Effects of l-dopa methyl ester on visual cortex injury induced by amblyopia and its underlying mechanism

2012 ◽  
Vol 508 (2) ◽  
pp. 95-100 ◽  
Author(s):  
Rong Li ◽  
Tao Liang ◽  
Yongwen Li ◽  
Weizhe Jiang ◽  
Renbin Huang
Keyword(s):  
Visual Cortex ◽  
Methyl Ester ◽  
Underlying Mechanism

FDG-PET Scanning Shows Distributed Changes in Cortical Activity Associated with Visual Hallucinations in Eye Disease

2019 ◽  
Vol 19 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Lütfü Hanoglu ◽  
Sultan Yildiz ◽  
Tansel Cakir ◽  
Taha Hanoglu ◽  
Burak Yulug
Keyword(s):  
Visual Cortex ◽  
Fdg Pet ◽  
Underlying Mechanism ◽  
Posterior Cingulate Cortex ◽  
Eye Disease ◽  
Visual Hallucinations ◽  
Charles Bonnet Syndrome ◽  
Pet Scanning ◽  
Inferior Parietal Cortex ◽  
Visual Deafferentation

Background and Objective: Charles Bonnet Syndrome (CBS) has been defined as complex visual hallucinations (CVH) due to visual loss. The underlying mechanism of CBS is not clear and the underlying pathophysiology of the visual hallucinations in CBS patients and pure visually impaired patients is still not clear. </P><P> Methods: In our study, we have scanned three patients with eye disease and CBS (VH+) and three patients with eye disease without CBS (VH-) using FDG-PET. Results: Our results showed underactivity in the pons and overactivity in primary right left visual cortex and inferior parietal cortex in VH- patients and underactivity in left Broca, left inf frontal primary visual cortex and anterior and posterior cingulate cortex in VH+ patients relative to the normative 18FFDG PET data that was taken from the database consisting of 50 age-matched healthy adults without neuropsychiatric disorders. Conclusion: From this distributed pattern of activity changes, we conclude that the generation of visual hallucination in CBS is associated with bottom-up and top-down mechanism rather than the generally accepted visual deafferentation-related hyperexcitability theory.

Corrigendum to “l-Dopa methyl ester attenuates amblyopia-induced neuronal injury in visual cortex of amblyopic cat” [Gene 527 (2013) 115–122]

Gene ◽  
2021 ◽  
Vol 777 ◽  
pp. 145477
Author(s):  
Rong Li ◽  
Tao Liang ◽  
Zhaoni Chen ◽  
Shijun Zhang ◽  
Xing Lin ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Methyl Ester ◽  
Neuronal Injury ◽  
Cat Gene

l-Dopa methyl ester attenuates amblyopia-induced neuronal injury in visual cortex of amblyopic cat

Gene ◽  
2013 ◽  
Vol 527 (1) ◽  
pp. 115-122
Author(s):  
Rong Li ◽  
Tao Liang ◽  
Zhaoni Chen ◽  
Shijun Zhang ◽  
Xing Lin ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Methyl Ester ◽  
Neuronal Injury

scholarly journals Topical Antinociceptive Effect ofVanillosmopsis arboreaBaker on Acute Corneal Pain in Mice

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Laura Hévila Inocêncio Leite ◽  
Gerlânia de Oliveira Leite ◽  
Thales Silva Coutinho ◽  
Severino Denício Gonçalves de Sousa ◽  
Renata Souza Sampaio ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Essential Oil ◽  
Antinociceptive Effect ◽  
Underlying Mechanism ◽  
Ruthenium Red ◽  
Test Model ◽  
Nacl Solution ◽  
Nociceptive Behavior ◽  
Corneal Surface ◽  
Central Muscarinic Receptors

This study aimed to assess the possible topical antinociceptive activity ofVanillosmopsis arboreaBaker essential oil (EOVA) and to clarify the underlying mechanism, using the acute model of chemical (eye wiping) nociception in mice. EOVA (25 to 200 mg/kg; p.o. and topical) evidenced significant antinociception against chemogenic pain in the test model of formalin-induced neuroinflammatory pain. Local application of 5 M NaCl solution on the corneal surface of the eye produced a significant nociceptive behavior, characterized by eye wiping. The number of eye wipes was counted during the first 30 s. EOVA (25, 50, 100, and 200 mg/kg; p.o. and topical) significantly decreased the number of eye wipes. Naloxone, yohimbine, L-NAME, theophylline, glibenclamide, and ruthenium red had no effect on the antinociceptive effect of EOVA. However, ondansetron, p-chlorophenylalanine methyl ester (PCPA), capsazepine, prazosin, and atropine prevented the antinociception induced by EOVA. These results indicate the topical antinociceptive effect of EOVA and showed that 5-HT,α1, TRPV1, and central muscarinic receptors might be involved in the antinociceptive effect of EOVA in the acute corneal model of pain in mice.

scholarly journals V1 receptive field structure contributes to neuronal response latency

2022 ◽  
Author(s):  
Amin Vafaei ◽  
Milad Mohammadi ◽  
Alireza Khadir ◽  
Erfan Zabeh ◽  
Faraz YazdaniBanafsheDaragh ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Response Latency ◽  
Neuronal Response ◽  
Underlying Mechanism ◽  
Geometrical Model ◽  
Fine Tuning ◽  
Neuronal Responses ◽  
Periodic Patterns ◽  
Response Latencies

The timing of neuronal responses is considered to be important for information transferring and communication across individual neurons. However, the sources of variabilities in the timing of neuronal responses are not well understood and sometimes over-interpreted. A systematic variability in the response latencies of the primary visual cortex has been reported in presence of drifting grating stimulus. Whereas the response latencies are systematically dependent on stimulus orientation. To understand the underlying mechanism of these systematic latencies, we recorded the neuronal response of the cat visual cortex, area 17, and simulated the response latency of V1 neurons, with two geometric models. We showed that outputs of these two models significantly predict the response latencies of the electrophysiology recording during orientation tasks. The periodic patterns created in the raster plots were dependent on the relative position of the stimulus rotation center and the receptive-field sub-regions. We argue the position of stimulus is contributing to systematic response latencies, dependent on drifting orientation. Therefore, we provide a toolbox based on our geometrical model for determining the exact location of RF sub-regions. Our result indicates that a major source of neuronal variability is the lack of fine-tuning in the task parameters. Considering the simplicity of the orientation selectivity task, we argue fine-tuning of stimulus properties is crucial for deduction of neural variability in higher-order cortical areas and understanding their neural dynamics.

scholarly journals Joint Encoding of Auditory Timing and Location in Visual Cortex

2019 ◽  
Vol 31 (7) ◽  
pp. 1002-1017 ◽  
Author(s):  
John Plass ◽  
EunSeon Ahn ◽  
Vernon L. Towle ◽  
William C. Stacey ◽  
Vibhangini S. Wasade ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Posterior Parietal Cortex ◽  
Maximal Activity ◽  
Underlying Mechanism ◽  
Significant Activity ◽  
Phase Reset ◽  
Phase Resetting ◽  
Posterior Parietal ◽  
Joint Encoding ◽  
The Relationship

Co-occurring sounds can facilitate perception of spatially and temporally correspondent visual events. Separate lines of research have identified two putatively distinct neural mechanisms underlying two types of crossmodal facilitations: Whereas crossmodal phase resetting is thought to underlie enhancements based on temporal correspondences, lateralized occipital evoked potentials (ERPs) are thought to reflect enhancements based on spatial correspondences. Here, we sought to clarify the relationship between these two effects to assess whether they reflect two distinct mechanisms or, rather, two facets of the same underlying process. To identify the neural generators of each effect, we examined crossmodal responses to lateralized sounds in visually responsive cortex of 22 patients using electrocorticographic recordings. Auditory-driven phase reset and ERP responses in visual cortex displayed similar topography, revealing significant activity in pericalcarine, inferior occipital–temporal, and posterior parietal cortex, with maximal activity in lateral occipitotemporal cortex (potentially V5/hMT+). Laterality effects showed similar but less widespread topography. To test whether lateralized and nonlateralized components of crossmodal ERPs emerged from common or distinct neural generators, we compared responses throughout visual cortex. Visual electrodes responded to both contralateral and ipsilateral sounds with a contralateral bias, suggesting that previously observed laterality effects do not emerge from a distinct neural generator but rather reflect laterality-biased responses in the same neural populations that produce phase-resetting responses. These results suggest that crossmodal phase reset and ERP responses previously found to reflect spatial and temporal facilitation in visual cortex may reflect the same underlying mechanism. We propose a new unified model to account for these and previous results.

scholarly journals Critical Interaction Between Telomerase and Autophagy in Mediating Flow-Induced Human Arteriolar Vasodilation

2020 ◽  
Author(s):  
William E. Hughes ◽  
Dawid S. Chabowski ◽  
Karima Ait-Aissa ◽  
Jessica L. Fetterman ◽  
Joseph Hockenberry ◽  
...  
Keyword(s):  
Shear Stress ◽  
Polyethylene Glycol ◽  
Methyl Ester ◽  
Underlying Mechanism ◽  
Telomerase Activity ◽  
Left Ventricular ◽  
Autophagic Flux ◽  
Common Denominator ◽  
Telomerase Inhibitor ◽  
Artery Disease

Objective: Coronary artery disease (CAD) is associated with a compensatory switch in mechanism of flow-mediated dilation (FMD) from nitric oxide (NO) to H 2 O 2 . The underlying mechanism responsible for the pathological shift is not well understood, and recent reports directly implicate telomerase and indirectly support a role for autophagy. We hypothesize that autophagy is critical for shear stress–induced release of NO and is a crucial component of for the pathway by which telomerase regulates FMD. Approach and Results: Human left ventricular, atrial, and adipose resistance arterioles were collected for videomicroscopy and immunoblotting. FMD and autophagic flux were measured in arterioles treated with autophagy modulators alone, and in tandem with telomerase-activity modulators. LC3B II/I was higher in left ventricular tissue from patients with CAD compared with non-CAD (2.8±0.2 versus 1.0±0.2-fold change; P <0.05), although p62 was similar between groups. Shear stress increased Lysotracker fluorescence in non-CAD arterioles, with no effect in CAD arterioles. Inhibition of autophagy in non-CAD arterioles induced a switch from NO to H 2 O 2 , while activation of autophagy restored NO-mediated vasodilation in CAD arterioles. In the presence of an autophagy activator, telomerase inhibitor prevented the expected switch (Control: 82±4%; NG-Nitro-l-arginine methyl ester: 36±5%; polyethylene glycol catalase: 80±3). Telomerase activation was unable to restore NO-mediated FMD in the presence of autophagy inhibition in CAD arterioles (control: 72±7%; NG-Nitro-l-arginine methyl ester: 79±7%; polyethylene glycol catalase: 38±9%). Conclusions: We provide novel evidence that autophagy is responsible for the pathological switch in dilator mechanism in CAD arterioles, demonstrating that autophagy acts downstream of telomerase as a common denominator in determining the mechanism of FMD.

scholarly journals Transplanted cells are essential for the induction but not the expression of cortical plasticity

2019 ◽  
Author(s):  
Mahmood S. Hoseini ◽  
Benjamin Rakela ◽  
Quetzal Flores-Ramirez ◽  
Andrea R. Hasenstaub ◽  
Arturo Alvarez-Buylla ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Critical Period ◽  
Cortical Plasticity ◽  
Ocular Dominance ◽  
Underlying Mechanism ◽  
Adult Brain ◽  
Inhibitory Neurons ◽  
Cortical Responses ◽  
Parallel Circuit ◽  
Activity Dependent

AbstractTransplantation of even a small number of embryonic inhibitory neurons from the medial ganglionic eminence (MGE) into postnatal visual cortex makes it lose responsiveness to an eye deprived of vision when the transplanted neurons reach the age of the normal critical period of activity-dependent ocular dominance (OD) plasticity. The transplant might induce OD plasticity in the host circuitry or might instead construct a parallel circuit of its own to suppress cortical responses to the deprived-eye. We transplanted MGE neurons expressing archaerhodopsin, closed one eyelid for 4-5 days, and, as expected, observed transplant-induced OD plasticity. This plasticity was evident even when the activity of the transplanted cells was suppressed optogenetically, demonstrating that the plasticity was produced by changes in the host visual cortex.Significance StatementInterneuron transplantation into mouse V1 creates a window of heightened plasticity which is quantitatively and qualitatively similar to the normal critical period, i.e. short-term occlusion of either eye markedly changes ocular dominance. The underlying mechanism of this process is not known. Transplanted interneurons might either form a separate circuit to maintain the ocular dominance shift or might instead trigger changes in the host circuity. We designed experiments to distinguish the two hypotheses. Our findings suggest that while inhibition produced by the transplanted cells triggers this form of plasticity, the host circuity is entirely responsible for maintaining the ocular dominance shift.One Sentence SummaryNeuronal transplants do not just grow and connect—they induce plasticity in the adult brain.

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