Personality Traits Modulate the Impact of Emotional Stimuli During a Working Memory Task: A Near-Infrared Spectroscopy Study

• Published in: Frontiers in behavioral neuroscience Vol. 14; p. 514414
• Main Authors: Sugi, Masaaki, Sakuraba, Satoshi, Saito, Hirotada, Miyazaki, Mitsunori, Yoshida, Susumu, Kamada, Tatsuhiro, Sakai, Shinya, Sawamura, Daisuke
• Format: Journal Article
• Language: English
• Published: Lausanne Frontiers Research Foundation 17-09-2020; Frontiers Media S.A
• Subjects: Behavioral Neuroscience; Brain research; dorsolateral prefrontal cortex; dual n-back task; emotional stimuli; Emotions; Handedness; Hemoglobin; I.R. radiation; Infrared spectroscopy; Memory; Mental task performance; near-infrared spectroscopy; Neuroimaging; Personality; personality trait; Personality traits; Prefrontal cortex; Reaction time task; Short term memory; Spectrum analysis; Variance analysis
• ISSN: 1662-5153; 1662-5153
• DOI: 10.3389/fnbeh.2020.514414

The purpose of the present study was to examine the influence of personality traits on the impact of emotional stimuli focusing on n-back task performance and brain activity changes. Previous neuroimaging studies have reported that individual differences in emotional processing can be attributed to personality traits, which is linked to the hemisphere-specific activity of the dorsolateral prefrontal cortex (DLPFC) in response to emotional stimuli. Thirty right-handed healthy young male participants were recruited in this study and classified into two groups, the behavioral inhibition system (BIS) group and behavioral activation system (BAS) group, based on their scores on the BIS/BAS scale. Participants saw six emotional images (two each with negative, neutral, and positive valence), which were selected from the International Affective Picture System and validated in a preliminary experiment. Then, a dual 2-back task that simultaneously employed auditory-verbal and visuospatial stimuli was conducted. Additionally, the concentration of oxygenated hemoglobin (Oxy-Hb) changes in the DLPFC were measured during the image presentation and dual 2-back task by near-infrared spectroscopy. The task performance showed a significantly increased reaction time in the negative valence independent of personality traits. The results of Oxy-Hb changes showed a significant interaction between personality traits and emotional valence. Further hemisphere-subgroup analysis revealed that the right DLPFC activity was significantly higher in the negative valence than in the neutral valence in the BIS group; right DLPFC activity was also significantly higher in the BIS group than in BAS group in the positive valence. There was no main effect or interaction in the left DLPFC activity. These findings suggest the importance of considering personality traits when examining the impact of emotional stimuli. Further studies with large sample sizes warranted to examine the influence emotional stimuli exert on working memory performance, considering the personality traits to better understand individual differences in emotional processing.