ERP-based Study on the Influence of Cognitive Load on Time-on-task Effect
The aim of this work is to study the influence of time-on-task effects on event related potential characteristics under different cognitive loads and explore the impact of mental workload on time-on-task effects.A cognitive function experimental paradigm based on the N-back task was designed.Twenty healthy subjects were recruited to participate in the experiment adopting this paradigm.Throughout the experiment,the subjective scale results and EEG signals of the subjects were collected for behavioral statistical analysis and event related potential analysis.With the enhancement of time on task,the reaction time(RT)of the subjects was significantly decreased when accomplishing the 3-back task,coefficient of variation of reaction time was increased both in 0-back task and 3-back task.During the N-back experiment,N1 amplitude increased significantly in occipital regions,while P300 amplitude in the prefrontal and central frontal regions decreased significantly.In both the 0-back and 3-back tasks,changes in P2 amplitude in subjects'prefrontal regions were linearly correlated with reaction time(r=-0.44,P＜0.05;r=-0.59,P＜0.05),while P2 amplitude was negatively correlated with the coefficient of variation of reaction time(r=-0.39,P＜0.05;r=-0.42,P＜0.05).In the 3-back task,the mean P300 amplitude in frontal,central and parietal regions was significantly correlated with reaction time(r=-0.49,P＜0.05),whereas the P300 amplitude in the 0-back task was significantly negatively correlated with reaction time and the coefficient of variation of reaction time(r=-0.69,P＜0.05;r=-0.51,P＜0.05).These results suggested that P2 and P300 in prefrontal and midfrontal regions were influenced by time-on-task effect,while the P300 of occipital region was more likely to be affected by cognitive load and time-on-task effect.
time-on-task effectelectroencephalography(EEG)event related potentialcognitive load
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