.g., Bola, Gigi, Anak, etc.; in English: Ball, Teeth, Kids, etc., respectively), those containing self-related pronouns (Saya, Kami or Kita; in English: I, Us or We, respectively), and non-self-related pronouns (Dia, Anda or Mereka; in English: He/She, You or They, respectively), were shown 58%, 21% and 21% of the time, respectively, in a three-stimulus visual oddball paradigm. All words were presented in Bahasa Melayu. The participants were instructed to press 1 for self and 2 for non-self, and ignore standard stimuli. Results: Comparison of both N200 and P300 amplitudes for self-related and non-selfrelated pronouns in the Extravert group revealed significant differences at seven electrode sites, with self-related having larger amplitude at anterior electrodes and less at posterior. This was not seen in the Ambivert group. Conclusion: The present study suggests that self-relevant pronouns are psychologically more important to extraverts than to ambiverts; hence, they have more self-awareness. This may be due to large amount of dopamine in the brains of extraverts, which is more concentrated in the frontal lobe.
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Objective: Literatures on factors influencing performance of the Stroop interference have been elusive on coping styles. Past investigations of coping influence on Stroop test have been indirect and inconclusive due to variability of multidimensional coping models and application of different Stroop test. The concept of constricted versus flexible or broad cognitive style have linked personality and coping styles to Stroop performance. The objective of this study was to determine the associations of coping styles with Stroop resistance towards interference (Stroop RI) and subsequently determine the predictors of Stroop performance. Methods: This was a cross-sectional community research design study with purposive sampling. In this study, the self-administered Brief COPE inventory questionnaires and Stroop Test were performed among 205 undergraduate medical students. Results: Findings revealed that behavioural disengagement (r=-0.361), dysfunctional coping (r=-0.355), self-blame (r = 0.222), and substance abuse (r = -0.173) showed negative correlation and proven strong association with Stroop RI. Further multiple regression analyses identified behavioural disengagement (R2 = 0.13), and dysfunctional coping (R2 = 0.024) as significant predictors for interference. Conclusion: Coping styles have implication on Stroop test exhibited in varied cognitive styles. Integrating coping styles factor on Stroop test has glimpsed the future direction of other neuropsychological assessment batteries on the importance of profiling individualistic baseline norms.