Effect of blur level and stimulus type on N-Back task performance: An EEG study

Abstract

ABSTRACT While the impact of task difficulty level on working memory (WM) has been addressed using a visual N-Back task, only few studies considered the effect of stimulus blur level. We investigated the effect of N-Back difficultly level, blur level as well as stimulus type using, for the first time, electroencephalogram (EEG) responses. We recruited 18 healthy young individuals and recorded their behavioural and EEG responses when participating in a single N-Back session. Our results showed interactions between blur level and stimulus type. Frequency band differences were found for all three stimulus types (faces, objects and natural scenes) when comparing no blur, modest, and severe blur. Additionally, when comparing stimuli, we found differences in higher frequency bands for faces compared to objects and natural scenes, for all three N-Back levels. Only in the frontal areas, differences in higher frequency bands were identified in objects compared to faces and natural scenes. These results offer new insights into the neural dynamics underlying WM.