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Fulltext MicroRNA profiling reveals unique miRNA signatures in IGF-1 treated embryonic striatal stem cell fate decisions in striatal neurogenesis in vitro

Pati S, Supeno NE, Muthuraju S, Abdul Hadi R, Ghani AR, Idris FM, et al.

Biomed Res Int, 2014;2014:503162.
PMID: 25254208 DOI: 10.1155/2014/503162

The striatum is considered to be the central processing unit of the basal ganglia in locomotor activity and cognitive function of the brain. IGF-1 could act as a control switch for the long-term proliferation and survival of EGF+bFGF-responsive cultured embryonic striatal stem cell (ESSC), while LIF imposes a negative impact on cell proliferation. The IGF-1-treated ESSCs also showed elevated hTERT expression with demonstration of self-renewal and trilineage commitment (astrocytes, oligodendrocytes, and neurons). In order to decipher the underlying regulatory microRNA (miRNA)s in IGF-1/LIF-treated ESSC-derived neurogenesis, we performed in-depth miRNA profiling at 12 days in vitro and analyzed the candidates using the Partek Genome Suite software. The annotated miRNA fingerprints delineated the differential expressions of miR-143, miR-433, and miR-503 specific to IGF-1 treatment. Similarly, the LIF-treated ESSCs demonstrated specific expression of miR-326, miR-181, and miR-22, as they were nonsignificant in IGF-treated ESSCs. To elucidate the possible downstream pathways, we performed in silico mapping of the said miRNAs into ingenuity pathway analysis. Our findings revealed the important mRNA targets of the miRNAs and suggested specific interactomes. The above studies introduced a new genre of miRNAs for ESSC-based neuroregenerative therapeutic applications.

Matched MeSH terms: Visual Cortex/cytology; Visual Cortex/drug effects; Visual Cortex/growth & development*
MRI of optic tract lesions: review and correlation with visual field defects

Fadzli F, Ramli N, Ramli NM

Clin Radiol, 2013 Oct;68(10):e538-51.
PMID: 23932674 DOI: 10.1016/j.crad.2013.05.104

Visual field defects are a conglomerate of patterns of visual impairment derived from diseases affecting the optic nerve as it extends from the globe to the visual cortex. They are complex signs requiring perimetry or visual confrontation for delineation and are associated with diverse aetiologies. This review considers the chiasmatic and post-chiasmatic causes of visual disturbances, with an emphasis on magnetic resonance imaging (MRI) techniques. Newer MRI sequences are considered, such as diffusion-tensor imaging. MRI images are correlated with perimetric findings in order to demonstrate localization of lesions in the visual pathway. This may serve as a valuable reference tool to clinicians and radiologists in the early diagnostic process of differentiating causes of various visual field defects in daily practice.

Matched MeSH terms: Visual Cortex/pathology
A generalized subspace approach for estimating visual evoked potentials

Kamel N, Yusoff MZ

Annu Int Conf IEEE Eng Med Biol Soc, 2008;2008:5208-11.
PMID: 19163891 DOI: 10.1109/IEMBS.2008.4650388

A "single-trial" signal subspace approach for extracting visual evoked potential (VEP) from the ongoing 'colored' electroencephalogram (EEG) noise is proposed. The algorithm applies the generalized eigendecomposition on the covariance matrices of the VEP and noise to transform them jointly into diagonal matrices in order to avoid a pre-whitening stage. The proposed generalized subspace approach (GSA) decomposes the corrupted VEP space into a signal subspace and noise subspace. Enhancement is achieved by removing the noise subspace and estimating the clean VEPs only from the signal subspace. The validity and effectiveness of the proposed GSA scheme in estimating the latencies of P100's (used in objective assessment of visual pathways) are evaluated using real data collected from Selayang Hospital in Kuala Lumpur. The performance of GSA is compared with the recently proposed single-trial technique called the Third Order Correlation (TOC).

Matched MeSH terms: Visual Cortex/physiology*
Fulltext IGF-1 acts as controlling switch for long-term proliferation and maintenance of EGF/FGF-responsive striatal neural stem cells

Supeno NE, Pati S, Hadi RA, Ghani AR, Mustafa Z, Abdullah JM, et al.

Int J Med Sci, 2013;10(5):522-31.
PMID: 23532711 DOI: 10.7150/ijms.5325

Long-term maintenance of neural stem cells in vitro is crucial for their stage specific roles in neurogenesis. To have an in-depth understanding of optimal conditional microenvironmental niche for long-term maintenance of neural stem cells (NSCs), we imposed different combinatorial treatment of growth factors to EGF/FGF-responsive cells. We hypothesized, that IGF-1-treatment can provide an optimal niche for long-term maintenance and proliferation of EGF/FGF-responsive NSCs.

Matched MeSH terms: Visual Cortex/cytology; Visual Cortex/growth & development*
Fulltext Functional MRI characteristics in visual cortex (BA 17, 18 and 19) corresponding to the visual field of normal, glaucoma suspect (GS) and primary open angle glaucoma (PCOG) patients

Nurul Hanim Nasaruddin, Nurul Hanim Nasaruddin, Ahmad NazlimYusoff, Sharanjeet, Kaur

Jurnal Sains Kesihatan Malaysia, 2017;15(1):27-32.
MyJurnal

The purpose of this study was to characterize, differentiate and correlate visual field and brain activation in visual cortex
for normal, glaucoma suspect (GS) and primary open angle glaucoma (POAG) participants using Standard Automated
Perimetry (SAP) and functional Magnetic Resonance Imaging (fMRI) respectively. The fMRI scans and SAP test were both
carried out in Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM). Two types of black-and-white checkerboard
pattern were displayed to the participants during the fMRI scans. The fMRI data were analyzed using WFU pickatlas
toolbox targeting visual cortex area. The results showed that there was no significant difference in number of activated
voxel between the three groups in visual cortex (BA 17, 18 and 19) while viewing all the given stimuli (p > 0.05). The
pattern standard deviation (PSD) of SAP for visual field also revealed no significant differences (p > 0.05) in all groups of
participants. However, negative correlation between PSD and fMRI activation was observed. The PSD values increased with
a decrease in fMRI activation. With reference to visual field analysis, the results suggest that glaucomatous neuropathy of
POAG patients has led to a gradual decrease in visual cortex activation and a gradual increase in PSD.

Matched MeSH terms: Visual Cortex
EEG based brain source localization comparison of sLORETA and eLORETA

Jatoi MA, Kamel N, Malik AS, Faye I

Australas Phys Eng Sci Med, 2014 Dec;37(4):713-21.
PMID: 25359588 DOI: 10.1007/s13246-014-0308-3

Human brain generates electromagnetic signals during certain activation inside the brain. The localization of the active sources which are responsible for such activation is termed as brain source localization. This process of source estimation with the help of EEG which is also known as EEG inverse problem is helpful to understand physiological, pathological, mental, functional abnormalities and cognitive behaviour of the brain. This understanding leads for the specification for diagnoses of various brain disorders such as epilepsy and tumour. Different approaches are devised to exactly localize the active sources with minimum localization error, less complexity and more validation which include minimum norm, low resolution brain electromagnetic tomography (LORETA), standardized LORETA, exact LORETA, Multiple Signal classifier, focal under determined system solution etc. This paper discusses and compares the ability of localizing the sources for two low resolution methods i.e., sLORETA and eLORETA respectively. The ERP data with visual stimulus is used for comparison at four different time instants for both methods (sLORETA and eLORETA) and then corresponding activation in terms of scalp map, slice view and cortex map is discussed.

Matched MeSH terms: Visual Cortex/physiology*
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.

Matched MeSH terms: Visual Cortex