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Lateral geniculate nucleus

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https://www.readbyqxmd.com/read/28714121/acetylcholine-dependent-upregulation-of-task-1-channels-in-thalamic-interneurons-by-a-smooth-muscle-like-signalling-pathway
#1
Michael Leist, Susanne Rinné, Maia Datunashvili, Ania Aissaoui, Hans-Christian Pape, Niels Decher, Sven G Meuth, Thomas Budde
The dorsal part of the lateral geniculate nucleus (dLGN) is the main thalamic site for state-dependent transmission of visual information. Non-retinal inputs from the ascending arousal system and inhibition provided by γ-aminobutyric acid (GABA)ergic local circuit interneurons (INs) control neuronal activity within the dLGN. In particular, acetylcholine (ACh) depolarizes thalamocortical relay (TC) neurons by inhibiting two-pore domain potassium (K2P ) channels. Conversely, ACh also hyperpolarizes INs via an as-yet-unknown mechanism...
July 17, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28711710/comparison-of-the-role-of-metabotropic-glutamate-receptor-subtype-1-in-developmental-refinement-of-neuronal-connectivity-between-the-cerebellum-and-the-sensory-thalamus
#2
REVIEW
Madoka Narushima
Developmental refinement of neuronal connectivity is crucial for proper brain function. In the early phase of development, input fibers arrive at their target areas guided by specific molecular cues and form abundant immature synapses. Then, functionally important synapses are preserved and strengthened by neural activity while unnecessary synapses are eliminated. Afferent synapses in the sensory thalamus, such as from retina to lateral geniculate nucleus, and climbing fiber (CF)-Purkinje cell (PC) synapses in the cerebellum are valuable models for studying this developmental refinement of synaptic connectivity because only a limited number of input fibers innervate a given postsynaptic thalamocortical (TC) neuron or PC...
July 12, 2017: Neuroscience Research
https://www.readbyqxmd.com/read/28696183/visual-system-involvement-in-patients-with-newly-diagnosed-parkinson-disease
#3
Alessandro Arrigo, Alessandro Calamuneri, Demetrio Milardi, Enricomaria Mormina, Laura Rania, Elisa Postorino, Silvia Marino, Giuseppe Di Lorenzo, Giuseppe Pio Anastasi, Maria Felice Ghilardi, Pasquale Aragona, Angelo Quartarone, Michele Gaeta
Purpose To assess intracranial visual system changes of newly diagnosed Parkinson disease in drug-naïve patients. Materials and Methods Twenty patients with newly diagnosed Parkinson disease and 20 age-matched control subjects were recruited. Magnetic resonance (MR) imaging (T1-weighted and diffusion-weighted imaging) was performed with a 3-T MR imager. White matter changes were assessed by exploring a white matter diffusion profile by means of diffusion-tensor imaging-based parameters and constrained spherical deconvolution-based connectivity analysis and by means of white matter voxel-based morphometry (VBM)...
July 11, 2017: Radiology
https://www.readbyqxmd.com/read/28639357/cerebellar-projections-to-the-ventral-lateral-geniculate-nucleus-and-the-thalamic-reticular-nucleus-in-the-cat
#4
Hiroyuki Nakamura
The ventral lateral geniculate nucleus (LGNv) is a retinorecipient part of the ventral thalamus and in cats, it consists of medial (M), medial intermediate (IM), lateral intermediate (IL), lateral (L), and dorsal (D) subdivisions. These subdivisions can be differentiated not only by their cytoarchitecture, but also by their connectivity and putative functions. The LGNv may play a role in visuomotor gating, in that there is evidence of cerebellar afferent projections to the intermediate subdivisions. The cerebellar posterior interpositus (IP) and lateral (LC) nuclei are known to project to IM and IL, but the specifics of these projections are unclear...
June 22, 2017: Journal of Neuroscience Research
https://www.readbyqxmd.com/read/28634086/towards-building-a-more-complex-view-of-the-lateral-geniculate-nucleus-recent-advances-in-understanding-its-role
#5
REVIEW
Masoud Ghodrati, Seyed-Mahdi Khaligh-Razavi, Sidney R Lehky
The lateral geniculate nucleus (LGN) has often been treated in the past as a linear filter that adds little to retinal processing of visual inputs. Here we review anatomical, neurophysiological, brain imaging, and modeling studies that have in recent years built up a much more complex view of LGN. These include effects related to nonlinear dendritic processing, cortical feedback, synchrony and oscillations across LGN populations, as well as involvement of LGN in higher level cognitive processing Although recent studies have provided valuable insights into early visual processing including the role of LGN, a unified model of LGN responses to real-world objects has not yet been developed...
June 17, 2017: Progress in Neurobiology
https://www.readbyqxmd.com/read/28632031/mr-imaging-of-the-anterior-visual-pathway-in-primary-open-angle-glaucoma-correlation-with-octopus-101-perimetry-and-spectralis-optical-coherence-tomography-findings
#6
Mehmet Giray Ersoz, Yeliz Pekcevik, Emre Ayintap, İrfan Botan Gunes, Duygu Kunak Mart, Ersin Yucel, Gamze Türe
PURPOSE: To investigate structural changes in the visual pathway measured by magnetic resonance imaging (MRI) and its relationship with the clinical severity of glaucoma in primary open-angle glaucoma (POAG) patients. MATERIALS AND METHODS: The study included 28 patients with POAG and 26 age- and sex-matched healthy volunteers. All the subjects underwent spectral domain optical coherence tomography (OCT) of the peripapillary retina nerve fiber layer (RNFL). The optic nerve diameter (OND), chiasma height (Ch), and lateral geniculate nucleus height (LGNh) were measured bilaterally using a 1...
February 28, 2017: Current Eye Research
https://www.readbyqxmd.com/read/28622391/neuronal-substrates-underlying-stress-resilience-and-susceptibility-in-rats
#7
Fabia Febbraro, Katrine Svenningsen, Thao Phuong Tran, Ove Wiborg
BACKGROUND: Stress and stressful life events have repeatedly been shown as causally related to depression. The Chronic Mild Stress rat model is a valid model of stress-induced depression. Like humans, rats display great heterogeneity in their response to stress and adversity. Hence some individuals are stress-sensitive and prone to develop depression-like behaviour in response to modest stressors, while others are stress-resilient and remain essentially symptom free. OBJECTIVES: Compared to the large body of research, which describes stress-induced maladaptive neurobiological changes, relatively little attention has been devoted to understand resiliency to stress...
2017: PloS One
https://www.readbyqxmd.com/read/28607399/rim1-2-in-retinal-ganglion-cells-are-required-for-the-refinement-of-ipsilateral-axons-and-eye-specific-segregation
#8
Ahlem Assali, Corentin Le Magueresse, Mohamed Bennis, Xavier Nicol, Patricia Gaspar, Alexandra Rebsam
Neural activity is crucial for the refinement of neuronal connections during development, but the contribution of synaptic release mechanisms is not known. In the mammalian retina, spontaneous neural activity controls the refinement of retinal projections to the dorsal lateral geniculate nucleus (dLGN) and the superior colliculus (SC) to form appropriate topographic and eye-specific maps. To evaluate the role of synaptic release, the rab-interacting molecules (RIMs), a family of active zone proteins that play a central role in calcium-triggered release, were conditionally ablated in a subset of retinal ganglion cells (RGCs)...
June 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28587872/validation-of-an-automated-tractography-method-for-the-optic-radiations-as-a-biomarker-of-visual-acuity-in-neurofibromatosis-associated-optic-pathway-glioma
#9
REVIEW
Peter de Blank, Michael J Fisher, Haley Gittleman, Jill S Barnholtz-Sloan, Chaitra Badve, Jeffrey I Berman
INTRODUCTION: Fractional anisotropy (FA) of the optic radiations has been associated with vision deficit in multiple intrinsic brain pathologies including NF1 associated optic pathway glioma, but hand-drawn regions of interest used in previous tractography methods limit consistency of this potential biomarker. We created an automated method to identify white matter tracts in the optic radiations and compared this method to previously reported hand-drawn tractography. METHOD: Automated tractography of the optic radiation using probabilistic streamline fiber tracking between the lateral geniculate nucleus of the thalamus and the occipital cortex was compared to the hand-drawn method between regions of interest posterior to Meyer's loop and anterior to tract branching near the calcarine cortex...
June 3, 2017: Experimental Neurology
https://www.readbyqxmd.com/read/28577432/psychophysical-assessment-of-koniocellular-pathway-in-patients-with-schizophrenia-versus-healthy-controls
#10
Ozgur Bulent Timucin, Elif Aktan Mutlu, Damla Timucin, Mehmet Emin Aslanci, Isil Isikligil, Mehmet Fatih Karadag, Esra Kizildag Ozbay
This study was designed to perform psychophysical assessment of koniocellular pathway in patients with schizophrenia versus healthy controls. A total of 26 patients diagnosed with schizophrenia and 15 healthy controls were included. Snellen Visual Acuity Chart scores and Short Wavelength Automated Perimetry (SWAP) visual field testing including global visual field indices [mean deviation (MD), pattern standard deviation (PSD), test time (min)], reliability parameters [false negative responses (%), false positive responses (%) and fixed losses (%)] and average threshold sensitivity [central (parafovea), peripheral area, and four quadrants] were recorded in both groups...
May 26, 2017: Psychiatry Research
https://www.readbyqxmd.com/read/28539242/manganese-enhanced-mr-imaging-memri-combined-with-electrophysiology-in-the-study-of-cross-modal-plasticity-in-binocularly-blind-rats
#11
Zuohua Tang, Lingjie Wu, Zebin Xiao, Xinghuai Sun, Xiaoyuan Feng, Qian Chen, Jiawen Fan, Jie Wang, Wentao Wang, Jianfeng Luo, Lixin Jin
Our study aimed to determine and verify the establishment of visual to auditory cross-modal plasticity using manganese-enhanced MR imaging (MEMRI) combined with examinations of the visual evoked potential (VEP), auditory brainstem response (ABR) and bilateral visual cortex response to a bilateral auditory stimulus (AVR). Fourteen healthy male Sprague-Dawley newborn rats were randomly divided into 2 groups (n=7 per group). Optic nerve transection was performed in the 7 rats of Group A three weeks after birth to obtain binocularly blind models, and the 7 rats of Group B were maintained as the control group...
May 21, 2017: International Journal of Developmental Neuroscience
https://www.readbyqxmd.com/read/28528909/melanopsin-contributions-to-the-representation-of-images-in-the-early-visual-system
#12
Annette E Allen, Riccardo Storchi, Franck P Martial, Robert A Bedford, Robert J Lucas
Melanopsin photoreception enhances retinal responses to variations in ambient light (irradiance) and drives non-image-forming visual reflexes such as circadian entrainment [1-6]. Melanopsin signals also reach brain regions responsible for form vision [7-9], but melanopsin's contribution, if any, to encoding visual images remains unclear. We addressed this deficit using principles of receptor silent substitution to present images in which visibility for melanopsin versus rods+cones was independently modulated, and we recorded evoked responses in the mouse dorsal lateral geniculate nucleus (dLGN; thalamic relay for cortical vision)...
June 5, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28498493/involvement-of-microglia-in-early-axoglial-alterations-of-the-optic-nerve-induced-by-experimental-glaucoma
#13
Melina P Bordone, María F González Fleitas, Laura A Pasquini, Alejandra Bosco, Pablo H Sande, Ruth E Rosenstein, Damián Dorfman
Glaucoma is a leading cause of blindness, characterized by retinal ganglion cell (RGC) loss and optic nerve (ON) damage. Cumulative evidence suggests glial cell involvement in the degeneration of the ON and RGCs. We analyzed the contribution of microglial reactivity to early axoglial alterations of the ON in an induced model of ocular hypertension. For this purpose, vehicle or chondroitin sulfate (CS) were weekly injected into the eye anterior chamber from Wistar rats for different intervals. The amount of Brn3a(+) RGC significantly decreased in CS-injected eyes for 10 and 15 (but not 6) weeks...
May 12, 2017: Journal of Neurochemistry
https://www.readbyqxmd.com/read/28466070/a-cre-mouse-line-for-probing-irradiance-and-direction-encoding-retinal-networks
#14
Shai Sabbah, Daniel Berg, Carin Papendorp, Kevin L Briggman, David M Berson
Cell type-specific Cre driver lines have revolutionized the analysis of retinal cell types and circuits. We show that the transgenic mouse Rbp4-Cre selectively labels several retinal neuronal types relevant to the encoding of absolute light intensity (irradiance) and visual motion. In the ganglion cell layer (GCL), most marked cells are wide-field spiking polyaxonal amacrine cells (ACs) with sustained irradiance-encoding ON responses that persist during chemical synaptic blockade. Their arbors spread about 1 mm across the retina and are restricted to the inner half of the ON sublamina of the inner plexiform layer (IPL)...
March 2017: ENeuro
https://www.readbyqxmd.com/read/28461138/distribution-of-asic4-transcripts-in-the-adult-wild-type-mouse-brain
#15
M Hoshikawa, A Kato, H Hojo, Y Shibata, N Kumamoto, M Watanabe, S Ugawa
Acid-sensing ion channel 4 (ASIC4) belongs to the ASIC gene family of neuronal proton-gated cation channels, and is the least understood subtype among the members. Previous studies of ASIC4 expression in the mammalian central nervous system have shown that ASIC4 is abundantly expressed in the spinal cord and in various brain regions, such as the cerebral cortex, the hippocampus, and the cerebellum. However, the detailed distribution of ASIC4 transcripts in mammalian brains still remains to be elucidated. In the present study, radioactive in situ hybridization histochemistry with an ASIC4-specific cRNA probe was performed on wild-type mouse brains, followed by X-gal staining experiments with Asic4-lacZ reporter mice Asic4(tm1a(KOMP)Mbp)...
April 29, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28445782/the-immunohistochemical-distribution-of-the-gabaa-receptor-%C3%AE-1-%C3%AE-2-%C3%AE-3-%C3%AE-2-3-and-%C3%AE-2-subunits-in-the-human-thalamus
#16
H J Waldvogel, M Munkle, W van Roon-Mom, H Mohler, R L M Faull
The GABAA receptor is the most abundant inhibitory receptor in the human brain and is assembled from a variety of different subunit subtypes which determines their pharmacology and physiology. To determine which GABAA receptor subunit proteins are found in the human thalamus we investigated the distribution of five major GABAA receptor subunits α1, α2, α3, β2,3 and γ2 using immunohistochemical techniques. The α1-, β2,3- and γ2- subunits which combine to form a benzodiazepine sensitive GABAA receptor showed the most intense levels of staining and were the most common subunits found throughout the human thalamus especially in the ventral and posterior nuclear groups...
April 23, 2017: Journal of Chemical Neuroanatomy
https://www.readbyqxmd.com/read/28438969/intracellular-in-vivo-dynamics-of-thalamocortical-synapses-in-visual-cortex
#17
Madineh Sedigh-Sarvestani, Leif Vigeland, Ivan Fernandez-Lamo, M Morgan Taylor, Larry A Palmer, Diego Contreras
Seminal studies of the thalamocortical circuit in the visual system of the cat have been central to our understanding of sensory encoding. However, thalamocortical synaptic properties remain poorly understood. We used paired recordings, in the lateral geniculate nucleus (LGN) and primary visual cortex (V1), to provide the first in vivo characterization of sensory-driven thalamocortical potentials in V1. The amplitudes of EPSPs we characterized were smaller than those previously reported in vitro Consistent with prior findings, connected LGN-V1 pairs were only found when their receptive fields (RFs) overlapped, and the probability of connection increased steeply with degree of RF overlap and response similarity...
May 24, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28438183/semaphorin-plexin-signaling-influences-early-ventral-telencephalic-development-and-thalamocortical-axon-guidance
#18
Manuela D Mitsogiannis, Graham E Little, Kevin J Mitchell
BACKGROUND: Sensory processing relies on projections from the thalamus to the neocortex being established during development. Information from different sensory modalities reaching the thalamus is segregated into specialized nuclei, whose neurons then send inputs to cognate cortical areas through topographically defined axonal connections. Developing thalamocortical axons (TCAs) normally approach the cortex by extending through the subpallium; here, axonal navigation is aided by distributed guidance cues and discrete cell populations, such as the corridor neurons and the internal capsule (IC) guidepost cells...
April 24, 2017: Neural Development
https://www.readbyqxmd.com/read/28436881/modulating-lateral-geniculate-nucleus-neuronal-firing-for-visual-prostheses-a-kalman-filter-based-strategy
#19
Amr Jawwad, Hossam H Abolfotuh, Bassem Abdullah, Hani M K Mahdi, Seif Eldawlatly
Developing visual prostheses that target inner brain structures along the visual pathway represent a new hope for patients with completely damaged early visual pathway sites. One of the major challenges in the development of subcortical and cortical visual prostheses is tuning electrical stimulation that could optimally induce desired visual percepts. In this paper, we propose a Kalman filter-based strategy that could be used to identify electrical stimulation patterns that mimic a specific visual input for thalamic visual prostheses...
April 17, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28420966/fast-and-slow-inhibition-in-the-visual-thalamus-is-influenced-by-allocating-gabaa-receptors-with-different-%C3%AE-subunits
#20
Stephen G Brickley, Zhiwen Ye, Xiao Yu, Catriona M Houston, Zahra Aboukhalil, Nicholas P Franks, William Wisden
Cell-type specific differences in the kinetics of inhibitory postsynaptic conductance changes (IPSCs) are believed to impact upon network dynamics throughout the brain. Much attention has focused on how GABAA receptor (GABAAR) α and β subunit diversity will influence IPSC kinetics, but less is known about the influence of the γ subunit. We have examined whether GABAAR γ subunit heterogeneity influences IPSC properties in the thalamus. The γ2 subunit gene was deleted from GABAARs selectively in the dorsal lateral geniculate nucleus (dLGN)...
2017: Frontiers in Cellular Neuroscience
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