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Fulltext Cortical spreading depression during repeated stimulation - a magnetoencephalographic study

Begum, T., Reza, F., Abdullah, J.M.

ASM Science Journal, 2011;5(2):115-121.
MyJurnal

Reflex epilepsy is usually induced by external stimulation, photosensitive epilepsy being the most common. Epilepsy induced by auditory stimulation is rarely studied. There are no currently published magnetoencephalographic (MEG) studies demonstrating the initiation of epileptic neuronal discharges by repeated auditory stimulations in temporal lobe epilepsy (TLE) patients. We retrospectively studied one TLE patient who underwent a MEG study to localize her epileptic focus. Auditory, somatosensory, visual and motor evoked potential studies were performed during the MEG recording. A single dipole method calculated equivalent current dipoles to localize the epileptic source. The least-squares minimization method was used to obtain the optimal solution with goodness-of-fit of greater than 80%. Periodic lateralized epileptiform discharges (PLEDs) were recorded in the temporal region when repeated auditory stimulations were done. We postulated that neuronal cortical suppression occurred during repeated stimulations which provoked epileptiform discharges (PLEDs) without any physical symptoms or aura. It was concluded that repeated stimulations could facilitate epileptiform discharges in focal area/areas in certain subjects.
Fulltext Insights from the preliminary autocorrelation analysis of low frequency neuronal oscillations during Quran listening

Reza, F., Begum, T., Ahmed, A.L., Omar, H., Muzaimi, M., Abdullah, J.M.

ASM Science Journal, 2012;6(1):39-45.
MyJurnal

The human brain generates different oscillations at different frequencies during various consciousness levels. When these brain waves synchronize with exogenous rhythmic stimulation, the brain experiences strong, yet relaxing emotion that could be involved in the formation of memory. We investigated the character of rhythmic oscillatory dynamics by electroencephalography (EEG) of subjects listening to a short verse of the Holy Quran compared to resting and Arabic news listening. The mean power amplitudes of each frequency band for wavelet-based time-frequency analysis were obtained from 5000 ms of segmented EEG recordings during rest, news and Quran listening conditions. The time series analysis of power from each of three conditions in each frequency band from the grand averaged data was then subjected to autocorrelation study. The results showed significant cyclic overall trends of increasing and decreasing patterns of power in the low frequency brain wave oscillation of different head regions especially global, frontal and temporal sites. These results provided a basis for prediction of the periodicity of the power of the oscillatory brain dynamics of delta and robustly in theta regions which occurred during Quran listening. Despite several limitations, our data offered a plausible scientific basis to the emotional induction during Quran listening that mimics recognized as data from music listening studies. This offered a promising perspective for future studies in translational neurophysiological, cognitive and biofeedback on Quran listening to modify brain behaviour in health and disease.
Influence of education level on design-induced N170 and P300 components of event related potentials in the human brain

Begum T, Reza F, Ahmed I, Abdullah JM

J Integr Neurosci, 2014 Mar;13(1):71-88.
PMID: 24738540 DOI: 10.1142/S0219635214500058

Simple geometric and organic shapes and their arrangement are being used in different neuropsychology tests for the assessment of cognitive function, special memory and also for the therapy purpose in different patient groups. Until now there is no electrophysiological evidence of cognitive function determination for simple geometric, organic shapes and their arrangement. Then the main objective of this study is to know the cortical processing and amplitude, latency of visual induced N170 and P300 event related potential components on different geometric, organic shapes and their arrangement and different educational influence on it, which is worthwhile to know for the early and better treatment for those patient groups. While education influenced on cognitive function by using auditory oddball task, little is known about the influence of education on cognitive function induced by visual attention task in case of the choice of geometric, organic shapes and their arrangements. Using a 128-electrode sensor net, we studied the responses of the choice of the different geometric and organic shapes randomly in experiment 1 and their arrangements in experiment 2 in the high, medium and low education groups. In both experiments, subjects push the button "1" or "2" if like or dislike, respectively. Total 45 healthy subjects (15 in each group) were recruited. ERPs were measured from 11 electrode sites and analyzed to see the evoked N170/N240 and P300 ERP components. There were no differences between like and dislike in amplitudes even in latencies in every stimulus in both experiments. We fixed geometric shapes and organic shapes stimuli only, not like and dislike. Upon the stimulus types, N170 ERP component was found instead of N240, in occipito-temporal (T5, T6, O1 and O2) locations where the amplitude is the highest at O2 location and P300 was distributed in the central (Cz and Pz) locations in both experiments in all groups. In experiment 1, significant low amplitude and non-significant larger latency of the N170 component are found out at O1 location for both stimuli in low education group comparing medium education groups, but in experiment 2, there is no significant difference between stimuli among groups in amplitude and latency. In both experiments, P300 component was found in Cz and Pz locations though the amplitudes are higher at Cz than Pz areas. In experiment 1, medium education group evoked significantly (geometric shape stimuli, P = 0.05; organic shape stimuli, P = 0.02) higher amplitude of P300 component comparing low education group at Cz location. Whereas, there is no significant difference of amplitudes among groups across stimuli in Cz and Pz locations in experiment 2. Latencies have no significant differences in both experiments among groups also, but longer latency are found in low education group at Cz location comparing medium education group, though not significant. We conclude that simple geometric shapes, organic shapes and their arrangements evoked visual N170 component at temporo-occipital areas with right lateralization and P300 ERP component at centro-parietal areas. Significant low amplitude of N170 and P300 ERP components and longer latencies during different shape stimuli in low education group prove that, low education significantly influence on visual cognitive functions in low education group.
Fulltext How Much We Think of Ourselves and How Little We Think of Others: An Investigation of the Neuronal Signature of Self-Consciousness between Different Personality Traits through an Event-Related Potential Study

Hassan AB, Begum T, Reza MF, Yusoff N

Malays J Med Sci, 2016 Nov;23(6):70-82.
PMID: 28090181 MyJurnal DOI: 10.21315/mjms2016.23.6.8

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.
Fulltext Role of Pre-Synaptic NMDA Receptors in the Modulation of Inhibitory Synaptic Transmission in Sensory-Motor and Visual Cortical Pyramidal Neurons in Brain Slices of Young Epileptic Mice

Lah MHC, Reza F, Begum T, Abdullah JM

Malays J Med Sci, 2018 May;25(3):27-39.
PMID: 30899185 MyJurnal DOI: 10.21315/mjms2018.25.3.4

Background: Previous studies from animal models have shown that pre-synaptic NMDA receptors (preNMDARs) are present in the cortex, but the role of inhibition mediated by preNMDARs during epileptogenesis remains unclear. In this study, we wanted to observe the changes in GABAergic inhibition through preNMDARs in sensory-motor and visual cortical pyramidal neurons after pilocarpine-induced status epilepticus.
Methods: Using a pilocarpine-induced epileptic mouse model, sensory-motor and visual cortical slices were prepared, and the whole-cell patch clamp technique was used to record spontaneous inhibitory post-synaptic currents (sIPSCs).
Results: The primary finding was that the mean amplitude of sIPSC from the sensory-motor cortex 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 pre-synaptic inhibition through preNMDARs in the acute brain slices from pilocarpine-induced epileptic mice.
Conclusion: In the acute case of epilepsy, a compensatory mechanism of post-synaptic inhibition, possibly from ambient GABA, was observed through changes in the amplitude without significant changes in the frequency of sIPSC compared to control mice. The role of preNMDAR-mediated inhibition in epileptogenesis during the chronic condition or in the juvenile stage warrants further investigation.
Neural activation patterns and connectivity in visual attention during number and non-number processing: An ERP study using Ishihara pseudoisochromatic plates

Al-Marri F, Reza F, Begum T, Hitam WHW, Jin GK, Xiang J

J Integr Neurosci, 2018 Aug 15;17(3):257-269.
PMID: 30338955 DOI: 10.31083/JIN-170058

Visual cognitive function is important in the construction of executive function in daily life. Perception of visual number form (e.g. Arabic digits) and numerosity (numeric magnitude) is of interest to cognitive neuroscientists. Neural correlates and the functional measurement of number representations are complex events when their semantic categories are assimilated together with concepts of shape and color. Color perception can be processed further to modulate visual cognition. The Ishihara pseudoisochromatic plates are one of the best and most common screening tools for basic red-green color vision testing. However, there has been little study of visual cognitive function assessment using such pseudoisochromatic plates. 25 healthy normal trichromat volunteers were recruited and studied using a 128-sensor net to record event-related electroencephalogram. Subjects were asked to respond by pressing numbered buttons when they saw the number and non-number plates of the Ishihara color vision test. Amplitudes and latencies of N100 and P300 event related potential components were analyzed from 19 electrode sites in the international 10-20 system. A brain topographic map, cortical activation patterns, and Granger causation (effective connectivity) were analyzed from 128 electrode sites. No significant differences between N100 event related potential components for either stimulus indicates early selective attention processing was similar for number and non-number plate stimuli, but non-number plate stimuli evoked significantly higher amplitudes, longer latencies of the P300 event related potential component with a slower reaction time compared to number plate stimuli imply the allocation of attentional load was more in non-number plate processing. A different pattern of the asymmetric scalp voltage map was noticed for P300 components with a higher intensity in the left hemisphere for number plate tasks and higher intensity in the right hemisphere for non-number plate tasks. Asymmetric cortical activation and connectivity patterns revealed that number recognition occurred in the occipital and left frontal areas where as the consequence was limited to the occipital area during the non-number plate processing. Finally, results demonstrated that the visual recognition of numbers dissociates from the recognition of non-numbers at the level of defined neural networks. Number recognition was not only a process of visual perception and attention, but was also related to a higher level of cognitive function, that of language.
Neural activation patterns and connectivity in visual attention during Number and Non-number processing: An ERP study using the Ishihara pseudoisochromatic plates

Al-Marri F, Reza F, Begum T, Hitam WHW, Jin GK, Xiang J

J Integr Neurosci, 2017 Oct 25.
PMID: 29081422 DOI: 10.3233/JIN-170058

Visual cognitive function is important to build up executive function in daily life. Perception of visual Number form (e.g., Arabic digit) and numerosity (magnitude of the Number) is of interest to cognitive neuroscientists. Neural correlates and the functional measurement of Number representations are complex occurrences when their semantic categories are assimilated with other concepts of shape and colour. Colour perception can be processed further to modulate visual cognition. The Ishihara pseudoisochromatic plates are one of the best and most common screening tools for basic red-green colour vision testing. However, there is a lack of study of visual cognitive function assessment using these pseudoisochromatic plates. We recruited 25 healthy normal trichromat volunteers and extended these studies using a 128-sensor net to record event-related EEG. Subjects were asked to respond by pressing Numbered buttons when they saw the Number and Non-number plates of the Ishihara colour vision test. Amplitudes and latencies of N100 and P300 event related potential (ERP) components were analysed from 19 electrode sites in the international 10-20 system. A brain topographic map, cortical activation patterns and Granger causation (effective connectivity) were analysed from 128 electrode sites. No major significant differences between N100 ERP components in either stimulus indicate early selective attention processing was similar for Number and Non-number plate stimuli, but Non-number plate stimuli evoked significantly higher amplitudes, longer latencies of the P300 ERP component with a slower reaction time compared to Number plate stimuli imply the allocation of attentional load was more in Non-number plate processing. A different pattern of asymmetric scalp voltage map was noticed for P300 components with a higher intensity in the left hemisphere for Number plate tasks and higher intensity in the right hemisphere for Non-number plate tasks. Asymmetric cortical activation and connectivity patterns revealed that Number recognition occurred in the occipital and left frontal areas where as the consequence was limited to the occipital area during the Non-number plate processing. Finally, the results displayed that the visual recognition of Numbers dissociates from the recognition of Non-numbers at the level of defined neural networks. Number recognition was not only a process of visual perception and attention, but it was also related to a higher level of cognitive function, that of language.
Fulltext Post-Attentive Integration and Topographic Map Distribution During Audiovisual Processing in Dyslexia: A P300 Event-Related Component Analysis

Ali SA, Begum T, Reza MF, Fadzil NA, Mustafar F

Malays J Med Sci, 2020 Jul;27(4):130-138.
PMID: 32863752 DOI: 10.21315/mjms2020.27.4.12

Background: Research on audiovisual post-attentive integration has been carried out using a variety of experimental paradigms and experimental groups but not yet studied in dyslexia. We investigated post-attentive integration and topographic voltage distribution in children with dyslexia by analysing the P300 event-related potential (ERP) component.
Methods: We used a 128-child ERP net for the ERP experiment. Two types of stimuli were presented as either congruent or incongruent stimuli. Congruent stimuli included a matching auditory sound with an animal image, whereas incongruent stimuli included unmatched animal sounds. A total of 24 age-matched children were recruited in the control (n = 12) and dyslexia (n = 12) groups. Children pressed button '1' or '2' when presented with congruent or incongruent stimuli, respectively. The P300 amplitudes and latencies with topographic voltage distribution were analysed for both groups.
Results: The dyslexia group evoked significantly higher P300 amplitudes at the T4 area than the control group. No significant differences were found in cases of P300 latency. Moreover, the dyslexia group demonstrated a higher intensity of P300 voltage distribution in the right parietal and left occipital areas than the control group.
Conclusion: Post-attentive integration for children with dyslexia is higher and that this integration process implicated the parietal and occipital areas.
Fulltext Trkb-IP3 Pathway Mediating Neuroprotection in Rat Hippocampal Neuronal Cell Culture Following Induction of Kainic Acid

Chong PN, Sangu M, Huat TJ, Reza F, Begum T, Yusoff AAM, et al.

Malays J Med Sci, 2018 Nov;25(6):28-45.
PMID: 30914877 MyJurnal DOI: 10.21315/mjms2018.25.6.4

BACKGROUND: Following brain injury, development of hippocampal sclerosis often led to the temporal lobe epilepsy which is sometimes resistant to common anti-epileptic drugs. Cellular and molecular changes underlying epileptogenesis in animal models were studied, however, the underlying mechanisms of kainic acid (KA) mediated neuronal damage in rat hippocampal neuron cell culture alone has not been elucidated yet.
METHODS: Embryonic day 18 (E-18) rat hippocampus neurons were cultured with poly-L-lysine coated glass coverslips. Following optimisation, KA (0.5 μM), a chemoconvulsant agent, was administered at three different time-points (30, 60 and 90 min) to induce seizure in rat hippocampal neuronal cell culture. We examined cell viability, neurite outgrowth density and immunoreactivity of the hippocampus neuron culture by measuring brain derived neurotrophic factor (BDNF), γ-amino butyric acid A (GABAA) subunit α-1 (GABRA1), tyrosine receptor kinase B (TrkB), and inositol trisphosphate receptor (IP3R/IP3) levels.
RESULTS: The results revealed significantly decreased and increased immunoreactivity changes in TrkB (a BDNF receptor) and IP3R, respectively, at 60 min time point.
CONCLUSION: The current findings suggest that TrkB and IP3 could have a neuroprotective role which could be a potential pharmacological target for anti-epilepsy drugs.