keyword
MENU ▼
Read by QxMD icon Read
search

physiology of vision

keyword
https://www.readbyqxmd.com/read/28318721/-physiology-of-the-visual-retinal-signal-from-phototransduction-to-the-visual-cycle
#1
REVIEW
C Salesse
The retinal photoreceptors (rods and cones) are responsible for light absorption and transduction of the signal, which is transmitted to the other retinal nerve cells and then to the brain. The chromophore of visual pigments of rods and cones is a particular isomer of a vitamin A derivative. Light absorption by this chromophore leads to its isomerization and to a phototransduction cascade, which results in photoreceptor hyperpolarization and cessation of glutamate secretion at their synaptic terminals. Phototransduction of cones and rods differs in their signal amplification and inactivation, which is consistent with their respective functions...
March 17, 2017: Journal Français D'ophtalmologie
https://www.readbyqxmd.com/read/28286868/a-basis-for-comparison-sensitive-authentication-of-stem-cell-derived-rpe-using-physiological-responses-of-intact-rpe-monolayers
#2
Kiyoharu J Miyagishima, Qin Wan, Sheldon S Miller, Kapil Bharti
The retinal pigment epithelium (RPE) is a monolayer of highly specialized cells that help maintain the chemical composition of its surrounding subretinal and choroidal extracellular spaces. Retinal cells (photoreceptors in particular), RPE, and choroidal endothelial cells together help ensure a homeostatically stable metabolic environment with exquisitely sensitive functional responses to light. Aging and disease of the RPE impairs its supportive functions contributing to the progressive loss of photoreceptors and vision...
2017: Stem Cell and Translational Investigation
https://www.readbyqxmd.com/read/28277392/impaired-kidney-function-and-associated-factors-among-rural-adults-with-disabilities-in-taiwan
#3
Chu-Yeh Chen, Wen-Nan Chiu, Yu-Chen Lin, Sui-Hwi Jane, Hsin-Hung Chiang, Mei-Yen Chen
BACKGROUND: The results of numerous studies indicate that people with disabilities seek more healthcare than those who are not disabled, particularly for conditions such as chronic kidney disease, cardiovascular disease, and obesity. However, little is known about the incidence of impaired kidney function and its associated factors among adults with disabilities in Taiwan. PURPOSE: The aim of this study was to explore the prevalence and factors associated with impaired kidney function among adults with disabilities...
April 2017: Journal of Nursing Research: JNR
https://www.readbyqxmd.com/read/28263770/human-physiological-responses-to-wooden-indoor-environment
#4
Xi Zhang, Zhiwei Lian, Yong Wu
Previous studies are mainly focused on non-wooden environments, whereas few are concerned with wooden ones. How wooden indoor environments impact the physiology of the occupants is still unclear. The purpose of this study was to explore the distinct physiological responses to wooden and non-wooden indoor environments, assessed by physiological parameters tests including blood pressure, electrocardiogram measurements, electro-dermal activity, oxyhemoglobin saturation, skin temperature, and near distance vision...
March 2, 2017: Physiology & Behavior
https://www.readbyqxmd.com/read/28258307/nutrition-for-diabetic-retinopathy-plummeting-the-inevitable-threat-of-diabetic-vision-loss
#5
REVIEW
Yashodhara Sharma, Sandeep Saxena, Arvind Mishra, Anita Saxena, Shankar Madhav Natu
Diabetic retinopathy (DR) is among the leading causes of preventable blindness. Hyperglycemia, hypertension, hyperlipidemia and anemia majorly predispose its pathogenesis. The current treatment modalities of DR include laser photocoagulation therapy, intravitreal corticosteroids, intravitreal anti-vascular endothelial growth factor (VEGF) agents and vitreo-retinal surgery which are costly, highly invasive, unproven for prolonged use and opted in advanced stages of DR. By then retina already encounters a vast damage...
March 3, 2017: European Journal of Nutrition
https://www.readbyqxmd.com/read/28254455/early-processing-in-primary-visual-cortex-is-necessary-for-conscious-and-unconscious-vision-while-late-processing-is-necessary-only-for-conscious-vision-in-neurologically-healthy-humans
#6
Mikko Hurme, Mika Koivisto, Antti Revonsuo, Henry Railo
The neural mechanisms underlying conscious and unconscious visual processes remain controversial. Blindsight patients may process visual stimuli unconsciously despite their V1 lesion, promoting anatomical models, which suggest that pathways bypassing the V1 support unconscious vision. On the other hand, physiological models argue that the major geniculostriate pathway via V1 is involved in both unconscious and conscious vision, but in different time windows and in different types of neural activity. According to physiological models, feedforward activity via V1 to higher areas mediates unconscious processes whereas feedback loops of recurrent activity from higher areas back to V1 support conscious vision...
February 22, 2017: NeuroImage
https://www.readbyqxmd.com/read/28242737/unchanging-visions-the-effects-and-limitations-of-ocular-stillness
#7
REVIEW
Susana Martinez-Conde, Stephen L Macknik
Scientists have pondered the perceptual effects of ocular motion, and those of its counterpart, ocular stillness, for over 200 years. The unremitting 'trembling of the eye' that occurs even during gaze fixation was first noted by Jurin in 1738. In 1794, Erasmus Darwin documented that gaze fixation produces perceptual fading, a phenomenon rediscovered in 1804 by Ignaz Paul Vital Troxler. Studies in the twentieth century established that Jurin's 'eye trembling' consisted of three main types of 'fixational' eye movements, now called microsaccades (or fixational saccades), drifts and tremor...
April 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28218404/topical-medication-instillation-techniques-for-glaucoma
#8
REVIEW
Li Xu, Xuemei Wang, Meijing Wu
BACKGROUND: Glaucoma is a leading cause of irreversible blindness worldwide and the second most common cause of blindness after cataracts. The primary treatment for glaucoma aims to lower intraocular pressure (IOP) with the use of topical medicines. Topical medication instillation techniques, such as eyelid closure and nasolacrimal occlusion when instilling drops, have been proposed as potential methods to increase ocular absorption and decrease systemic absorption of the drops. OBJECTIVES: To investigate the effectiveness of topical medication instillation techniques compared with usual care or another method of instillation of topical medication in the management of glaucoma or ocular hypertension...
February 20, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/28212157/current-approaches-to-myopia-control
#9
Seo Wei Leo
PURPOSE OF REVIEW: Myopia is a global problem, being particularly prevalent in the urban areas of east and southeast Asia. In addition to the direct economic and social burdens, associated ocular complications may lead to substantial vision loss. With prevalence of myopia above 80% and high myopia over 20%, it is crucial to control myopia. The aim of this review to is provide an update on the interventions to slow the onset of myopia and retard its progression. RECENT FINDINGS: The epidemic of myopia is characterized by increasingly early onset, combined with high myopia progression rates...
February 15, 2017: Current Opinion in Ophthalmology
https://www.readbyqxmd.com/read/28195004/physiological-modeling-for-detecting-degree-of-perception-of-a-color-deficient-person
#10
T Rajalakshmi, Shanthi Prince
Physiological modeling of retina plays a vital role in the development of high-performance image processing methods to produce better visual perception. People with normal vision have an ability to discern different colors. The situation is different in the case of people with color blindness. The aim of this work is to develop a human visual system model for detecting the level of perception of people with red, green and blue deficiency by considering properties like luminance, spatial and temporal frequencies...
February 1, 2017: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
https://www.readbyqxmd.com/read/28193822/comparative-system-identification-of-flower-tracking-performance-in-three-hawkmoth-species-reveals-adaptations-for-dim-light-vision
#11
Anna L Stöckl, Klara Kihlström, Steven Chandler, Simon Sponberg
Flight control in insects is heavily dependent on vision. Thus, in dim light, the decreased reliability of visual signal detection also prompts consequences for insect flight. We have an emerging understanding of the neural mechanisms that different species employ to adapt the visual system to low light. However, much less explored are comparative analyses of how low light affects the flight behaviour of insect species, and the corresponding links between physiological adaptations and behaviour. We investigated whether the flower tracking behaviour of three hawkmoth species with different diel activity patterns revealed luminance-dependent adaptations, using a system identification approach...
April 5, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28193821/insect-photoreceptor-adaptations-to-night-vision
#12
REVIEW
Anna Honkanen, Esa-Ville Immonen, Iikka Salmela, Kyösti Heimonen, Matti Weckström
Night vision is ultimately about extracting information from a noisy visual input. Several species of nocturnal insects exhibit complex visually guided behaviour in conditions where most animals are practically blind. The compound eyes of nocturnal insects produce strong responses to single photons and process them into meaningful neural signals, which are amplified by specialized neuroanatomical structures. While a lot is known about the light responses and the anatomical structures that promote pooling of responses to increase sensitivity, there is still a dearth of knowledge on the physiology of night vision...
April 5, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28193817/behavioural-and-physiological-limits-to-vision-in-mammals
#13
REVIEW
Greg D Field, Alapakkam P Sampath
Human vision is exquisitely sensitive-a dark-adapted observer is capable of reliably detecting the absorption of a few quanta of light. Such sensitivity requires that the sensory receptors of the retina, rod photoreceptors, generate a reliable signal when single photons are absorbed. In addition, the retina must be able to extract this information and relay it to higher visual centres under conditions where very few rods signal single-photon responses while the majority generate only noise. Critical to signal transmission are mechanistic optimizations within rods and their dedicated retinal circuits that enhance the discriminability of single-photon responses by mitigating photoreceptor and synaptic noise...
April 5, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28176941/bioglass-implant-coating-interactions-in-synthetic-physiological-fluids-with-varying-degrees-of-biomimicry
#14
A C Popa, G E Stan, M A Husanu, I Mercioniu, L F Santos, H R Fernandes, Jmf Ferreira
Synthetic physiological fluids are currently used as a first in vitro bioactivity assessment for bone grafts. Our understanding about the interactions taking place at the fluid-implant interface has evolved remarkably during the last decade, and does not comply with the traditional International Organization for Standardization/final draft International Standard 23317 protocol in purely inorganic simulated body fluid. The advances in our knowledge point to the need of a true paradigm shift toward testing physiological fluids with enhanced biomimicry and a better understanding of the materials' structure-dissolution behavior...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28155698/the-biomechanical-significance-of-pulley-on-binocular-vision
#15
Hongmei Guo, Zhipeng Gao, Weiyi Chen
BACKGROUND: Pulleys have been reported as the functional origins of the rectus extraocular muscles (EOMs). However, biomechanical significance of pulleys on binocular vision has not been reported. METHODS: Three eye movement models, i.e., non-pulley model, passive-pulley model, and active-pulley model, are used to simulate the horizontal movement of the eyes from the primary position to the left direction in the range of 1°-30°. The resultant forces of six EOMs along both orthogonal directions (i...
December 28, 2016: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28148613/delirium-in-trauma-patients-prevalence-and-predictors
#16
Kathryn T Von Rueden, Breighanna Wallizer, Paul Thurman, Karen McQuillan, Tiffany Andrews, Jennifer Merenda, Heesook Son
BACKGROUND: Delirium is associated with increased mortality, morbidity, hospital costs, and postdischarge cognitive dysfunction. Most research focuses on nontrauma patients receiving mechanical ventilation in the intensive care unit. OBJECTIVES: To determine the prevalence and predictors of delirium in trauma patients residing in intensive and intermediate care units of an academic medical center. METHODS: Trauma patients were screened for delirium by using the Confusion Assessment Method for the Intensive Care Unit...
February 2017: Critical Care Nurse
https://www.readbyqxmd.com/read/28146554/fundamental-activity-constraints-lead-to-specific-interpretations-of-the-connectome
#17
Jannis Schuecker, Maximilian Schmidt, Sacha J van Albada, Markus Diesmann, Moritz Helias
The continuous integration of experimental data into coherent models of the brain is an increasing challenge of modern neuroscience. Such models provide a bridge between structure and activity, and identify the mechanisms giving rise to experimental observations. Nevertheless, structurally realistic network models of spiking neurons are necessarily underconstrained even if experimental data on brain connectivity are incorporated to the best of our knowledge. Guided by physiological observations, any model must therefore explore the parameter ranges within the uncertainty of the data...
February 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28138125/face-transplant-in-an-advanced-neurofibromatosis-type-1-patient
#18
Łukasz Krakowczyk, Adam Maciejewski, Cezary Szymczyk, Krzysztof Oleś, Stanisław Półtorak
BACKGROUND The human face is a one-of-a-kind structure with unique morphology, complexity, and function, in which different subunits are not even similar to other parts of the body. Therefore, extended complex deficits of the face are usually difficult to reconstruct, and autologous tissue restoration is generally not able to give a satisfactory aesthetic and functional outcome. The main goal of face allotransplantation is to restore symmetry, contour, and appearance as well as function of the face, especially control of orbicularis oculi and oris muscle physiology...
January 31, 2017: Annals of Transplantation: Quarterly of the Polish Transplantation Society
https://www.readbyqxmd.com/read/28135308/individual-objective-and-subjective-fixation-disparity-in-near-vision
#19
Wolfgang Jaschinski
Binocular vision refers to the integration of images in the two eyes for improved visual performance and depth perception. One aspect of binocular vision is the fixation disparity, which is a suboptimal condition in individuals with respect to binocular eye movement control and subsequent neural processing. The objective fixation disparity refers to the vergence angle between the visual axes, which is measured with eye trackers. Subjective fixation disparity is tested with two monocular nonius lines which indicate the physical nonius separation required for perceived alignment...
2017: PloS One
https://www.readbyqxmd.com/read/28113186/epidural-spinal-stimulation-to-improve-bladder-bowel-and-sexual-function-in-individuals-with-spinal-cord-injuries-a-framework-for-clinical-research
#20
Roderic I Pettigrew, William J Heetderks, Christine A Kelley, Grace C Y Peng, Steven H Krosnick, Lyn B Jakeman, Katharine D Egan, Michael Marge
While some recent studies that apply epidural spinal cord stimulation (SCS) have demonstrated a breakthrough in improvement of the health and quality of the life of persons with spinal cord injury (SCI), the numbers of people who have received SCS are small. This is in sharp contrast to the thousands of persons worldwide living with SCI who have no practical recourse or hope of recovery of lost functions. Thus, the vision is to understand the full potential of this new intervention and to determine if it is safe and effective in a larger cohort, and if it is scalable so that it can be made available to all those who might benefit...
February 2017: IEEE Transactions on Bio-medical Engineering
keyword
keyword
119185
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"