Short presentation for task cue reducing switch cost: a spatiotemporal analysis of ERP

Objective To investigate the neural mechanism of the reduction of switch cost induced by short presentation of the task cue. Methods The event-related potentials(ERP) was recorded from 19 subjects while they performed a Chinese Stroop switching task.The factorial design of repeated-measures was adopted with the cue presentation time (100/1000 ms) and the type of succeeding task (repeat/switch). Results For the switch cost of reaction time (the switch subtracts the repeat), the difference between the long cue group (15.0±33.3 ms) and the short group (0.80±40.7 ms) had the significantly tendency(t(18)=-1.77, P=0.09). During the stage of cue processing, the ERP effects of cue reveal in the frontal-occipital areas (100~200 ms), frontoparietal and tempo-occipital regions (200~500 ms), frontoparietal network and centro-occipital regions (500~900 ms). During the stage of task execution, the ERP effects of the cue were observed from the left fronto-occipital areas (300~400 ms) to parieto-occipital areas (400~900 ms). The ERP effects of the task started from the right hemisphere (500~600 ms) and extended to bilateral prefrontal and centro-parietal area (600~900 ms). Conclusion The short cue presentation can not only start up the preparation of frontoparietal network earlier during cue processing stage but also enhance its retrieval in the left dorsal lateral frontal cortex during task executive stage. Key words: Switching Stroop task; Switch cost; Event-related potentials