Publications by authors named "Heywood C"

The specificity and effectiveness of eye-movement training to remedy impaired visual exploration and reading with particular consideration of age and co-morbidity was tested in a group of 97 patients with unilateral homonymous hemianopia using a single subject /n-of-1 design. Two groups received either scanning training followed by reading training, or . The third group acted as a control group and received non-specific detailed advice, followed by training of scanning and reading.

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What is the long-term trajectory of semantic memory deficits in patients who have suffered structural brain damage? Memory is, per definition, a changing faculty. The traditional view is that after an initial recovery period, the mature human brain has little capacity to repair or reorganize. More recently, it has been suggested that the central nervous system may be more plastic with the ability to change in neural structure, connectivity, and function.

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Blindsight refers to the observation of residual visual abilities in the hemianopic field of patients without a functional V1. Given the within- and between-subject variability in the preserved abilities and the phenomenal experience of blindsight patients, the fine-grained description of the phenomenon is still debated. Here we tested a patient with established "perceptual" and "attentional" blindsight (c.

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Translucence is an important property of natural materials, and human observers are adept at perceiving changes in translucence. Perceptions of different material properties appear to arise from different cortical regions, and it is therefore plausible that the perception of translucence is dependent on specialised regions, separate from those important for colour and texture processing. To test for anatomical independence between areas necessary for colour, texture and translucence perception we assessed translucency perception in a cortically colour blind observer, who performs at chance on tasks of colour and texture discrimination.

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Background: The RAPPER II study investigates the feasibility, safety and acceptability of using the REX self-stabilising robotic exoskeleton in people with spinal cord injury (SCI) who are obligatory wheelchair users. Feasibility is assessed by the completion of transfer into the REX device, competency in achieving autonomous control and completion of upper body exercise in an upright position in the REX device. Safety is measured by the occurrence of serious adverse events.

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Visual neuroscience is concerned with the neurobiological foundations of visual perception, that is, the morphological, physiological, and functional organization of the visual brain and its co-operative partners. One important approach for understanding the functional organization of the visual brain is the study of visual perception from the pathological perspective. The study of patients with focal injury to the visual brain allows conclusions about the representation of visual perceptual functions in the framework of association and dissociation of functions.

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The effective capture of outcome measures in the healthcare setting can be traced back to Florence Nightingale's investigation of the in-patient mortality of soldiers wounded in the Crimean war in the 1850s. Only relatively recently has the formalised collection of outcomes data into Registries been recognised as valuable in itself. With the advent of surgeon league tables and a move towards value based health care, individuals are being driven to collect, store and interpret data.

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Our perception of regional irregularity, an example of which is orientation variance, seems effortless when we view two patches of texture that differ in this attribute. Little is understood, however, of how the visual system encodes a regional statistic like orientation variance, but there is some evidence to suggest that it is directly encoded by populations of neurons tuned broadly to high or low levels. The present study shows that selective adaptation to low or high levels of variance results in a perceptual aftereffect that shifts the perceived level of variance of a subsequently viewed texture in the direction away from that of the adapting stimulus (Experiments 1 and 2).

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Attention and awareness are closely related phenomena, but recent evidence has shown that not all attended stimuli give rise to awareness. Controversy still remains over whether, and the extent to which, a dissociation between attention and awareness encompasses all forms of attention. For example, it has been suggested that attention without awareness is more readily demonstrated for voluntary, endogenous attention than its reflexive, exogenous counterpart.

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The significance of early and sporadic reports in the 19th century of impairments of motion vision following brain damage was largely unrecognized. In the absence of satisfactory post-mortem evidence, impairments were interpreted as the consequence of a more general disturbance resulting from brain damage, the location and extent of which was unknown. Moreover, evidence that movement constituted a special visual perception and may be selectively spared was similarly dismissed.

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The illumination of a scene strongly affects our perception of objects in that scene, e.g., the pages of a book illuminated by candlelight will appear quite yellow relative to other types of artificial illuminants.

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Background: The small molecule NSC676914A was previously identified as an NF-κB inhibitor in TPA-stimulated HEK293 cells (Mol Can Ther 8:571-581, 2009). We hypothesized that this effect would also be seen in ovarian cancer cells, and serve as its mechanism of cytotoxicity. OVCAR3 and HEK293 cell lines stably containing a NF-κB luciferase reporter gene were generated.

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Public-supply wells with long screens in alluvial aquifers can produce waters of differing quality from different depths. Seasonal changes in quality are linked to seasonal changes in pumping rates that influence the distribution of flow into the well screens under pumping conditions and the magnitude and direction of intraborehole flow within the wells under ambient conditions. Groundwater flow and transport simulations with MODFLOW and MT3DMS were developed to quantify the effects of changes in average seasonal pumping rates on intraborehole flow and water quality at two long-screened, public-supply wells, in Albuquerque, New Mexico and Modesto, California, where widespread pumping has altered groundwater flow patterns.

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Objective: Beyond visual field defects, patients with hemianopia have been suggested to perceive horizontal visual space in a distorted manner. However, the pattern of these distortions remained debatable. The aim of this study was to estimate the geometry of the visual representation of space in hemianopia using an auditory marker.

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The phenotype, or observable trait of interest, is at the core of studies identifying associated genetic variants and their functional pathways, as well as diagnostics. Yet, despite remarkable technological developments in genotyping and progress in genetic research, relatively little attention has been paid to the equally important issue of phenotype. This is especially true for disc degeneration-related disorders, and the concept of degenerative disc disease, in particular, where there is little consensus or uniformity of definition.

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Attention and awareness are often considered to be related. Some forms of attention can, however, facilitate the processing of stimuli that remain unseen. It is unclear whether this dissociation extends beyond selection on the basis of primitive properties, such as spatial location, to situations in which there are more complex bases for attentional selection.

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Reading and visual exploration impairments in unilateral homonymous visual field disorders are frequent and disabling consequences of acquired brain injury. Compensatory therapies have been developed, which allow patients to regain sufficient reading and visual exploration performance through systematic oculomotor training. However, it is still unclear whether the reading and visual exploration impairments require specific compensatory training for their improvement.

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Reading skills are core competencies in children's readiness to learn and may be particularly important for children in foster care, who are at risk for academic difficulties and higher rates of special education placement. In this study, prereading skills (phonological awareness, alphabetic knowledge, and oral language ability) and kindergarten performance of 63 children in foster care were examined just prior to and during the fall of kindergarten. The children exhibited prereading deficits with average prereading scores that fell at the 30(th) to 40(th) percentile.

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Regions of visual texture can be automatically segregated from one another when they abut but also discriminated from one another if they are separated in space or time. A difference in mean orientation between two textures serves to facilitate their segmentation, whereas a difference in orientation variance does not. The present study further supports this notion, by replicating the findings of Wolfson and Landy (1998) in showing that judgments (odd-one-out) made for textures that differ in mean orientation were more accurate (and more rapid) when the textures were abutting than when separated, whereas judgments of variance were made no more accurately for abutting relative to separated textures.

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Purpose: To determine the ability of magnetic resonance imaging (MRI) to characterize the stability of osteochondritis dissecans (OCD) fragments in juveniles.

Methods: Twenty-eight consecutive patients underwent surgery for OCD between 2004 and 2008. Of these, 23 patients had adequate preoperative imaging.

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Patients with postchiasmatic visual field defects often show a contralesional bias towards the scotoma in line bisection or when indicating their visual subjective straight ahead (VSSA). Recent evidence suggests a retinotopic misrepresentation of visual space in patients with homonymous quadrantanopia (HQ). We therefore assessed in the present study whether patients with HQ show an oblique shift of their VSSA towards their scotoma, in addition to the known bias in horizontal line bisection.

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Previous neuroimaging research suggests that although object shape is analyzed in the lateral occipital cortex, surface properties of objects, such as color and texture, are dealt with in more medial areas, close to the collateral sulcus (CoS). The present study sought to determine whether there is a single medial region concerned with surface properties in general or whether instead there are multiple foci independently extracting different surface properties. We used stimuli varying in their shape, texture, or color, and tested healthy participants and 2 object-agnosic patients, in both a discrimination task and a functional MR adaptation paradigm.

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Real-life visual object recognition requires the processing of more than just geometric (shape, size, and orientation) properties. Surface properties such as color and texture are equally important, particularly for providing information about the material properties of objects. Recent neuroimaging research suggests that geometric and surface properties are dealt with separately within the lateral occipital cortex (LOC) and the collateral sulcus (CoS), respectively.

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Reading and visual exploration impairments in unilateral homonymous hemianopia are well-established clinical phenomena. Spontaneous adaptation of eye-movements to the visual field defect leads to improved reading and visual exploration performance. Yet, it is still unclear whether oculomotor adaptation to visual field loss is task-specific or whether there is a transfer of adaptation-related improvements between reading and visual exploration.

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