Human Steady-State Visual and Auditory Evoked Potential Components During a Selective Discrimination Task

Abstract

Human steady-state visual and auditory evoked potentials were measured in 10 Ss (aged 17–30 yrs) during a sequence of visual and auditory discrimination tasks requiring attention, and the detection of just-noticeable differences in stimulus intensity. Both stimuli were always present, and visual and auditory evoked potentials were measured simultaneously. Evoked potentials were measured by synchronous filtering of the EEG at the stimulus fundamental and its first harmonic. The experiment alternated visual and auditory discrimination tasks in a manner designed to demonstrate the effects of attention shifts, separate from changes in general alertness or arousal. Confirming prior studies, auditory evoked potentials were found to be insensitive to directed attention shifts. However, visual evoked potential correlates of directed attention were found in some Ss. Considerable inter-S variability was found, suggesting differences in cognitive style or strategies during the task. This method appears to be useful in studying short-term effects in evoked potentials as a function of attention, alertness, and time effects. (PsycINFO Database Record (c) 2016 APA, all rights reserved)