To determine the manner in which attention is distributed among numerous locations in the visual space, we used a multifocal recording technique that allowed simultaneous recordings of evoked cortical activity from 12 visual field areas out to 23.6 degrees. We found that multifocal visual evoked potential (mfVEP) amplitude was larger when a region of visual space was attended than when it was n...

Seven out of 12 normal subjects could deliberately produce abnormal pattern-reversal visual evoked potentials (VEPs) which simulated disorders of the anterior visual pathways without detection. In six the mechanism was near-point accommodation and in one eccentric fixation. If voluntary suppression of the VEPs is suspected various modifications to the recording technique may be of value. These ...

This study investigated the effect of attention on the contrast response curves of steady-state visual evoked potentials (VEPs) to counter-phased sinusoidal gratings. The 1 cyc/deg gratings were modulated either in luminance or chromaticity (equiluminant red-green). The luminance grating counter-phased at 9 Hz (to favour activation of the magno-cellular system), and the chromatic grating at 2.5...

The objective of this study is development of driver’s sleepiness using Visually Evoked Potentials (VEP). VEP computed from EEG signals from the visual cortex. We use the Steady State VEPs (SSVEPs) that are one of the most important EEG signals used in human computer interface systems. SSVEP is a response to visual stimuli presented. We present a classification method to discriminate between...