ERP INDICATIONS FOR SUSTAINED AND TRANSIENT AUDITORY SPATIAL ATTENTION WITH DIFFERENT LATERALIZATION CUES

The presented study was designed to investigate ERP effects of auditory spatial attention in sustained attention condition (where the to-be-attended location is defined in a blockwise manner) and in a transient attention condition (where the to-be-attended location is defined in a trial-by-trial manner). Lateralization in the azimuth plane was manipulated (a) via monaural presentation of left- and right-ear sounds, (b) via interaural intensity differences, (c) via interaural time differences, (d) via an artificial-head recording, and (e) via free-field stimulation. Ten participants were delivered with frequent Nogo- and infrequent Go-Stimuli. In one half of the experiment participants were instructed to press a button if they detected a Go-stimulus at a predefined side (sustained attention), in the other half they were required to detect Go-stimuli following an arrow-cue at the cued side (transient attention). Results revealed negative differences (Nd) between ERPs elicited by to-be-attended and to-be-ignored sounds in all conditions. These Nd-effects were larger for the sustained than for the transient attention condition indicating that attentional selection according to spatial criteria is improved when subjects can focus to one and the same location for a series of stimuli.