Age-related differences in neural activity and functional connectivity during self- and other-referential processing: An EEG study.

Research on brain aging has largely focused on neurological disorders such as Alzheimer's disease, mild cognitive impairment, and other forms of cognitive decline. However, relatively few studies have examined how age affects self-knowledge in healthy older adults. Thus, the present study aimed to investigate the impact of age on the neural correlates of self-referential and other-referential processing, as well as patterns of task-related connectivity. To this end, trait adjectives were presented to younger and older adults, who evaluated their suitability for describing the self, a close other, and a famous person while EEG data were recorded. EEG analyses focused on the early attention-related positivity (P1) and the late positive potential (LPP), reflecting enhanced processing of salient stimuli, as well as task-related functional connectivity assessed using the full-frequency directed transfer function. Compared to younger adults, older participants exhibited lower P1 amplitudes, indicating reduced attentional engagement. In the older group, LPP amplitudes associated with self-related personality traits were higher than in the younger group. This enhanced LPP may suggest stronger emotional responses to self-related traits and/or increased cognitive effort during self-evaluation. Overall, directed connectivity analyses revealed reduced information flow in older adults along both bottom-up and top-down pathways, including feed-forward signaling from perceptual regions to higher-order evaluative systems, as well as feedback signaling from internally oriented networks to sensory regions. Age-related differences were also evident in local connectivity patterns, with younger participants exhibiting stronger within-region connectivity than older participants in perceptual processing regions and regions supporting internally oriented cognitive processes.