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physiology of vision

Shi-Jun Weng, Jordan M Renna, Wei-Yi Chen, Xiong-Li Yang
Intrinsically photosensitive retinal ganglion cells (ipRGCs) are a special subset of retinal output neurons capable of detecting and responding to light via a unique photopigment called melanopsin. Melanopsin activation is essential to a wide array of physiological functions, especially to those related to non-image-forming vision. Since ipRGCs only constitute a very small proportion of retinal ganglion cells, targeted recording of melanopsin-driven responses used to be a big challenge to vision researchers...
2018: Methods in Molecular Biology
Hsin-Hao Yu, Nafiseh Atapour, Tristan A Chaplin, Katrina H Worthy, Marcello G P Rosa
Lesions of striate cortex (V1) trigger massive retrograde degeneration of neurons in the lateral geniculate nucleus (LGN). In primates, these lesions also lead to scotomas within which conscious vision is abolished. Mediation of residual visual capacity within these regions (blindsight) has been traditionally attributed to an indirect visual pathway to the extrastriate cortex, which involves the superior colliculus and pulvinar complex. However, recent studies have suggested that preservation of the LGN is critical for behavioral evidence of blindsight, raising the question of what type of visual information is channeled by remaining neurons in this structure...
March 19, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Joshua N Webb, Caroline Dong, Andres Bernal, Giuliano Scarcelli
The goal of this protocol is to mimic the biomechanics of physiological accommodation in a cost-efficient, practical manner. Accommodation is achieved through the contraction of the ciliary body and relaxation of zonule fibers, which results in the thickening of the lens necessary for near vision. Here, we present a novel, simple method in which accommodation is replicated by tensing the zonules connected to the lens capsule via a manual lens stretcher (MLS). This method monitors the radial stretching achieved by a lens when subjected to a consistent force and allows for a comparison of accommodating lenses, which can be stretched, to non-accommodating lenses, which cannot be stretched...
February 23, 2018: Journal of Visualized Experiments: JoVE
Kurt F Heiss, Mehul V Raval
For over 20 years enhanced recovery protocols (ERPs) have been used to decrease the physiologic stress and inflammation of surgery using evidence-based principles. ERPs include optimizing patient preparation, creating less trauma using minimally invasive anesthetic and surgical techniques, and regular audit of outcomes. A critical aspect of ERPs is patient engagement in all phases of care, which facilitates effective team function and focused oversight of patient flow through the system. Counseling extends beyond traditional review of surgical risks and benefits, by creating clear daily patient goals, establishing pain management plans, optimizing nutrition, and defining criteria for discharge...
April 2018: Seminars in Pediatric Surgery
Peng Chen, Xiaohu Liu, Garima Goyal, Nhung Thi Tran, James Chin Shing Ho, Yi Wang, Daniel Aili, Bo Liedberg
Localized surface plasmon resonance (LSPR) constitutes a versatile technique for biodetection exploiting the sensitivity of plasmonic nanostructures to small changes in refractive index. The optical shift in the LSPR band caused by molecular in-teractions in the vicinity of the nanostructures are typically < 5 nm and can readily be detected using a spectrophotometer. Widespread use of LSPR based sensors require cost effective devices and would benefit from sensing schemes that enables use of very simple spectrophotometers or even naked eye detection...
March 15, 2018: Analytical Chemistry
Doron Feinsilber, Roberto J Leoni, Duminda Siripala, Julianne Leuck, Katrina A Mears
The pharmacological and medical management of complex chemotherapy regimens are vast and complex, requiring an intimate understanding of physiology, particularly when novel biologic agents are utilized with commonly used regimens. The molecular classification in patients with diffuse large B-cell lymphoma (DLBCL) is multifaceted, particularly with the expansion of novel molecular targets. The pharmacological and medical management of hematologic malignancies with a tendency to have central nervous system (CNS) involvement is complex and requires an understanding of physiology and pharmacology...
January 8, 2018: Curēus
Kevin F Elwood, Robert W Wong
PURPOSE: To describe a case of transient, partial, central retinal artery occlusion with paracentral acute middle maculopathy optical coherence tomography presentation in a young healthy patient after ingestion of the synephrine-containing supplement, Havok. METHODS: Retrospective case report with fundus photography, fluorescein angiography, and optical coherence tomography. RESULTS: A 20-year-old man presented with severe acute vision loss in the right eye...
March 8, 2018: Retinal Cases & Brief Reports
Stylianos Michalakis, Elvir Becirovic, Martin Biel
The first step in vision is the absorption of photons by the photopigments in cone and rod photoreceptors. After initial amplification within the phototransduction cascade the signal is translated into an electrical signal by the action of cyclic nucleotide-gated (CNG) channels. CNG channels are ligand-gated ion channels that are activated by the binding of cyclic guanosine monophosphate (cGMP) or cyclic adenosine monophosphate (cAMP). Retinal CNG channels transduce changes in intracellular concentrations of cGMP into changes of the membrane potential and the Ca2+ concentration...
March 7, 2018: International Journal of Molecular Sciences
Dongmei Lin, Aihua Zhang, Jason Gu, Xiaolei Chen, Qi Wang, Liming Yang, Yongxin Chou, Gongcai Liu, Jingyang Wang
BACKGROUND AND OBJECTIVE: Pulse signals contain a wealth of human physiological and pathological information. How to get full pulse information is especially challenging, and most of the traditional pulse sensors can only get the pulse wave of a single point. This study is aimed at developing a binocular pulse detection system and method to obtain multipoint pulse waves and dynamic three-dimensional pulse shape of the radial artery. METHODS: The proposed pulse detection approach is image-based and implemented by two steps...
March 2018: Computer Methods and Programs in Biomedicine
Claudia Gonzalez Viejo, Sigfredo Fuentes, Kate Howell, Damir D Torrico, Frank R Dunshea
Traditional sensory tests rely on conscious and self-reported responses from participants. The integration of non-invasive biometric techniques, such as heart rate, body temperature, brainwaves and facial expressions can gather more information from consumers while tasting a product. The main objectives of this study were i) to assess significant differences between beers for all conscious and unconscious responses, ii) to find significant correlations among the different variables from the conscious and unconscious responses and iii) to develop a model to classify beers according to liking using only the unconscious responses...
February 28, 2018: Physiology & Behavior
Gadi Lissak
A growing body of literature is associating excessive and addictive use of digital media with physical, psychological, social and neurological adverse consequences. Research is focusing more on mobile devices use, and studies suggest that duration, content, after-dark-use, media type and the number of devices are key components determining screen time effects. Physical health effects: excessive screen time is associated with poor sleep and risk factors for cardiovascular diseases such as high blood pressure, obesity, low HDL cholesterol, poor stress regulation (high sympathetic arousal and cortisol dysregulation), and Insulin Resistance...
February 27, 2018: Environmental Research
Yuri Agrawal, Kevin G Pineault, Yevgeniy R Semenov
Objectives: Vestibular loss is a debilitating condition, and despite its high prevalence in older adults, the quality of life (QoL) burden of vestibular loss in older individuals has not been well-studied. This report quantifies the impact on overall QoL and identifies domains of health most affected. We hypothesize vestibular loss will be associated with impairment in diverse domains of health-related QoL. Study Design: Prospective, case-control study. Methods: A convenience sample of 27 patients age ≥60 years with vestibular physiologic loss was recruited from an academic neurotology clinic...
February 2018: Laryngoscope Investigative Otolaryngology
Wojciech Wieclawek
BACKGROUND: Image segmentation is an essential and non trivial task in computer vision and medical image analysis. Computed tomography (CT) is one of the most accessible medical examination techniques to visualize the interior of a patient's body. Among different computer-aided diagnostic systems, the applications dedicated to kidney segmentation represent a relatively small group. In addition, literature solutions are verified on relatively small databases. The goal of this research is to develop a novel algorithm for fully automated kidney segmentation...
February 27, 2018: Biomedical Engineering Online
Mayur Choudhary, Stephen Safe, Goldis Malek
The aryl hydrocarbon receptor (AhR) is a ligand activated transcription factor, initially discovered for its role in regulating xenobiotic metabolism. There is extensive evidence supporting a multi-faceted role for AhR, modulating physiological pathways important in cell health and disease. Recently we demonstrated that the AhR plays a role in the pathogenesis of age-related macular degeneration (AMD), the leading cause of vision loss in the elderly. We found that loss of AhR exacerbates choroidal neovascular (CNV) lesion formation in a murine model...
February 23, 2018: Biochimica et Biophysica Acta
Zhengchun Wang, Shan Yu, Yu Fu, Tzvetomir Tzvetanov, Yifeng Zhou
Aging-related declines in vision can decrease well-being of the elderly. Concerning early sensory changes as in the primary visual cortex, physiological and behavioral reports seem contradictory. Neurophysiological studies on orientation tuning properties suggested that neuronal changes might come from decreased cortical local inhibition. However, behavioral results either showed no clear deficits in orientation processing in older adults, or proposed stronger surround suppression. Through psychophysical experiments and computational modeling, we resolved these discrepancies by suggesting that lateral inhibition increased in older adults while neuronal orientation tuning widths, related to local inhibition, stayed globally intact across age...
2018: Frontiers in Aging Neuroscience
U Mansmann
BACKGROUND: Over the past 100 years, evidence-based medicine has undergone several fundamental changes. Through the field of physiology, medical doctors were introduced to the natural sciences. Since the late 1940s, randomized and epidemiological studies have come to provide the evidence for medical practice, which led to the emergence of clinical epidemiology as a new field in the medical sciences. Within the past few years, big data has become the driving force behind the vision for having a comprehensive set of health-related data which tracks individual healthcare histories and consequently that of large populations...
February 16, 2018: Zeitschrift Für Rheumatologie
Guofu Shen, Schuyler Link, Sandeep Kumar, Derek M Nusbaum, Dennis Y Tse, Yingbin Fu, Samuel M Wu, Benjamin J Frankfort
Elevated intracranial pressure (ICP) can result in multiple neurologic sequelae including vision loss. Inducible models of ICP elevation are lacking in model organisms, which limits our understanding of the mechanism by which increased ICP impacts the visual system. We adapted a mouse model for the sustained elevation of ICP and tested the hypothesis that elevated ICP impacts the optic nerve and retinal ganglion cells (RGCs). ICP was elevated and maintained for 2 weeks, and resulted in multiple anatomic changes that are consistent with human disease including papilledema, loss of physiologic cupping, and engorgement of the optic nerve head...
February 12, 2018: Scientific Reports
Maesoon Im, Paul Werginz, Shelley Fried
To improve the quality of artificial vision that arises from retinal prostheses, it is important to bring electrically-elicited neural activity more in line with the physiological signaling patterns that arise normally in the healthy retina. Our previous study reported that indirect activation produces a closer match to physiological responses in ON retinal ganglion cells (RGCs) than in OFF cells . This suggests that a preferential activation of ON RGCs would shape the overall retinal response closer to natural signaling...
February 8, 2018: Journal of Neural Engineering
Xinxin You, Min Sun, Jia Li, Chao Bian, Jieming Chen, Yunhai Yi, Hui Yu, Qiong Shi
Mudskippers are the largest group of amphibious teleost fish that are uniquely adapted to live on mudflats. During their successful transition from aqueous life to terrestrial living, these fish have evolved morphological and physiological modifications of aerial vision and olfaction, higher ammonia tolerance, aerial respiration, improved immunological defense against terrestrial pathogens, and terrestrial locomotion using protruded pectoral fins. Comparative genomic and transcriptomic data have been accumulated and analyzed for understanding molecular mechanisms of the terrestrial adaptations...
February 7, 2018: Animals: An Open Access Journal From MDPI
Jeffrey H Plochocki, Tamar Segev, Wade Grow, Margaret I Hall
OBJECTIVE: A complete and accurate understanding of extraocular muscle function is important to the veterinary care of the avian eye. This is especially true for birds of prey, which rely heavily on vision for survival and yet are prone to ocular injury and disease. To better understand the function of extraocular muscles in birds of prey, we studied extraocular muscle architecture grossly and histologically. ANIMALS STUDIED: This sample was composed of two each of the following species: red-tailed hawk (Buteo jamaicensis), Harris's hawk (Parabuteo unicinctus), great horned owl (Bubo virginianus), and barn owl (Tyto alba)...
February 6, 2018: Veterinary Ophthalmology
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