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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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@#Introduction: Intracranial brain tumour like meningiomas and glioblastomas are most prevalent tumour. The metastasis to the brain is one of the major issues in the tumours of the central nervous system. The diagnosis of metastatic and primary brain tumour is incomprehensible with standard magnetic resonance imaging (MRI). The magnetic resonance spectroscopy (MRS) is basically performed in standard clinical setting for diagnosing and tracking the brain tumour. Method: It is a retrospective study containing 53 patients with MRS. The patients with metastatic tumour (n=10), glioblastomas (n=8) and meningiomas (n=20) are included in the study. Single voxel technique is applied in the tumour core to determine the metabolites. The tumour N-acetyl aspartate (NAA), Choline (Cho), Creatine (Cr), Lactate, Alanine and lipids were analysed. The ratios of NAA/Cr, Cho/NAA and Cho/Cr were recorded and compared between the three tumours. The metabolites were detected between short echo time (TE) to long echo time (TE) during MRS. Results: There is a sharp fall of NAA peak in metastatic tumour. The resonance of creatine, lactate and alanine is higher in glioblastomas. A high lipid mean value of 3.13(0.17) is seen in metastatic tumour. The ROC curve shows a low NAA/Cr specificity of 46.7%, high sensitivity of 83.3% in Cho/NAA and Cho/Cr ratio. Conclusion: The metabolic profiles of metastatic brain tumour, glioblastomas and meningioma illustrate a divergence in their description that will assist in planning therapeutic and surgical intervention of these tumours.
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Background: Sex is a psychobiological factor that is important in the process of emotion.This study determines the effect of sex on the electropsychological process of various intensities ofemotional arousal.Methods: In the Event-related Potential (ERP) session, electroencephalographic (EEG)data was recorded for 90 participants, 60% of whom were females. The participants responded to30 universal emotional pictures, randomly chosen from the International Affective Picture System(IAPS), which were classified as invoking high, moderate, and low intensity of emotional arousal.Results: From the analysis of variance of two-way mixed design, the interaction betweensex and emotional intensity was observed in the occipital regions (O2), indexed by the amplitudeof P300 and N200 components. Males exhibited higher amplitude of P300 and N200 components(in the occipital region) as responded to high and low emotional arousal stimuli than females.Conclusion: Sex is a fundamental factor that modulates psychological states in reaction toemotional stimuli.
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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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@#The present study discussed functional reorganization and alteration in respond to the slow-growing tumour,hemangiopericytoma in the occipital cortex. Visual evoked field (VEF) and auditory evoked field (AEF) usingmagnetoencephalography (MEG) was used to evaluate the source localization and brain activity. Results of VEF sourcelocalization show a typical brain waves. Brain activity of the occipital lobe demonstrate low activation in the ipsilateralto the tumour. However, result shows the activation on the contralateral hemisphere was high and bigger in activationvolume. AEF result shows an identical source localization and both side of the temporal lobe are activated. This resultsuggests that there is a positive plasticity in auditory cortex and slow-growing tumour can induce functional reorganizationand alteration to the brain.
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@#Neuroplasticity has been subjected to a great deal of research in the last century. Recently, significant emphasis has beenplaced on the global effect of localized plastic changes throughout the central nervous system, and on how these changesintegrate in a pathological context. The present study aimed to demonstrate the functional cortical reorganization beforeand after surgery using magnetoencephalography (MEG) in a participant with brain tumor. Results of Visual EvokedMagnetic Field (VEF) based on functional MEG study revealed significantly different of MEG N100 waveforms before andafter surgery. Larger and additional new locations for visual activation areas after the surgery were found suggestingneuroplasticity. The present study highlight a physiological plasticity in a teenage brain and the alterations regardingneural plasticity and network remodeling described in pathological contexts in higher-order visual association areas.
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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.