Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
9,625
result(s) for
"Vision, Ocular"
Sort by:
Sight unseen : an exploration of conscious and unconscious vision
Vision, more than any other sense, dominates our mental life. Our conscious visual experience of the world is so rich and detailed that we can hardly distinguish it from the real thing. But as Goodale and Milner make clear in their prize-winning book, Sight Unseen, our visual experience of the world is not all there is to vision. Some of the most important things that vision does for us never reach our consciousness at all. In this updated and extended new edition, Goodale and Milner explore one of the most extraordinary neurological cases of recent years--one that profoundly changed scientific views on the visual brain. It is the story of Dee Fletcher--a young woman who became blind to shape and form as a result of brain damage. Dee was left unable to recognize objects or even tell one simple geometric shape from another. As events unfolded, however, Goodale and Milner found that Dee wasn't in fact blind -- she just didn't know that she could see. They showed, for example, that Dee could reach out and grasp objects with amazing dexterity, despite being unable to perceive their shape, size, or orientation. Taking us on a journey into the unconscious brain, the two scientists who made this incredible discovery tell the amazing story of their work, and the surprising conclusion they were forced to reach. Written to be accessible to students and popular science readers, this book is a fascinating illustration of the power of the 'unconscious' mind.
Book
Vision using multiple distinct rod opsins in deep-sea fishes
Vertebrate vision is accomplished through light-sensitive photopigments consisting of an opsin protein bound to a chromophore. In dim light, vertebrates generally rely on a single rod opsin [rhodopsin 1 (RH1)] for obtaining visual information. By inspecting 101 fish genomes, we found that three deep-sea teleost lineages have independently expanded their RH1 gene repertoires. Among these, the silver spinyfin (Diretmus argenteus) stands out as having the highest number of visual opsins in vertebrates (two cone opsins and 38 rod opsins). Spinyfins express up to 14 RH1s (including the most blueshifted rod photopigments known), which cover the range of the residual daylight as well as the bioluminescence spectrum present in the deep sea. Our findings present molecular and functional evidence for the recurrent evolution of multiple rod opsin–based vision in vertebrates.
Journal Article
Reprogramming to recover youthful epigenetic information and restore vision
Ageing is a degenerative process that leads to tissue dysfunction and death. A proposed cause of ageing is the accumulation of epigenetic noise that disrupts gene expression patterns, leading to decreases in tissue function and regenerative capacity
1
–
3
. Changes to DNA methylation patterns over time form the basis of ageing clocks
4
, but whether older individuals retain the information needed to restore these patterns—and, if so, whether this could improve tissue function—is not known. Over time, the central nervous system (CNS) loses function and regenerative capacity
5
–
7
. Using the eye as a model CNS tissue, here we show that ectopic expression of
Oct4
(also known as
Pou5f1
),
Sox2
and
Klf4
genes (OSK) in mouse retinal ganglion cells restores youthful DNA methylation patterns and transcriptomes, promotes axon regeneration after injury, and reverses vision loss in a mouse model of glaucoma and in aged mice. The beneficial effects of OSK-induced reprogramming in axon regeneration and vision require the DNA demethylases TET1 and TET2. These data indicate that mammalian tissues retain a record of youthful epigenetic information—encoded in part by DNA methylation—that can be accessed to improve tissue function and promote regeneration in vivo.
Expression of three Yamanaka transcription factors in mouse retinal ganglion cells restores youthful DNA methylation patterns, promotes axon regeneration after injury, and reverses vision loss in a mouse model of glaucoma and in aged mice, suggesting that mammalian tissues retain a record of youthful epigenetic information that can be accessed to improve tissue function.
Journal Article
The genome of the model beetle and pest Tribolium castaneum
Tribolium castaneum is a member of the most species-rich eukaryotic order, a powerful model organism for the study of generalized insect development, and an important pest of stored agricultural products. We describe its genome sequence here. This omnivorous beetle has evolved the ability to interact with a diverse chemical environment, as shown by large expansions in odorant and gustatory receptors, as well as P450 and other detoxification enzymes. Development in Tribolium is more representative of other insects than is Drosophila, a fact reflected in gene content and function. For example, Tribolium has retained more ancestral genes involved in cellcell communication than Drosophila, some being expressed in the growth zone crucial for axial elongation in short-germ development. Systemic RNA interference in T. castaneum functions differently from that in Caenorhabditis elegans, but nevertheless offers similar power for the elucidation of gene function and identification of targets for selective insect control.
Journal Article
The effect of stroboscopic vision training on the performance of elite curling athletes
The aim of the study was to investigate the impacts of four weeks of stroboscopic vision training (SVT) and four weeks of temporal feedback training (TFT) on elite curling athletes’ duration judgment, as well as stone delivery performance (delivery speed control and accuracy). Thirty national-level curling athletes were selected as participants and randomly assigned to either the SVT group (wearing stroboscopic glasses: the strobe frequencies increased weekly from Level 1 to Level 4.), the TFT group (using a timing system to provide feedback on stone delivery time), or a control group. Apart from the differences in training methods, the intervention programme was identical across the three groups, with each group performing stone delivery training three times per week for 40 min per session. The training regimen consisted of a ‘ladder’ drill targeting the house (effective zones 4–10), with the sequence of training increasing and then decreasing in complexity. Repeated measures ANOVA (3 × 2) and post-hoc tests (Bonferroni) were used to analyse the effects of different training methods. The results showed that the four-week training intervention produced significant interactions in duration judgment (
p
= 0.005,
f
= 0.692) and accuracy (
p
= 0.001,
f
= 0.805). SVT significantly improved duration judgment (
p
< 0.001,
d
= 2.374) and delivery speed control (
p
= 0.011,
d
= 1.421). TFT significantly improved delivery accuracy (
p
= 0.015,
d
= 1.364). Four weeks of SVT and TFT both improved duration judgment, curling speed control performance among elite curling athletes. In terms of accuracy improvement, four weeks of TFT yielded greater benefits than SVT.
Journal Article
Ultrafast structural changes direct the first molecular events of vision
Vision is initiated by the rhodopsin family of light-sensitive G protein-coupled receptors (GPCRs)
1
. A photon is absorbed by the 11-
cis
retinal chromophore of rhodopsin, which isomerizes within 200 femtoseconds to the all-
trans
conformation
2
, thereby initiating the cellular signal transduction processes that ultimately lead to vision. However, the intramolecular mechanism by which the photoactivated retinal induces the activation events inside rhodopsin remains experimentally unclear. Here we use ultrafast time-resolved crystallography at room temperature
3
to determine how an isomerized twisted all
-trans
retinal stores the photon energy that is required to initiate the protein conformational changes associated with the formation of the G protein-binding signalling state. The distorted retinal at a 1-ps time delay after photoactivation has pulled away from half of its numerous interactions with its binding pocket, and the excess of the photon energy is released through an anisotropic protein breathing motion in the direction of the extracellular space. Notably, the very early structural motions in the protein side chains of rhodopsin appear in regions that are involved in later stages of the conserved class A GPCR activation mechanism. Our study sheds light on the earliest stages of vision in vertebrates and points to fundamental aspects of the molecular mechanisms of agonist-mediated GPCR activation.
One picosecond after photoactivation, isomerized retinal pulls away from half of its numerous interactions with its binding pocket, and the excess of the photon energy is released through an anisotropic protein breathing motion in the direction of the extracellular space.
Journal Article
ISCEV standard for clinical visual evoked potentials: (2016 update)
Visual evoked potentials (VEPs) can provide important diagnostic information regarding the functional integrity of the visual system. This document updates the ISCEV standard for clinical VEP testing and supersedes the 2009 standard. The main changes in this revision are the acknowledgment that pattern stimuli can be produced using a variety of technologies with an emphasis on the need for manufacturers to ensure that there is no luminance change during pattern reversal or pattern onset/offset. The document is also edited to bring the VEP standard into closer harmony with other ISCEV standards. The ISCEV standard VEP is based on a subset of stimulus and recording conditions that provide core clinical information and can be performed by most clinical electrophysiology laboratories throughout the world. These are: (1) Pattern-reversal VEPs elicited by checkerboard stimuli with large 1 degree (°) and small 0.25° checks. (2) Pattern onset/offset VEPs elicited by checkerboard stimuli with large 1° and small 0.25° checks. (3) Flash VEPs elicited by a flash (brief luminance increment) which subtends a visual field of at least 20°. The ISCEV standard VEP protocols are defined for a single recording channel with a midline occipital active electrode. These protocols are intended for assessment of the eye and/or optic nerves anterior to the optic chiasm. Extended, multi-channel protocols are required to evaluate postchiasmal lesions.
Journal Article
AAV cis-regulatory sequences are correlated with ocular toxicity
Adeno-associated viral vectors (AAVs) have become popular for gene therapy, given their many advantages, including their reduced inflammatory profile compared with that of other viruses. However, even in areas of immune privilege such as the eye, AAV vectors are capable of eliciting host-cell responses. To investigate the effects of such responses on several ocular cell types, we tested multiple AAV genome structures and capsid types using subretinal injections in mice. Assays of morphology, inflammation, and physiology were performed. Pathological effects on photoreceptors and the retinal pigment epithelium (RPE) were observed. Müller glia and microglia were activated, and the proinflammatory cytokines TNF-α and IL-1β were up-regulated. There was a strong correlation between cisregulatory sequences and toxicity. AAVs with any one of three broadly active promoters, or an RPE-specific promoter, were toxic, while AAVs with four different photoreceptor-specific promoters were not toxic at the highest doses tested. There was little correlation between toxicity and transgene, capsid type, preparation method, or cellular contaminants within a preparation. The toxic effect was dose-dependent, with the RPE being more sensitive than photoreceptors. Our results suggest that ocular AAV toxicity is associated with certain AAV cis-regulatory sequences and/or their activity and that retinal damage occurs due to responses by the RPE and/or microglia. By applying multiple, sensitive assays of toxicity, AAV vectors can be designed so that they can be used safely at high dose, potentially providing greater therapeutic efficacy.
Journal Article