نتایج جستجو برای: visual evoked potentials

تعداد نتایج: 483133  

Journal: :Investigative ophthalmology & visual science 1987
S Sokol A Moskowitz V Hansen

Visually-evoked potentials (VEPs) were recorded from infants between the ages of 2 and 11 months in response to 2.5 c/deg main axis and oblique square wave gratings. The oblique effect first appears at 3 months of age; some infants showed smaller VEP amplitude and/or longer VEP latency for obliquely oriented gratings. Regarding the age of onset of the oblique effect, VEP data from this study ag...

Journal: :Vision research 1985
S B Steinman D M Levi S A Klein R E Manny

Hyperacuity thresholds of a few arc seconds can be achieved psychophysically for a variety of spatial localization tasks. The present experiments show that evoked potentials can be elicited in response to the introduction of vernier offsets, but not by the introduction of other cues to hyperacuity such as bisection or relative pattern motion, although each of these cues is equally salient psych...

Journal: :Journal of neurology, neurosurgery, and psychiatry 1982
J C Walsh R Garrick J Cameron J G McLeod

Visual, spinal and somatosensory evoked potentials were performed on 56 patients with clinically definite multiple sclerosis at the beginning and end of a 2 1/2 year follow-up period. At the initial examination one or both visual evoked potentials were abnormal in all but nine patients (84%), five of whom had abnormalities of either spinal or somatosensory evoked responses; that is, one or more...

Journal: :Journal of medical genetics 1988
D Castle J Kromberg R Kowalsky R Moosa N Gillman E Zwane V Fritz

Visual evoked potential testing was performed on 15 Negro carriers of the gene for tyrosinase positive oculocutaneous albinism in order to detect whether they have the same visual pathway decussation anomalies as do homozygotes. No subject showed 01-02 asymmetry on monocular testing, indicating that decussation follows the normal pattern. It is concluded that visual evoked potential testing is ...

Journal: :Journal of vision 2015
Anthony M Norcia L Gregory Appelbaum Justin M Ales Benoit R Cottereau Bruno Rossion

Periodic visual stimulation and analysis of the resulting steady-state visual evoked potentials were first introduced over 80 years ago as a means to study visual sensation and perception. From the first single-channel recording of responses to modulated light to the present use of sophisticated digital displays composed of complex visual stimuli and high-density recording arrays, steady-state ...

Journal: :Turkish journal of medical sciences 2015
Nihat Demir Ahmet Koç Mahmut Abuhandan Mustafa Calik Akin Işcan

BACKGROUND/AIM Vitamin B12 plays an important role in the development of mental, motor, cognitive, and social functions via its role in DNA synthesis and nerve myelination. Its deficiency in infants might cause neuromotor retardation as well as megaloblastic anemia. The objective of this study was to investigate the effects of infantile vitamin B12 deficiency on evoked brain potentials and dete...

Journal: :Investigative ophthalmology & visual science 1985
S J Bass J Sherman I Bodis-Wollner S Nath

Although a delayed visual evoked potential is considered to be the hallmark of optic nerve disease, relatively little has been published about VEP delays in macular disease. In this study, 20 patients with either acquired unilateral maculopathy or bilateral maculopathy in which one eye was more affected than the other were evaluated. VEP amplitudes and peak latencies were compared between eyes ...

Journal: :Electroencephalography and clinical neurophysiology 1985
S T Boysen G G Berntson

Visual evoked potentials (VEPs) in response to flash stimuli were recorded from occipital and central-scalp electrodes in the chimpanzee and gorilla. The most notable occipital component of the VEP was a surface-positive wave (P90), the latency of which decreased with development. Central scalp responses, apparent only in older animals, included a characteristic long-latency 'vertex wave' (N125...

Journal: :Vision Research 1999
Michael Hoffmann Thorsten J. Dorn Michael Bach

The aim of this study was to quantitatively describe the dynamics of adaptation to visual motion with electrophysiological and psychophysical methods in man. We recorded visual evoked potentials (VEPs) to motion onset of random dot patterns from occipital and occipito-temporal electrodes during a succession of adaptation-recovery sequences. In these sequences the test stimulus was used to set t...

Journal: :Investigative ophthalmology & visual science 1979
S Sokol D Nadler

Electroretinograms (ERGs) and visually evoked potentials (VEPs) were recorded simultaneously from each eye of three adult amblyopes. A spatially alternating checkerboard pattern stimulus of constant mean luminance was used to eliminate the effect of stray light on the ERG. The VEP was affected in the amblyopic eye of all subjects. In two subjects the VEP amplitude was reduced; in the third subj...

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