The sudden onset of a cue triggers visual attention, which then enhances visual processing in the zone near the cue. This enhancement causes a motion illusion in subsequent stimuli presented near the ...cue. At greater separations from the cue, the illusory motion reverses direction, indicating prolonged processing speed. Measurements of the strength and direction of illusory motion at increasing separations from the cue reveal an attentional ‘perceptive field’ with an excitatory center at the locus cued and an inhibitory surround subtending the remaining visual field. These findings help explain the traditional attentional ‘benefits’ and ‘costs’ of attention.
Robust visual attentional responses are produced by the sudden onset of a visual cue, but the properties of cues that best elicit an attentional response are not fully known. We used the line-motion ...illusion (Hikosaka et al., 1991) to investigate the optimal cue properties that evoke visual attention. We found that visual attention is driven primarily by the luminance contrast of the cue. Furthermore, by manipulating the spatial, chromatic, and contrast properties of cues, we found that magnocellular (M) stream biased cues always override the response to parvocellular (P) stream biased cues, even when the P stream biased cues are presented first. Our data suggest that cues that preferentially excite the M pathway predominantly capture visual attention.
Visual attention has been defined by different researchers and clinicians in a variety of ways that are sometimes conflicting or confusing. This paper will provide a unified definition of visual ...attention, as well as a putative neurophysiological mechanism that is consistent with this unified definition. In addition, recent data on the mechanisms of visual attention will be presented, including its spatial organization and temporal dependencies, as well as the role of parallel visual pathways in its activation.
Low vision rehabilitation is rapidly growing as a specialty practice for occupational therapists. This growth requires practical, evidence-based information on the evaluation and treatment of the ...effects of low vision on occupational performance. Responding to this need, Low Vision Rehabilitation: A Practical Guide for Occupational Therapists blends standards of practice that have been developed over 50 years by low vision therapists and optometrists, with the latest scientific research and the unique perspective of occupational therapists. Low Vision Rehabilitation presents an emerging model in which occupational therapists practice as part of a team of vision rehabilitation professionals serving adults with low vision. Occupational therapists offer a unique contribution to the vision rehabilitation team, with a focus on meaningful occupational goals, the incorporation of occupation into therapy, and the orchestration of environmental, social, and non-visual personal factors into a treatment plan. Mitchell Scheiman, Maxine Scheiman, and Stephen Whittaker have developed a practical and straightforward text outlining an evaluation approach to interventions that focus on recovering occupational performance in adults. Special featuresIncorporates concepts from the AOTA Occupational Therapy Practice Framework: Domain and ProcessProvides most of the core knowledge required for the ACVREP low vision certification examination and AOTA specialty certification in low visionIncludes an occupational therapy vision rehabilitation evaluation consisting of four components: occupational profile/case history, evaluation of visual factors, environmental evaluation, evaluation of occupational performanceEmphasizes intervention and low vision rehabilitation treatment including modification of the environment, use of non-optical assistive devices, use of optical devices, and use of computer technologyProvides valuable information on how to start an independent practice in low vision rehabilitationIncludes chapters on diabetic management and electronic assistive technologyIncludes access to a companion website with printable forms and additional resources with text purchaseWritten by authors who are optometrists, occupational therapists, researchers, and certified low vision therapists (CLVT), Low Vision Rehabilitation employs an interdisciplinary perspective that is unique, practical, and credible. A Doody's Core Title Selection!
Recent research in reading disability has discovered that at least some reading-disabled subjects have deficits in their magnocellular (M) visual pathways. However, the mechanism by which M pathway ...deficits affect reading has not been addressed. Abnormal attention has long been known to be associated with reading-disabled individuals, and new research in visual attention has determined that transient visual attention is dominated by M-stream inputs. The purpose of this study was to determine whether visual attention might be the mechanism through which a faulty M pathway could produce visual deficits in reading-disabled subjects. Spatiotemporal attentional response functions were measured using the Line Motion Illusion and compared in normal and disabled readers. Specific abnormalities in the visual attention mechanisms of disabled readers were found which might suggest mechanisms by which reading could be affected by a deficient M stream.
We examined whether the decline in motion sensitivity in the elderly is equivalent for different visual field locations.
High velocity (28 degrees/s) random dot kinematograms (RDK's) were used to ...measure direction discrimination thresholds for 5 locations in the visual field (1 position centered on fixation and 4 locations each centered 18 degrees from fixation in the nasal, temporal, superior, and inferior quadrants). Differential luminance sensitivity was assessed by automated perimetry. Younger (N = 15, mean age = 22.9 +/- 1.3 years) and older (N = 13, mean age = 66.6 +/- 4.5 years) subjects were studied.
Motion sensitivity varied with test location for both younger and older subjects, but sensitivity was significantly lower in older individuals. The largest age-related reduction in sensitivity was in the central location, whereas the smallest decline was in the superior position. No significant correlations between motion and differential luminance sensitivity were evident.
There is a significant age-related deterioration in visual sensitivity to motion which is more pronounced in the central visual field than in some regions of the more peripheral field. Although both motion and differential luminance sensitivity decrease with age, the rate and the magnitude of the loss differ for these two visual functions.
With increasing pressure placed on natural systems by growing human populations, both scientists and resource managers need a better understanding of the relationships between cumulative stress from ...human activities and valued ecosystem services. Societies often seek to mitigate threats to these services through large-scale, costly restoration projects, such as the over one billion dollar Great Lakes Restoration Initiative currently underway. To help inform these efforts, we merged high-resolution spatial analyses of environmental stressors with mapping of ecosystem services for all five Great Lakes. Cumulative ecosystem stress is highest in near-shore habitats, but also extends offshore in Lakes Erie, Ontario, and Michigan. Variation in cumulative stress is driven largely by spatial concordance among multiple stressors, indicating the importance of considering all stressors when planning restoration activities. In addition, highly stressed areas reflect numerous different combinations of stressors rather than a single suite of problems, suggesting that a detailed understanding of the stressors needing alleviation could improve restoration planning. We also find that many important areas for fisheries and recreation are subject to high stress, indicating that ecosystem degradation could be threatening key services. Current restoration efforts have targeted high-stress sites almost exclusively, but generally without knowledge of the full range of stressors affecting these locations or differences among sites in service provisioning. Our results demonstrate that joint spatial analysis of stressors and ecosystem services can provide a critical foundation for maximizing social and ecological benefits from restoration investments.
Three hundred sixty-two adult patients were administered the Diagnostic Interview for Anxiety, Mood, and OCD and Related Neuropsychiatric Disorders (DIAMOND). Of these, 121 provided interrater ...reliability data, and 115 provided test–retest reliability data. Participants also completed a battery of self-report measures that assess symptoms of anxiety, mood, and obsessive-compulsive and related disorders. Interrater reliability of DIAMOND anxiety, mood, and obsessive-compulsive and related diagnoses ranged from very good to excellent. Test–retest reliability of DIAMOND diagnoses ranged from good to excellent. Convergent validity was established by significant between-group comparisons on applicable self-report measures for nearly all diagnoses. The results of the present study indicate that the DIAMOND is a promising semistructured diagnostic interview for DSM-5 disorders.
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