Abstract
Event-related brain potentials (ERPs) and reaction times (RTs) were recorded from 10 participants who switched tasks on successive trials and repeated the previous task. The tasks consisted of attending to a target letter and deciding if it was a vowel or a consonant in one task, and upper or lower case letter in the other. Task switching prolonged RTs compared to repeating the task when the cue preceding the target letter was not an effective predictor of the task, whereas an informative cue extinguished the switching effect. Cue-related ERPs revealed a positive modulation over posterior electrodes for information in a task-switching trial. Irrespective of task-switching or task-repeating trials, informative cues were associated with a relatively early negative modulation of target letter ERPs overlapping the temporal/occipital N160. In the later latency period, consistent and persistent task-switching effects were observed on target ERPs in non-informative cue trials. These findings indicate advance reconfiguration of task processing systems before the presentation of the task stimulus, and also suggest that the switching operation of distinct processes depends on task requirements. ( Japanese Journal of Physiological Psychology and Psychophysiology, 24 (3) : 237-247, 2006.)
