Manual reaction time (RT) and visual evoked potentials (VEP) were measured in motion onset and offset detection tasks. A considerable homology was observed between the temporal structure of RTs and VEP intervals, provided that the change in motion was detected as soon as the VEP signal has reached critical threshold amplitude. Both manual reactions and VEP rise in latency as the velocity of the...

This paper presents the author’s scientific hypothesis on the effect of fractal flickering, which exhibits scale invariance with time, on the evoked responses of the retina [electroretinogram (ERG)] and visual cortex [visual-evoked cortical potentials (VEP)] in norm and neurodegenerative disorders. A new approach for ERG and VEP studies is proposed. In the proposed approach, standard stimuli ar...

A simulation and experimental study has been conducted on equivalent dipole layer imaging (EDLI) of brain electric sources from EEG. Using the three-sphere inhomogeneous head model, the performance of the EDLI was rigorously evaluated for a variety of brain source configurations under different noise levels. The present simulation results demonstrate the excellent performance of the EDLI in map...

Visual perception is mediated by unique contributions of the numerous brain regions that constitute the visual system. We performed simultaneous recordings of local field potentials (LFPs) and single unit activity (SUA) in areas V4 and lateral prefrontal cortex to characterize their contribution to visual processing. Here, we trained monkeys to identify natural images at different degradation l...

BACKGROUND The mechanisms underlying the interictal habituation deficit of cortical visual evoked potentials (VEP) in migraine are not well understood. Abnormal long-term functional plasticity of the visual cortex may play a role and it can be assessed experimentally by light deprivation (LD). METHODS We have compared the effects of LD on VEP in migraine patients without aura between attacks ...

introduction: demyelination is one of the main causes of neurological disability. it is the end product of numerous pathological processes, multiple sclerosis (ms) being the most common cause. more than 70% of the ms patients suffer from optic disturbances. this disease commonly affects the optic pathway, particularly the optic nerves and chiasm. several attempts have been made to produce a sui...

BACKGROUND To compare the usefulness of the traditional pattern-reversal Visual Evoked Potentials (VEP) with multifocal VEP (mfVEP) and Frequency-Doubling Technology (FDT) perimetry in the evaluation of the ocular abnormalities induced by acute or subacute optic neuritis (ON). MATERIALS AND METHODS The test results of 24 ON patients were compared with those obtained in 40 normal control subje...

PURPOSE To compare the Cambridge contrast sensitivity (CS) test and visual evoked potentials (VEP) in detecting visual impairment in a population of visually symptomatic and asymptomatic patients affected by clinically definite multiple sclerosis (MS). METHODS Fifty patients (100 eyes) presenting with MS and 25 healthy subjects (50 eyes) with normal corrected visual acuity were included in th...

BACKGROUND The purpose of this study was to determine the predictive value of flash visual-evoked potentials (VEP), relative afferent pupillary defect, and presence of orbital fractures in patients with traumatic optic neuropathy. METHODS A prospective study was conducted in 15 patients with indirect traumatic optic neuropathy. All patients underwent a thorough ophthalmic examination. Initial...

Visual evoked potentials (VEP) were measured in 36 patients with early-treated phenylketonuria (PKU; aged 1 to 11 years) and good metabolic control before and after supplementation with omega-3 long-chain polyunsaturated fatty acids (LC-PUFA) from fish oil. Patients with PKU had significantly longer P100 latencies than 22 age-matched control subjects. After 3 months of LC-PUFA supplementation, ...