The effect of spatial contrast on response gain of the human visual system will be studied using corneal (ERG) and scalp (VEP) recordings and by evaluating related psychophysical functions. First, """"""""transient"""""""" and """"""""steady state"""""""" ERG components which can be attributed to spatial contrast and not simply to rectified local luminance responses will be identified. Sequential processing stages and areal interactions of the human retina will be evaluated from amplitude and phase properties of linear and nonlinear (interactive) steady-state response components which occur when two temporal frequencies of modulation are simultaneously applied to a grating pattern. The effect of surround and overlap contrast masking on both luminance and pattern responses will be studied electrophysiologically and psychophysically. Our studies will answer whether or not there is a retinal mechanism of surround masking. If present, differences in surround and overlap masking may be advantageously used to contrast retinal and cortical networks, as it has been suggested some time ago that different types of masking may occur at different levels of the visual system. We will answer the question of whether or not a spatial, as separate from temporal, nonlinearity precedes the surround """"""""masking"""""""" stage. At the moment, the effect of spatial nonlinearities on masking is unknown either from psychophysical or VEP studies. Understanding the gain control of contrast on retinal responses is relevant to patients who suffer from Parkinson's disease (PD). Previous studies suggest impaired modulatory effect of dopamine (DA) on contrast responses in different species, including man. The proposed studies will evaluate if DA in the human affects contrast gain via an intraretinal feedback loop. These studies will reveal new pathophysiological concepts of PD. Analyzing interactive frequency responses, we wish to discern the effect of partial or complete scotoma on areal interactions. These may be defective in early glaucoma, perhaps prior to manifest visual field changes. Our previous studies suggest impaired low spatial frequency responses in glaucoma, while animal studies demonstrate abnormal magnocellular functions in this disease. The present studies will describe nonlinear visual responses in glaucoma and ocular hypertension (OHT). These studies may help to identify visual changes in OHT without visual field defects and thus contribute to a better understanding of the pathophysiology and early diagnosis and treatment of glaucoma.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY001708-11
Application #
3256145
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1977-02-01
Project End
1990-02-28
Budget Start
1987-03-01
Budget End
1988-02-29
Support Year
11
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Mount Sinai School of Medicine
Department
Type
Schools of Medicine
DUNS #
City
New York
State
NY
Country
United States
Zip Code
10029
Bodis-Wollner, Ivan; Brannan, Julie R; Storch, Rita L et al. (2009) The effect of background spatial contrast on electroretinographic responses in the human retina. Vision Res 49:922-30
Bodis-Wollner, I; Borod, J C; Cicero, B et al. (1995) Modality dependent changes in event-related potentials correlate with specific cognitive functions in nondemented patients with Parkinson's disease. J Neural Transm Park Dis Dement Sect 9:197-209
Antal, A; Kovanecz, I; Bodis-Wollner, I (1994) Visual discrimination and P300 are affected in parallel by cholinergic agents in the behaving monkey. Physiol Behav 56:161-6
Antal, A; Bodis-Wollner, I; Ghilardi, M F et al. (1993) The effect of levo-acetyl-carnitine on visual cognitive evoked potentials in the behaving monkey. Electroencephalogr Clin Neurophysiol 86:268-74
Brannan, J R; Bodis-Wollner, I; Storch, R L (1992) Evidence for two distinct nonlinear components in the human pattern ERG. Vision Res 32:11-7
Glover, A; Ghilardi, M F; Bodis-Wollner, I et al. (1991) Visual 'cognitive' evoked potentials in the behaving monkey. Electroencephalogr Clin Neurophysiol 80:65-72
Bodis-Wollner, I; Chung, E; Ghilardi, M F et al. (1991) Acetyl-levo-carnitine protects against MPTP-induced parkinsonism in primates. J Neural Transm Park Dis Dement Sect 3:63-72
Bodis-Wollner, I (1990) The visual system in Parkinson's disease. Res Publ Assoc Res Nerv Ment Dis 67:297-316
Pang, S; Borod, J C; Hernandez, A et al. (1990) The auditory P 300 correlates with specific cognitive deficits in Parkinson's disease. J Neural Transm Park Dis Dement Sect 2:249-64
Bodis-Wollner, I (1990) Visual deficits related to dopamine deficiency in experimental animals and Parkinson's disease patients. Trends Neurosci 13:296-302

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