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Cortical visual impairment

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https://www.readbyqxmd.com/read/29031830/action-observation-facilitates-motor-cortical-activity-in-patients-with-stroke-and-hemiplegia
#1
Marina Tani, Yumie Ono, Miku Matsubara, Satoko Ohmatsu, Yoshihiro Yukawa, Masashi Kohno, Takanori Tominaga
Motor imagery (MI) is a mental practice that reproduces the visual- and/or kinesthetic-modality brain activations accompanying movement. It is a useful rehabilitation technique as the affected motor cortex can be stimulated in patients with stroke and hemiplegia. However, most patients with stroke have difficulty with MI owing to advanced age and/or higher-cognitive dysfunction, thus impairing their ability to internally simulate the action. We therefore investigated whether action observation (AO), an alternative form of motor stimulation that works via the mirror-neuron system, could facilitate motor cortical activity in such patients...
October 12, 2017: Neuroscience Research
https://www.readbyqxmd.com/read/29027577/assessment-of-renal-perfusion-impairment-in-a-rat-model-of-acute-renal-congestion-using-contrast-enhanced-ultrasonography
#2
Kaoru Komuro, Yoshihiro Seo, Masayoshi Yamamoto, Seika Sai, Tomoko Ishizu, Kyo Shimazu, Yumi Takahashi, Shogo Imagawa, Teisuke Anzai, Kazuya Yonezawa, Kazutaka Aonuma
Renal congestion is caused by elevated central venous pressure (CVP), and decreases glomerular filtration in patients with congestive heart failure. Since real-time contrast-enhanced ultrasonography (CEUS) using microbubble-based contrast agents can visualize the perfused microvascular bed, we sought to evaluate the impairment of renal perfusion during acute renal congestion with CEUS. In Wister rats, CEUS of kidney was performed with the direct monitoring of CVP and intra-renal pressure (IRP). When CVP was elevated to 10 and 15 mmHg after the bolus injection of normal saline via the femoral vein, peak intensity (PI, dB) and time to PI (TTP) in the renal cortex and medulla were compared with control rats...
October 13, 2017: Heart and Vessels
https://www.readbyqxmd.com/read/29026095/alterations-of-regional-homogeneity-and-functional-connectivity-in-pituitary-adenoma-patients-with-visual-impairment
#3
Guidong Song, Jicheng Qiu, Chuzhong Li, Jiye Li, Songbai Gui, Haibo Zhu, Yazhuo Zhang
Evidences have showed that the deprivation of vision can considerably alter the resting-state activity both within and beyond the visual cortices. However, the functional changes of the brain cortices related to partially vision-deprivation are still largely unknown. Using resting-state functional MR imaging, we quantitatively evaluated the regional homogeneity(ReHo) and functional connectivity(FC) changes between 25 pituitary adenoma patients with visual impairment and 25 healthy controls(HCs). Compared with HCs, PAs exhibited significant increased ReHo in the left superior occipital gyrus, bilateral middle occipital gyrus and reduced ReHo in the left inferior frontal gyrus and right middle temporal gyrus...
October 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29023523/the-role-of-glutamate-in-neuronal-ion-homeostasis-a-case-study-of-spreading-depolarization
#4
Niklas Hübel, Mahshid S Hosseini-Zare, Jokūbas Žiburkus, Ghanim Ullah
Simultaneous changes in ion concentrations, glutamate, and cell volume together with exchange of matter between cell network and vasculature are ubiquitous in numerous brain pathologies. A complete understanding of pathological conditions as well as normal brain function, therefore, hinges on elucidating the molecular and cellular pathways involved in these mostly interdependent variations. In this paper, we develop the first computational framework that combines the Hodgkin-Huxley type spiking dynamics, dynamic ion concentrations and glutamate homeostasis, neuronal and astroglial volume changes, and ion exchange with vasculature into a comprehensive model to elucidate the role of glutamate uptake in the dynamics of spreading depolarization (SD)-the electrophysiological event underlying numerous pathologies including migraine, ischemic stroke, aneurysmal subarachnoid hemorrhage, intracerebral hematoma, and trauma...
October 12, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28989044/preoperative-navigated-transcranial-magnetic-stimulation-and-tractography-to-guide-endoscopic-cystoventriculostomy-a-technical-note-and-case-report
#5
Philipp Hendrix, Sebastian Senger, Christoph J Griessenauer, Andreas Simgen, Stefan Linsler, Joachim Oertel
OBJECTIVE: To report a technique for endoscopic cystoventriculostomy guided by preoperative navigated transcranial magnetic stimulation (nTMS) and tractography in a patient suffering from a large speech eloquent arachnoid cyst. METHODS: A 74-year old woman presented with a seizure and subsequent persistent anomic aphasia from a progressive left-sided parietal arachnoid cyst. An endoscopic cystoventriculostomy and endoscope-assisted ventricle catheter placement were performed...
October 5, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28974380/neural-evidence-for-defective-top-down-control-of-visual-processing-in-parkinson-s-and-alzheimer-s-disease
#6
Nela Nemcova Elfmarkova, Martin Gajdos, Irena Rektorova, Radek Marecek, Steven Z Rapcsak
INTRODUCTION: We used a functional MRI paradigm involving conventional vs. unconventional views of objects to assess bottom-up vs. top-down visual processing in Parkinson's disease (PD) with normal cognition, PD with mild cognitive impairment (MCI), and MCI due to Alzheimer's disease (AD) as compared to healthy controls. We particularly aimed at determining whether the task discriminated between PD with and without MCI and between two MCI groups due to distinct pathologies (AD and PD)...
September 30, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/28971005/auditory-cross-modal-reorganization-in-cochlear-implant-users-indicates-audio-visual-integration
#7
Maren Stropahl, Stefan Debener
There is clear evidence for cross-modal cortical reorganization in the auditory system of post-lingually deafened cochlear implant (CI) users. A recent report suggests that moderate sensori-neural hearing loss is already sufficient to initiate corresponding cortical changes. To what extend these changes are deprivation-induced or related to sensory recovery is still debated. Moreover, the influence of cross-modal reorganization on CI benefit is also still unclear. While reorganization during deafness may impede speech recovery, reorganization also has beneficial influences on face recognition and lip-reading...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28964930/grasping-with-a-new-hand-improved-performance-and-normalized-grasp-selective-brain-responses-despite-persistent-functional-changes-in-primary-motor-cortex-and-low-level-sensory-and-motor-impairments
#8
Kenneth F Valyear, Daniela Mattos, Benjamin A Philip, Christina Kaufman, Scott H Frey
Hand loss can now be reversed through surgical transplantation years or decades after amputation. Remarkably, these patients come to use their new hand to skilfully grasp and manipulate objects. The brain mechanisms that make this possible are unknown. Here we test the hypothesis that the anterior intraparietal cortex (aIPC) - a multimodal region implicated in hand preshaping and error correction during grasping - plays a key role in this compensatory grasp control. Motion capture and fMRI are used to characterize hand kinematics and brain responses during visually guided grasping with a transplanted hand at 26 and 41 months post-transplant in patient DR, a former hand amputee of 13 years...
September 28, 2017: NeuroImage
https://www.readbyqxmd.com/read/28951164/the-orbitofrontal-cortex-and-emotion-in-health-and-disease-including-depression
#9
Edmund T Rolls
The orbitofrontal cortex represents the reward or affective value of primary reinforcers including taste, touch, texture, and face expression. It learns to associate other stimuli with these to produce representations of the expected reward value for visual, auditory, and abstract stimuli including monetary reward value. The orbitofrontal cortex thus plays a key role in emotion, by representing the reward value of the goals for action. The learning process is stimulus-reinforcer association learning. Negative reward prediction error neurons are related to this affective learning...
September 24, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/28941531/disentangling-how-the-brain-is-wired-in-cortical-cerebral-visual-impairment
#10
Lotfi B Merabet, D Luisa Mayer, Corinna M Bauer, Darick Wright, Barry S Kran
Cortical (cerebral) visual impairment (CVI) results from perinatal injury to visual processing structures and pathways of the brain and is the most common cause of severe visual impairment or blindness in children in developed countries. Children with CVI display a wide range of visual deficits including decreased visual acuity, impaired visual field function, as well as impairments in higher-order visual processing and attention. Together, these visual impairments can dramatically influence a child's development and well-being...
May 2017: Seminars in Pediatric Neurology
https://www.readbyqxmd.com/read/28940697/altered-white-matter-integrity-in-unaffected-siblings-of-probands-with-autism-spectrum-disorders
#11
Yi-Ling Chien, Yu-Jen Chen, Yung-Chin Hsu, Wen-Yih Isaac Tseng, Susan Shur-Fen Gau
Despite the evidence of altered white-matter tract property in individuals with autism spectrum disorder (ASD), little is known about their unaffected siblings. This study aimed to investigate white-matter integrity in unaffected siblings of ASD probands. Thirty-nine unaffected siblings (mean age 15.6 ± 6.0 years; 27 males, 69.2%) and 39 typically developing controls (TDC) (14.2 ± 5.6 years; 26 males, 66.7%) were assessed with diffusion spectrum images and neuropsychological tests. Using the tract-based automatic analysis and the threshold-free cluster weighted (TFCW) scores, we searched for the segments among 76 tracts with the largest difference over the entire brain compared to TDC...
September 20, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28936822/-posterior-reversible-encephalopathy-syndrome-triggerred-by-alcohol-withdrawal
#12
Tuğçe Mengi, Yaprak Seçil, Aysel Çoban, Yeşim Beckmann
INTRODUCTION: Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological entity characterized by headache, altered mental status, epileptic seizures, visual disturbances and typically transient changes in posterior cerebral circulation areas. In this article, we present a case of alcohol withdrawal accompanied by PRES. CASE PRESENTATION: A 53-year-old male patient presented to the emergency department with visual hallucinations and meaningless speech...
2017: Türk Psikiyatri Dergisi, Turkish Journal of Psychiatry
https://www.readbyqxmd.com/read/28929921/clinical-implications-of-interictal-epileptiform-discharges-in-cognitive-functioning-in-cec-syndrome-with-evolution-into-epileptic-encephalopathy
#13
Paolo Bonanni, Susanna Negrin, Lisa Antoniazzi, Martina Da Rold, Franco Fabbro, Anna Serafini
In epileptic encephalopathies (EE), interictal epileptiform discharges (IEDs) contribute to cognitive impairment. The EE process has been studied in a patient affected by epilepsy with occipital calcification and celiac disease (CEC syndrome) by combining the administration of brain area stimulus specific (visual and auditory) reaction times (RT) during continuous EEG monitoring with the off-line reconstruction of auditory and visual evoked potentials (EP). Visual RT and VEP were abnormal only if recorded concomitantly to the IEDs...
September 20, 2017: Neurocase
https://www.readbyqxmd.com/read/28928986/cholinergic-potentiation-of-restoration-of-visual-function-after-optic-nerve-damage-in-rats
#14
Mira Chamoun, Elena G Sergeeva, Petra Henrich-Noack, Shaobo Jia, Lisa Grigartzik, Jing Ma, Qing You, Frédéric Huppé-Gourgues, Bernhard A Sabel, Elvire Vaucher
Enhancing cortical plasticity and brain connectivity may improve residual vision following a visual impairment. Since acetylcholine plays an important role in attention and neuronal plasticity, we explored whether potentiation of the cholinergic transmission has an effect on the visual function restoration. To this end, we evaluated for 4 weeks the effect of the acetylcholinesterase inhibitor donepezil on brightness discrimination, visually evoked potentials, and visual cortex reactivity after a bilateral and partial optic nerve crush in adult rats...
2017: Neural Plasticity
https://www.readbyqxmd.com/read/28918222/vision-assessments-and-interventions-for-infants-0-2-years-at-high-risk-for-cerebral-palsy-a-systematic-review
#15
REVIEW
Olena D Chorna, Andrea Guzzetta, Nathalie L Maitre
We performed a systematic review and evaluated the level of evidence of vision interventions and assessments for infants at high risk for or with a diagnosis of cerebral palsy from 0 to 2 years of age. Articles were evaluated based on the level of methodologic quality, evidence, and clinical utilization. Thirty publications of vision assessments and five of vision interventions met criteria for inclusion. Assessments included standard care neuroimaging, electrophysiology, and neuro-ophthalmologic examination techniques that are utilized clinically with any preverbal or nonverbal pediatric patient...
July 20, 2017: Pediatric Neurology
https://www.readbyqxmd.com/read/28915853/low-threshold-unmyelinated-mechanoafferents-can-modulate-pain
#16
Kathrin Habig, Anne Schänzer, Wolfgang Schirner, Gothje Lautenschläger, Benjamin Dassinger, Håkan Olausson, Frank Birklein, Elke R Gizewski, Heidrun H Krämer
BACKGROUND: Human, hairy skin contains a subgroup of C-fibers, the C-low threshold mechanoreceptive afferents ((C-LTMR) C-tactile or C-touch (CT) fibers) that are linked with the signaling of affective aspects of human touch. Recent studies suggest an involvement of these afferents in the modulation of pain in healthy volunteers. Small fiber neuropathy (SFN) is associated with a damage of C-fibers. Therefore, an impairment of C-LTMRs can be assumed. We aimed to elaborate a possible role of CT-afferents in pain modulation by investigating healthy volunteers and SFN-patients...
September 15, 2017: BMC Neurology
https://www.readbyqxmd.com/read/28912694/from-cortical-blindness-to-conscious-visual-perception-theories-on-neuronal-networks-and-visual-training-strategies
#17
REVIEW
Vanessa Hadid, Franco Lepore
Homonymous hemianopia (HH) is the most common cortical visual impairment leading to blindness in the contralateral hemifield. It is associated with many inconveniences and daily restrictions such as exploration and visual orientation difficulties. However, patients with HH can preserve the remarkable ability to unconsciously perceive visual stimuli presented in their blindfield, a phenomenon known as blindsight. Unfortunately, the nature of this captivating residual ability is still misunderstood and the rehabilitation strategies in terms of visual training have been insufficiently exploited...
2017: Frontiers in Systems Neuroscience
https://www.readbyqxmd.com/read/28912150/-18-f-fdg-pet-in-parkinsonism-differential-diagnosis-and-cognitive-impairment-in-parkinson-s-disease
#18
Philipp T Meyer, Lars Frings, Gerta Rücker, Sabine Hellwig
Accurate differential diagnosis of parkinsonism is of a paramount therapeutic and prognostic importance. In addition, with the development of invasive therapies and novel disease-specific therapies, strategies for patient enrichment in trial populations are of growing importance. Imaging disease-specific patterns of regional glucose metabolism with positron emission tomography and [(18)F]fluoro-2-deoxy-2-D-glucose ((18)F-FDG) allows for a highly accurate distinction between Parkinson's disease (PD) and atypical parkinsonian syndromes (APS) including multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD)...
September 14, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28899917/activity-dependent-dysfunction-in-visual-and-olfactory-sensory-systems-in-mouse-models-of-down-syndrome
#19
Christopher M William, Lubna Saqran, Matthew A Stern, Charles L Chiang, Scott Herrick, Aziz Rangwala, Mark W Albers, Matthew P Frosch, Bradley T Hyman
Activity-dependent synaptic plasticity plays a critical role in the refinement of circuitry during postnatal development and may be disrupted in conditions that cause intellectual disability such as Down syndrome (DS). To test this hypothesis, visual cortical plasticity was assessed in Ts65Dn mice that harbor a chromosomal duplication syntenic to human chromosome 21q. We find that Ts65Dn mice demonstrate a defect in ocular dominance plasticity (ODP) following monocular deprivation. This phenotype is similar to that of transgenic mice that express amyloid precursor protein (APP), which is duplicated in DS and in Ts65DN mice; however, normalizing APP gene copy number in Ts65Dn mice fails to rescue plasticity...
September 12, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28875311/bisphenol-a-exposure-perturbs-visual-function-of-adult-cats-by-remodeling-the-neuronal-activity-in-the-primary-visual-pathway
#20
Guangwei Xu, Fan Hu, Xuan Wang, Bing Zhang, Yifeng Zhou
Bisphenol A (BPA), a common environmental xenoestrogen, has been implicated in physiological and behavioral impairment, but the neuronal basis remains elusive. Although various synaptic mechanisms have been shown to mediate BPA-induced brain deficits, there are almost no reports addressing its underlying physiological mechanisms at the individual neuron level, particularly in the primary visual system. In the present study, using multiple-channel recording technique, we recorded the responses of single neurons in the primary visual system of cats to various direction stimuli both before and after BPA exposure...
September 5, 2017: Archives of Toxicology
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