Disentangling periodic and aperiodic resting EEG correlates of personality

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2024-06, Vol.293, p.120628-120628, Article 120628
• Main Authors: Pacheco, Luiza Bonfim, Feuerriegel, Daniel, Jach, Hayley K., Robinson, Elizabeth, Duong, Vu Ngoc, Bode, Stefan, Smillie, Luke D.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Affect (Psychology); Alpha Rhythm - physiology; Aperiodic activity; Big five; Brain - physiology; Brain research; EEG; Electrodes; Electroencephalography - methods; Extraversion, Psychological; Female; Frontal asymmetry; Humans; Investigations; Machine Learning; Male; MVPA; Neurosciences; Personality; Personality - physiology; Personality traits; Research programs; Rest - physiology; Reward; Theta Rhythm - physiology; Young Adult
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2024.120628

•We explored resting EEG periodic and aperiodic activity and personality traits.•Extraversion didn't correlate with the periodic power of reward sensitivity indexes at rest.•Decoding of personality traits performed better for periodic power, compared to total power.•Agreeableness could be meaningfully decoded from aperiodic activity.•We discuss why periodic and aperiodic activity should be separated in personality research. Previous studies of resting electroencephalography (EEG) correlates of personality traits have conflated periodic and aperiodic sources of EEG signals. Because these are associated with different underlying neural dynamics, disentangling them can avoid measurement confounds and clarify findings. In a large sample (n = 300), we investigated how disentangling these activities impacts findings related to two research programs within personality neuroscience. In Study 1 we examined associations between Extraversion and two putative markers of reward sensitivity—Left Frontal Alpha asymmetry (LFA) and Frontal-Posterior Theta (FPT). In Study 2 we used machine learning to predict personality trait scores from resting EEG. In both studies, power within each EEG frequency bin was quantified as both total power and separate contributions of periodic and aperiodic activity. In Study 1, total power LFA and FPT correlated negatively with Extraversion (r ∼ -0.14), but there was no relation when LFA and FPT were derived only from periodic activity. In Study 2, all Big Five traits could be decoded from periodic power (r ∼ 0.20), and Agreeableness could also be decoded from total power and from aperiodic indices. Taken together, these results show how separation of periodic and aperiodic activity in resting EEG may clarify findings in personality neuroscience. Disentangling these signals allows for more reliable findings relating to periodic EEG markers of personality, and highlights novel aperiodic markers to be explored in future research.