Displaying publications 1 - 20 of 41 in total

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  1. EEG features of focal malformations of cortical development
    Raymond AA, Fish DR
    J Clin Neurophysiol, 1996 Nov;13(6):495-506.
    PMID: 8978621
    Recent advances in neuroimaging have allowed the detection and characterization of focal malformations of cortical developmental in a significant proportion of patients with epilepsy, many of whom were previously labelled as cryptogenic, allowing a better description of the associated electroencephalogram (EEG) features. Alpha activity is usually preserved, although superficial gyral abnormalities are often associated with overlying localized polymorphic delta activity, and occasionally abnormal fast activity. Most affected patients with epilepsy show interictal spikes. These are often broadly concordant with the structural abnormality but may show a wider anatomic distribution and be multifocal, or occasionally appear only in anatomically distant sites. In many patients the spikes are frequent and sometimes they occur continuously or in long trains. EEG findings are often stable over time, but some patients only show the development of slow wave changes or interictal spikes when followed serially for several years. A small proportion of patients with focal malformations of cortical development have EEG features mimicking idiopathic generalized epilepsy, and occasionally patients exhibit continuous generalized spike and slow wave activity in sleep. Electrocorticography studies confirm the often widespread nature of interictal spiking, but may also show highly epileptogenic patterns recorded directly from dysplastic cortex. The intrinsic epileptogenicity of areas of cortical developmental abnormalities has also been demonstrated by chronic intracranial studies and in vitro recordings of slices obtained from resected human dysplastic cortex. In this regard such developmental abnormalities are fundamentally different from acquired lesions such as tumors/vascular anomalies that usually exert their effects through changes in adjacent cortex.
    Matched MeSH terms: Cerebral Cortex/abnormalities*; Cerebral Cortex/physiopathology; Cerebral Cortex/surgery
  2. Fulltext An Emotion Assessment of Stroke Patients by Using Bispectrum Features of EEG Signals
    Yean CW, Wan Ahmad WK, Mustafa WA, Murugappan M, Rajamanickam Y, Adom AH, et al.
    Brain Sci, 2020 Sep 25;10(10).
    PMID: 32992930 DOI: 10.3390/brainsci10100672
    Emotion assessment in stroke patients gives meaningful information to physiotherapists to identify the appropriate method for treatment. This study was aimed to classify the emotions of stroke patients by applying bispectrum features in electroencephalogram (EEG) signals. EEG signals from three groups of subjects, namely stroke patients with left brain damage (LBD), right brain damage (RBD), and normal control (NC), were analyzed for six different emotional states. The estimated bispectrum mapped in the contour plots show the different appearance of nonlinearity in the EEG signals for different emotional states. Bispectrum features were extracted from the alpha (8-13) Hz, beta (13-30) Hz and gamma (30-49) Hz bands, respectively. The k-nearest neighbor (KNN) and probabilistic neural network (PNN) classifiers were used to classify the six emotions in LBD, RBD and NC. The bispectrum features showed statistical significance for all three groups. The beta frequency band was the best performing EEG frequency-sub band for emotion classification. The combination of alpha to gamma bands provides the highest classification accuracy in both KNN and PNN classifiers. Sadness emotion records the highest classification, which was 65.37% in LBD, 71.48% in RBD and 75.56% in NC groups.
    Matched MeSH terms: Cerebral Cortex
  3. Ultra-slow oscillations in cortical networks in vitro
    Mok SY, Nadasdy Z, Lim YM, Goh SY
    Neuroscience, 2012 Mar 29;206:17-24.
    PMID: 22266346 DOI: 10.1016/j.neuroscience.2012.01.009
    An ultra-slow oscillation (<0.01 Hz) in the network-wide activity of dissociated cortical networks is described in this article. This slow rhythm is characterized by the recurrence of clusters of large synchronized bursts of activity lasting approximately 1-3 min, separated by an almost equivalent interval of relatively smaller bursts. Such rhythmic activity was detected in cultures starting from the fourth week in vitro. Our analysis revealed that the propagation motifs of constituent bursts were strongly conserved across multiple oscillation cycles, and these motifs were more consistent at the electrode level compared with the neuronal level.
    Matched MeSH terms: Cerebral Cortex/physiology*
  4. [Observation of a photosensitive syndrome in Macaca nemestrina (author's transl)]
    Balzamo E
    Rev Electroencephalogr Neurophysiol Clin, 1981 Nov;11(2):289-93.
    PMID: 7323374
    Out of a group of 12 M. nemestrina (originating from Malaysia), 9 adults had shown clinical signs induced by ILS at 25 c/sec. Six of them (3 males, 3 females) were very photosensitive; however, only 2 presented eyelid and/or head jerks after the end of ILS (level 4), but never a generalized seizure. Tactile periorbital stimuli favoured myoclonus. In all but the two of level 4, the intensity of clinical signs varied from one day to the next. In all implanted adult macaques, spontaneous paroxysmal EEG activities were seen during slow sleep in mostly anterior areas, but also during waking and REM sleep in some of them; however, their occurrence depended upon the individual and were not in all cases related to their level of photosensitivity. During ILS, paroxysmal discharges (spikes and waves and/or polyspikes and waves), isolated or in bursts at 3-4/sec were bilateral and symmetrical. They started in fronto-rolandic regions, then became generalized. This observation constitutes a new fact since the discovery, in 1966, of the photomyoclonic syndrome of Papio papio, Macaca nemestrina being another species of subhuman primates with a marked predisposition to photosensitive epilepsy.
    Matched MeSH terms: Cerebral Cortex/physiopathology
  5. Fulltext Revision of the carnivorous snail genus Discartemon Pfeiffer, 1856, with description of twelve new species (Pulmonata, Streptaxidae)
    Siriboon T, Sutcharit C, Naggs F, Rowson B, Panha S
    Zookeys, 2014.
    PMID: 24843260 DOI: 10.3897/zookeys.401.7075
    Twelve new species of the streptaxid snail genus Discartemon Pfeiffer, 1856 are described from southern Thailand and western Malaysia, D. afthonodontia sp. n., D. circulus sp. n., D. deprima sp. n., D. discadentus sp. n., D. discamaximus sp. n., D. expandus sp. n., D. flavacandida sp. n., D. kotanensis sp. n., and D. megalostraka sp. n. from southern Thailand, as well as D. conicus sp. n., D. epipedis sp. n. and D. triancus sp. n. from western Malaysia. All 15 previously described species are revised and commented upon based on examined material. Streptaxis paradiscus Möllendorff, 1900 is considered a junior subjective synonym of the type species D. discus (Pfeiffer, 1853). Details of the genital anatomy of twelve species, and the radula and pallial system, are provided for the first time. An identification key is provided.
    Matched MeSH terms: Cerebral Cortex
  6. 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.

    Matched MeSH terms: Cerebral Cortex
  7. Associable representations as field of influence for dynamic cognitive processes
    Cacha LA, Poznanski RR
    J Integr Neurosci, 2011 Dec;10(4):423-37.
    PMID: 22262534
    In earlier models, synaptic plasticity forms the basis for cellular signaling underlying learning and memory. However, synaptic computation of learning and memory in the brain remains controversial. In this paper, we discuss ways in which synaptic plasticity remodels subcellular networks by deflecting trajectories in neuronal state-space as regulating patterns for the synthesis of dynamic continuity that form cognitive networks of associable representations through endogenous dendritic coding to consolidate memory.
    Matched MeSH terms: Cerebral Cortex/cytology*; Cerebral Cortex/physiology
  8. Fulltext Antioxidant and Neuroprotective Effects Induced by Cannabidiol and Cannabigerol in Rat CTX-TNA2 Astrocytes and Isolated Cortexes
    di Giacomo V, Chiavaroli A, Recinella L, Orlando G, Cataldi A, Rapino M, et al.
    Int J Mol Sci, 2020 05 18;21(10).
    PMID: 32443623 DOI: 10.3390/ijms21103575
    Cannabidiol (CBD) and cannabigerol (CBG) are Cannabis sativa terpenophenols. Although CBD's effectiveness against neurological diseases has already been demonstrated, nothing is known about CBG. Therefore, a comparison of the effects of these compounds was performed in two experimental models mimicking the oxidative stress and neurotoxicity occurring in neurological diseases. Rat astrocytes were exposed to hydrogen peroxide and cell viability, reactive oxygen species production and apoptosis occurrence were investigated. Cortexes were exposed to K+ 60 mM depolarizing stimulus and serotonin (5-HT) turnover, 3-hydroxykinurenine and kynurenic acid levels were measured. A proteomic analysis and bioinformatics and docking studies were performed. Both compounds exerted antioxidant effects in astrocytes and restored the cortex level of 5-HT depleted by neurotoxic stimuli, whereas sole CBD restored the basal levels of 3-hydroxykinurenine and kynurenic acid. CBG was less effective than CBD in restoring the levels of proteins involved in neurotransmitter exocytosis. Docking analyses predicted the inhibitory effects of these compounds towards the neurokinin B receptor. Conclusion: The results in the in vitro system suggest brain non-neuronal cells as a target in the treatment of oxidative conditions, whereas findings in the ex vivo system and docking analyses imply the potential roles of CBD and CBG as neuroprotective agents.
    Matched MeSH terms: Cerebral Cortex/metabolism*; Cerebral Cortex/physiology
  9. The effects of chronic mitragynine (Kratom) exposure on the EEG in rats
    Suhaimi FW, Hassan Z, Mansor SM, Müller CP
    Neurosci Lett, 2021 02 06;745:135632.
    PMID: 33444671 DOI: 10.1016/j.neulet.2021.135632
    Mitragynine is the main alkaloid isolated from the leaves of Mitragyna speciosa Korth (Kratom). Kratom has been widely used to relieve pain and opioid withdrawal symptoms in humans but may also cause memory deficits. Here we investigated the changes in brain electroencephalogram (EEG) activity after acute and chronic exposure to mitragynine in freely moving rats. Vehicle, morphine (5 mg/kg) or mitragynine (1, 5 and 10 mg/kg) were administered for 28 days, and EEG activity was repeatedly recorded from the frontal cortex, neocortex and hippocampus. Repeated exposure to mitragynine increased delta, but decreased alpha powers in both cortical regions. It further decreased delta power in the hippocampus. These findings suggest that acute and chronic mitragynine can have profound effects on EEG activity, which may underlie effects on behavioral activity and cognition, particularly learning and memory function.
    Matched MeSH terms: Cerebral Cortex/drug effects*; Cerebral Cortex/physiology*
  10. Fulltext Selection of Mother Wavelet Functions for Multi-Channel EEG Signal Analysis during a Working Memory Task
    Al-Qazzaz NK, Bin Mohd Ali SH, Ahmad SA, Islam MS, Escudero J
    Sensors (Basel), 2015;15(11):29015-35.
    PMID: 26593918 DOI: 10.3390/s151129015
    We performed a comparative study to select the efficient mother wavelet (MWT) basis functions that optimally represent the signal characteristics of the electrical activity of the human brain during a working memory (WM) task recorded through electro-encephalography (EEG). Nineteen EEG electrodes were placed on the scalp following the 10-20 system. These electrodes were then grouped into five recording regions corresponding to the scalp area of the cerebral cortex. Sixty-second WM task data were recorded from ten control subjects. Forty-five MWT basis functions from orthogonal families were investigated. These functions included Daubechies (db1-db20), Symlets (sym1-sym20), and Coiflets (coif1-coif5). Using ANOVA, we determined the MWT basis functions with the most significant differences in the ability of the five scalp regions to maximize their cross-correlation with the EEG signals. The best results were obtained using "sym9" across the five scalp regions. Therefore, the most compatible MWT with the EEG signals should be selected to achieve wavelet denoising, decomposition, reconstruction, and sub-band feature extraction. This study provides a reference of the selection of efficient MWT basis functions.
    Matched MeSH terms: Cerebral Cortex
  11. Fulltext Schizencephaly: psychosis, a rare manifestation
    Aloysius, A., Seed, H.F., Thong, K.S.
    Malaysian Journal of Psychiatry, 2017;26(2):0-0.
    MyJurnal
    Schizencephaly is an uncommon congenital malformation of the central
    nervous system which affects the development of the cerebral cortex. It is
    defined as the gray matter lined filled cleft with cerebrospinal fluid that
    extends from the pial surface to the ventricle. There exists a paucity in
    scientific literature regarding the association between schizencephaly and
    psychosis. We report a case of a 36-year-old male, presented with worsening
    crisis of aggression, disorganized behavior and auditory hallucinations over
    20 years. CT brain scan revealed unilateral left open lip schizencephaly, a
    finding during his recent admission to the psychiatry ward.
    Matched MeSH terms: Cerebral Cortex
  12. Fulltext Exploring Cortical Plasticity and Oscillatory Brain Dynamics via Transcranial Magnetic Stimulation and Resting-State Electroencephalogram
    Noh NA
    Malays J Med Sci, 2016 Jul;23(4):5-16.
    PMID: 27660540 MyJurnal DOI: 10.21315/mjms2016.23.4.2
    Transcranial magnetic stimulation (TMS) is a non-invasive, non-pharmacological technique that is able to modulate cortical activity beyond the stimulation period. The residual aftereffects are akin to the plasticity mechanism of the brain and suggest the potential use of TMS for therapy. For years, TMS has been shown to transiently improve symptoms of neuropsychiatric disorders, but the underlying neural correlates remain elusive. Recently, there is evidence that altered connectivity of brain network dynamics is the mechanism underlying symptoms of various neuropsychiatric illnesses. By combining TMS and electroencephalography (EEG), the functional connectivity patterns among brain regions, and the causal link between function or behaviour and a specific brain region can be determined. Nonetheless, the brain network connectivity are highly complex and involve the dynamics interplay among multitude of brain regions. In this review article, we present previous TMS-EEG co-registration studies, which explore the functional connectivity patterns of human cerebral cortex. We argue the possibilities of neural correlates of long-term potentiation/depression (LTP-/LTD)-like mechanisms of synaptic plasticity that drive the TMS aftereffects as shown by the dissociation between EEG and motor evoked potentials (MEP) cortical output. Here, we also explore alternative explanations that drive the EEG oscillatory modulations post TMS. The precise knowledge of the neurophysiological mechanisms underlying TMS will help characterise disturbances in oscillatory patterns, and the altered functional connectivity in neuropsychiatric illnesses.
    Matched MeSH terms: Cerebral Cortex
  13. Fulltext The Effect of 4-hydroxybenzaldehyde on the γ-aminobutyric Acid Type A Receptor
    Zhang J, Mohamad H, Wong JH, Bilal M, Ismail AHB, Lloyd AJ, et al.
    Malays J Med Sci, 2017 Mar;24(2):94-99.
    PMID: 28894409 DOI: 10.21315/mjms2017.24.2.12
    The α1β2γ2 subtype of GABAA receptors is the most commonly found GABAA receptor subtype in the mammalian cortex and hippocampus. It is expressed heterologously in the Xenopus laevis oocyte as a α1β2γ2S/L subtype for application as an in vitro model for the screening of compounds that modulate receptor activities. In fact, 4-hydroxybenzaldehyde (4-HB) has been identified as one of the major components in Dendrocalamus asper bamboo shoots in our previous study, and the current study showed that at 101.7 μM, 4-HB significantly reduced the GABA-induced chloride current of GABAA receptors expressed on Xenopus oocytes, indicating a possible GABAergic antagonistic effect at high concentrations.
    Matched MeSH terms: Cerebral Cortex
  14. 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.
    Matched MeSH terms: Cerebral Cortex/physiology*
  15. Functional brain imaging of walking while talking - An fNIRS study
    Metzger FG, Ehlis AC, Haeussinger FB, Schneeweiss P, Hudak J, Fallgatter AJ, et al.
    Neuroscience, 2017 02 20;343:85-93.
    PMID: 27915210 DOI: 10.1016/j.neuroscience.2016.11.032
    Since functional imaging of whole body movements is not feasible with functional magnetic resonance imaging (fMRI), the present study presents in vivo functional near-infrared spectroscopy (fNIRS) as a suitable technique to measure body movement effects on fronto-temporo-parietal cortical activation in single- and dual-task paradigms. Previous fNIRS applications in studies addressing whole body movements were typically limited to the assessment of prefrontal brain areas. The current study investigated brain activation in the frontal, temporal and parietal cortex of both hemispheres using functional near-infrared spectroscopy (fNIRS) with two large 4×4 probe-sets with 24 channels each during single and dual gait tasks. 12 young healthy adults were measured using fNIRS walking on a treadmill: the participants performed two single-task (ST) paradigms (walking at different speeds, i.e. 3 and 5km/h) and a dual task (DT) paradigm where a verbal fluency task (VFT) had to be executed while walking at 3km/h. The results show an increase of activation in Broca's area during the more advanced conditions (ST 5km/h vs. ST 3km/h, DT vs. ST 3km/h, DT vs. 5km/h), while the corresponding area on the right hemisphere was also activated. DT paradigms including a cognitive task in conjunction with whole body movements elicit wide-spread cortical activation patterns across fronto-temporo-parietal areas. An elaborate assessment of these activation patterns requires more extensive fNIRS assessments than the traditional prefrontal investigations, e.g. as performed with portable fNIRS devices.
    Matched MeSH terms: Cerebral Cortex/physiology*
  16. Fulltext Clinical characteristics and risk factors for a complex first febrile convulsion
    Ling SG
    Singapore Med J, 2001 Jun;42(6):264-7.
    PMID: 11547964
    To determine the frequency of complex features in febrile convulsion, association of complex febrile convulsion with neurological findings and risk factors associated with complex febrile convulsion.
    Matched MeSH terms: Cerebral Cortex/pathology*
  17. Heterogeneity in brain functional changes of cognitive processing in ADHD across age: A systematic review of task-based fMRI studies
    Yap KH, Abdul Manan H, Sharip S
    Behav Brain Res, 2021 01 15;397:112888.
    PMID: 32882284 DOI: 10.1016/j.bbr.2020.112888
    This review aims to establish the cognitive processing of patients with attention-deficit hyperactive disorder (ADHD) across age. Functional magnetic resonance imaging (fMRI) studies on children and adult populations were conducted, thus delineating deficits that could have been maintained and ameliorated across age. This allowed for the examination of the correlation between patterns of brain activation and the corresponding development of functional heterogeneity in ADHD. A systematic literature search of fMRI studies on ADHD was conducted using the PubMed and Scopus electronic databases based on PRISMA guidelines. References and citations were verified in Scopus database. The present study has identified 14 studies on children, 16 studies on adults, and one study on both populations of ADHD consisting of 1371 participants. Functional heterogeneity is present in ADHD across age, which can manifest either as different brain activation patterns, intra-subject variability, or both. This is shown in the increased role of the frontal regions and the specialized network in adults with ADHD from inefficient non-specific activation in childhood. Functional heterogeneity may manifest when delayed maturation is insufficient to normalize frontal lobe functions.
    Matched MeSH terms: Cerebral Cortex/growth & development; Cerebral Cortex/physiopathology*
  18. Fulltext Negative correlation of cortical thickness with the severity and duration of abdominal pain in Asian women with irritable bowel syndrome
    Chua CS, Bai CH, Shiao CY, Hsu CY, Cheng CW, Yang KC, et al.
    PLoS One, 2017;12(8):e0183960.
    PMID: 28859146 DOI: 10.1371/journal.pone.0183960
    BACKGROUND & AIMS: Irritable bowel syndrome (IBS) manifests as chronic abdominal pain. One pathophysiological theory states that the brain-gut axis is responsible for pain control in the intestine. Although several studies have discussed the structural changes in the brain of IBS patients, most of these studies have been conducted in Western populations. Different cultures and sexes experience different pain sensations and have different pain responses. Accordingly, we aimed to identify the specific changes in the cortical thickness of Asian women with IBS and to compare these data to those of non-Asian women with IBS.

    METHODS: Thirty Asian female IBS patients (IBS group) and 39 healthy individuals (control group) were included in this study. Brain structural magnetic resonance imaging was performed. We used FreeSurfer to analyze the differences in the cortical thickness and their correlations with patient characteristics.

    RESULTS: The left cuneus, left rostral middle frontal cortex, left supramarginal cortex, right caudal anterior cingulate cortex, and bilateral insula exhibited cortical thinning in the IBS group compared with those in the controls. Furthermore, the brain cortical thickness correlated negatively the severity as well as duration of abdominal pain.

    CONCLUSIONS: Some of our findings differ from those of Western studies. In our study, all of the significant brain regions in the IBS group exhibited cortical thinning compared with those in the controls. The differences in cortical thickness between the IBS patients and controls may provide useful information to facilitate regulating abdominal pain in IBS patients. These findings offer insights into the association of different cultures and sexes with differences in cortical thinning in patients with IBS.

    Matched MeSH terms: Cerebral Cortex/pathology*; Cerebral Cortex/physiopathology
  19. Quantitative autoradiographic studies of relaxin binding in rat atria, uterus and cerebral cortex: characterization and effects of oestrogen treatment
    Tan YY, Wade JD, Tregear GW, Summers RJ
    Br J Pharmacol, 1999 May;127(1):91-8.
    PMID: 10369460
    The binding characteristics of the relaxin receptor in rat atria, uterus and cortex were studied using a [33P]-labelled human gene 2 relaxin (B33) and quantitative receptor autoradiography. The binding kinetics of [33P]-human gene 2 relaxin (B33) were investigated in slide-mounted rat atrial sections. The binding achieved equilibrium after 60 min incubation at room temperature (23+/-1 degrees C) and dissociated slowly. The association and dissociation rate constants were 4.31+/-0.34x10(8) M(-1) x min(-1) and 1.55+/-0.38x10(-3) min(-1) respectively. Thus, the kinetic dissociation constant was 3.46+/-0.59 pM. Binding was saturable to a single population of non-interacting sites throughout atria, in uterine myometrium and the 5th layer of cerebral cortex. The binding affinities (pK(D)) of [33P]-human gene 2 relaxin (B33) were 8.92+/-0.09 in atrial myocardium and 8.79+/-0.04 in cerebral cortex of male rats, and 8.79+/-0.10 in uterine myometrium. Receptor densities in the cerebral cortex and atria were higher than in uterine myometrium, indicating that relaxin also has important roles in non-reproductive tissues. In male rats, treatment with 17beta-oestradiol (20 microg in 0.1 ml sesame oil s.c., 18-24 h) significantly decreased the density of relaxin receptors in atria and cerebral cortex. Identical treatment in female rats had no significant effect in atria and cerebral cortex, but it significantly increased the density of relaxin receptors in uterine myometrium. Relaxin binding was competitively displaced by porcine and rat native relaxins. Porcine native relaxin binds to the relaxin receptor in male rat atria (8.90+/-0.02), and cerebral cortex (8.90+/-0.03) and uterine myometrium (8.89+/-0.03) with affinities not significantly different from human gene 2 (B33) relaxin. Nevertheless, rat relaxin binds to the receptors with affinities (8.35+/-0.09 in atria, 8.22+/-0.07 in cerebral cortex and 8.48+/-0.06 in uterine myometrium) significantly less than human gene 2 (B33) and porcine relaxins. Quantitative receptor autoradiography is the method of choice for measurement of affinities and densities of relaxin receptor in atria, uterine myometrium and cerebral cortex. High densities were found in all these tissues. 17beta-oestradiol treatment produced complex effects where it increased the densities of relaxin receptors in uterus but decreased those in atria and cerebral cortex of the male rats, and had no effect on the atria and cerebral cortex of the female rats.
    Matched MeSH terms: Cerebral Cortex/drug effects; Cerebral Cortex/metabolism*
  20. Fulltext Effect of tualang honey against KA-induced oxidative stress and neurodegeneration in the cortex of rats
    Mohd Sairazi NS, K N S S, Asari MA, Mummedy S, Muzaimi M, Sulaiman SA
    BMC Complement Altern Med, 2017 Jan 09;17(1):31.
    PMID: 28068984 DOI: 10.1186/s12906-016-1534-x
    Administration of KA on rodents has resulted in seizures, behavioral changes, oxidative stress, and neuronal degeneration on selective population of neurons in the brain. The present study was undertaken to investigate the extent of neuroprotective effect conferred by Malaysian Tualang Honey (TH), an antioxidant agent, in the cerebral cortex of rats against KA-induced oxidative stress and neurodegeneration in an animal model of KA-induced excitotoxicity.
    Matched MeSH terms: Cerebral Cortex/drug effects; Cerebral Cortex/metabolism*
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