The long term aim is to combine basic and applied research so as of modern psychophysical and neurophysiological vision research to advancing our knowledge of human eye and brain disorders, to improving diagnostic and monitoring procedures, and to improving tests for comparing experimental therapies. To achieve our short term aims we will further develop our motion-defined letter reading test for detecting visual loss hidden to Snellen acuity and contrast sensitivity tests and, by comparing motion- defined letter test results with the results of other visual tests in patients with known brain lesions, we will establish the specificity of the test. Our short term aims are as follows: (1) Find whether focal lesions in parietal cortex can produce selective loss of the ability to detect and/or read motion-defined letters while sparing sensitivity to local or to global motion, color vision, fine depth perception, and the ability to read contrast-defined letters of high and low contrast (i.e. visual acuity for high- and low- contrast letters). Find whether focal lesions in temporal cortex produce patterns of loss in which the ability to detect and read motion-defined letters is spared. (2) Find whether multiple sclerosis can cause the patterns of loss described in (1). (3) By investigating the effects of dot lifetime and stimulus presentation duration, determine the extent to which the losses of ability to detect and/or read motion-defined letters in (1) and (2) are a consequence of abnormal dynamics of motion processing.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY007569-06
Application #
3264591
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1988-06-01
Project End
1994-09-29
Budget Start
1993-09-30
Budget End
1994-09-29
Support Year
6
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Toronto
Department
Type
DUNS #
259999779
City
Toronto
State
ON
Country
Canada
Zip Code
M5 1-S8
Giaschi, D; Lang, A; Regan, D (1997) Reversible dissociation of sensitivity to dynamic stimuli in Parkinson's disease: is magnocellular function essential to reading motion-defined letters? Vision Res 37:3531-4
Giaschi, D; Regan, D (1997) Development of motion-defined figure-ground segregation in preschool and older children, using a letter-identification task. Optom Vis Sci 74:761-7
Giaschi, D E; Trope, G E; Kothe, A C et al. (1996) Loss of sensitivity to motion-defined form in patients with primary open-angle glaucoma and ocular hypertension. J Opt Soc Am A Opt Image Sci Vis 13:707-15
Regan, D; He, P (1995) Magnetic and electrical responses of the human brain to texture-defined form and to textons. J Neurophysiol 74:1167-78
Regan, D; Simpson, T (1995) Multiple sclerosis can cause visual processing deficits specific to texture-defined form. Neurology 45:809-15
Giaschi, D E; Regan, D; Kraft, S P et al. (1993) Crowding and contrast in amblyopia. Optom Vis Sci 70:192-7
Giaschi, D E; Regan, D; Kraft, S P et al. (1992) Defective processing of motion-defined form in the fellow eye of patients with unilateral amblyopia. Invest Ophthalmol Vis Sci 33:2483-9
Giaschi, D; Regan, D; Kothe, A et al. (1992) Motion-defined letter detection and recognition in patients with multiple sclerosis. Ann Neurol 31:621-8
Regan, D; Giaschi, D; Sharpe, J A et al. (1992) Visual processing of motion-defined form: selective failure in patients with parietotemporal lesions. J Neurosci 12:2198-210
Regan, D; Giaschi, D E; Kraft, S P et al. (1992) Method for identifying amblyopes whose reduced line acuity is caused by defective selection and/or control of gaze. Ophthalmic Physiol Opt 12:425-32

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