This study deals with the effect of stimulus contrast, between 1.3% and 96%, on the visual evoked potentials (VEPs) for onset of motion and for pattern reversal of checkerboard stimuli. The VEPs for pattern reversal and for the onset of motion both contain an initial positive peak (P1; peak latency about 120 msec) followed by a later negative peak (N2; peak latency 160-200 msec). However the P1...

Although there is a great deal of knowledge regarding the phylo- and ontogenetic plasticity of the neocortex, the precise nature of environmental impact on the newborn human brain is still one of the most controversial issues of neuroscience. The leading model-system of experience-dependent brain development is binocular vision, also called stereopsis. Here, we show that extra postnatal visual ...

Background Nutritional visual defects are apparently uncommon nowadays in developed nations. Retinal change-related caused by hypovitaminoses may be underdiagnosed. Aim of the study To investigate retinal structural and functional changes a patient with multivitamin deficiency before during vitamin supplementation. Methods A 51-year-old female had been on vegetarian diet as child, restrict vega...

Abstract Purpose Visual outcomes after cataract surgery in diabetic patients with retinal or visual pathway disease are difficult to predict as the fundus may be obscured, and assessment of potential is challenging. This study assessed value electrophysiology a prognostic indicator recovery cataract, prior surgery. Methods Forty-one (aged 52–80; 74 eyes) 13 age-matched non-diabetic control (21 ...

PURPOSE There is evidence that multifocal visual evoked potentials (VEPs) can be used as an objective tool to detect visual field loss. The aim of this study was to correlate multifocal VEP amplitudes with standard perimetry data and retinal nerve fibre layer (RNFL) thickness. METHOD Multifocal VEP recordings were performed with a four-channel electrode array using 58 stimulus fields (pattern...

Single visual evoked potentials (VEP) are very weak and noisy signals. For this reason, powerful extraction tools are needed to improve their clinical use. In this paper, we present two methods for filtering VEP: a linear one, based on the adaptive noise canceller scheme where the input signals represent successive recorded VEP, and a new non-linear method which exploits the neural network prop...

In this paper, Principal Component Analysis (PCA) is used to reduce noise from multi-channel Visual Evoked Potential (VEP) signals. PCA is applied to reduce noise from multi-channel VEP signals because VEP signals are more correlated from one channel to another as compared to noise during visual perception. Emulated VEP signals contaminated with noise are used to show the noise reduction abilit...

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...

BACKGROUND Visual cross-modal re-organization is a neurophysiological process that occurs in deafness. The intact sensory modality of vision recruits cortical areas from the deprived sensory modality of audition. Such compensatory plasticity is documented in deaf adults and animals, and is related to deficits in speech perception performance in cochlear-implanted adults. However, it is unclear ...

PURPOSE To evaluate macular function and neural conduction along postretinal visual pathways in amblyopic patients. METHODS Twenty-five anisometropic amblyopic patients (mean age, 7 ± 1.9 years; visual acuity [VA]: 0.44 ± 0.27 logMAR in amblyopic [AM] eyes and 0.023 ± 0.067 logMAR in sound [SE] eyes) and 25 age-similar control subject ([CE] eyes, VA of 0.0 ± 0.0 logMAR in both eyes) were enro...