ABSTRACT
Objective To investigate the neural processing of stimulus salience and behavioral relevance with spatiotemporal patterns of event-related potentials (ERP).Methods The ERP was recorded from 20 subjects while they performed Eriksen task.Each stimulus picture contained 3 symbols:a central target (grey symbol ＜/ ＞ or X) represented pressing the corresponding button or withdrawing response respectively.And the flanking distractors were classified by both behavioral relevance ( ＜/ ＞-facilitory,X-inhibitory,H-irrelevant) and color salience (red,grey).Results Significant interaction effect was found for the reaction time(F(1.85,3521)=13.015,P＜0.001).Significant difference was found between the salient ((411.91 ±40.39) ms) and the non-salient ((420.42±38.58) ms) under the facilitory condition(t (19) =-4.858,P＜0.001).The significant ERP effects were revealed by statistical parametric mapping of F-value.The saliency effects appeared in the right occipital-temporal regions (100-125 ms),the bilateral dorsal attentional network (DAN) (150-300 ms) and the right-lateralized ventral attentional network (VAN) (300-450 ms).The effects of the behavioral relevance occurred in the occipital regions (150-200 ms),the VAN (200-300 ms) and the DAN (300-600 ms).The interaction effects of behavioral relevance between the target and the distractor occurred in the DAN (200-350 ms).Conclusion The information of the distractor salience and behavioral relevance access VAN and DAN in different stages respectively.The ERP effect in the DAN may be the neural correlation of contingent attentional capture.
ABSTRACT
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 ～900ms).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.