Место издания:Blackwell Publishing Inc United Kingdom
Первая страница:S88
Аннотация:Nowadays eye movements (EM) are usually recorded by the video eye tracking (ET)
technology. It is widely used for EM pattern analyses during complex image scanning
but usually not with simultaneous EEG recording. EEG dynamics is traditionally
considered to indicate processes related to visual task performance. By EEG and ET
synchronization we marked out the short EEG epochs concurrent with the moment of
finding the RS and analyzed ERD dynamics.We studied the alpha band ERD induced
by finding a nonverbal relevant stimulus (RS) among about fifty nonverbal irrelevant
ones in a visual search task paradigm. Subjects were instructed to find the RS and
fixate gaze on it for a couple of seconds. After each test trial the subjects were asked to
fixate on the four RS that were exposed and angular points of rectangle (control
session). The gaze fixation on RS was verified by ET. The finding of RS in test trials
induced the ERD 2 – 2.5 times greater and longer than in control trials for all leads.
ERD was better exposed in frontal leads in test trials, and in occipital leads in control
trials. We suppose that mostly bottom-up attentional processes were involved in control
task, as occipital ERD was expressed better. The visual search task performance
additionally involves the top-down attentional process that is proved by better expressed
ERD in all leads, especially in frontal leads. We suppose that ERD features
and spatial distribution to indicate the different attentional processes’ contributions to
different task performances.