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      A practical method of measuring the human 
temporal contrast sensitivity function

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          Abstract

          One of the more significant indicators of neural age-related loss and disease is reduced temporal processing speed. It would, therefore, be useful to have an accurate and practical device that measures the full range of an individual's temporal processing abilities (characterized as the temporal contrast sensitivity function, TCSF). 70 subjects (15-84 yrs) were tested. A small tabletop device utilizing electronic control of light-emitting diodes (LEDs) was constructed that delivered a 1-degree, 660 nm test (the modulation depth of which could be adjusted directly by the subject) centered within a 10-degree 660 nm surround. The method provided a TCSF that had a shape consistent with past studies (peaking around 8 Hz). Also consistent with past work, the largest age-decline was found at the highest frequencies and for the central fovea ( r = 0.47, p<0.0001, ~2 Hz per decade). Psychophysical assessment of temporal vision offers an easy and dynamic measure of central visual function.

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          Most cited references26

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          Factors affecting light-adapted pupil size in normal human subjects.

          To investigate the effect of age, gender, refractive error, and iris color on light-adapted pupil size in humans. Pupil diameters of 91 subjects (age range, 17 to 83 years) with normal, healthy eyes were measured using an objective infrared-based continuous recording technique. Five photopic ocular illuminance levels were used (2.15 to 1050 lumens m-2), and the accommodative status of each subject was precisely controlled at a constant level. Pupil size decreased linearly as a function of age at all illuminance levels. Even at the highest illuminance level, there was still a significant effect of age upon pupil size. The rate of change of pupil diameter with age decreased from 0.043 mm per year at the lowest illuminance level to 0.015 mm per year at the highest. In addition, the variability between pupil sizes of subjects of the same age decreased by a factor of approximately two as luminance was increased over the range investigated. Pupil size was found to be independent of gender, refractive error, or iris color (P > 0.1). Of the factors investigated, only chronologic age had a significant effect on the size of the pupil. The phenomenon of senile miosis is present over a wide range of ocular illuminance levels.
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            Reversals of age-related declines in neuronal signal transduction, cognitive, and motor behavioral deficits with blueberry, spinach, or strawberry dietary supplementation.

            Ample research indicates that age-related neuronal-behavioral decrements are the result of oxidative stress that may be ameliorated by antioxidants. Our previous study had shown that rats given dietary supplements of fruit and vegetable extracts with high antioxidant activity for 8 months beginning at 6 months of age retarded age-related declines in neuronal and cognitive function. The present study showed that such supplements (strawberry, spinach, or blueberry at 14.8, 9.1, or 18.6 gm of dried aqueous extract per kilogram of diet, respectively) fed for 8 weeks to 19-month-old Fischer 344 rats were also effective in reversing age-related deficits in several neuronal and behavioral parameters including: oxotremorine enhancement of K(+)-evoked release of dopamine from striatal slices, carbachol-stimulated GTPase activity, striatal Ca(45) buffering in striatal synaptosomes, motor behavioral performance on the rod walking and accelerod tasks, and Morris water maze performance. These findings suggest that, in addition to their known beneficial effects on cancer and heart disease, phytochemicals present in antioxidant-rich foods may be beneficial in reversing the course of neuronal and behavioral aging.
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              Visual response to time-dependent stimuli. I. Amplitude sensitivity measurements.

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                Author and article information

                Journal
                Biomed Opt Express
                BOE
                Biomedical Optics Express
                Optical Society of America
                2156-7085
                02 August 2010
                14 July 2010
                14 July 2010
                : 1
                : 1
                : 47-58
                Affiliations
                [1 ]Walter S. Hunter Laboratory, Department of Psychology, Brown University, 
89 Waterman Street, Providence, RI 02912, USA
                [2 ]Vision Science Laboratory, Department of Psychology, University of Georgia, Athens, GA 30602, USA
                Author notes
                Article
                127550
                10.1364/BOE.1.000047
                3005172
                21258445
                9825654a-f0bb-49a0-955a-2da95ab7947a
                ©2010 Optical Society of America

                This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Unported License, which permits download and redistribution, provided that the original work is properly cited. This license restricts the article from being modified or used commercially.

                History
                : 26 April 2010
                : 22 June 2010
                : 25 June 2010
                Funding
                Funded by: Cognis Gmbh
                Categories
                Neuroscience and Brain Imaging
                Custom metadata
                True
                12

                Vision sciences
                (230.0230) optical devices,(107.0170) medical optics and biotechnology,(220.0220) optical design and fabrication,(120.0120) instrumentation, measurement and metrology,(330.0330) vision, color and visual optics

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