O175 High-density ERPS for working memory for faces, words, and figures in young and elder healthy volunteers

Abstract

Objectives We aimed at studying brain electrical activity underlying the changes in working memory encoding for different kinds of visual stimuli, related to healthy aging. Methods The participants were young healthy adults (10 female and 12 male), aged 20–30 years and elder healthy adults (12 female and 12 male), aged 50–70 years. All participants performed three delayed match-to-sample visual tasks. The stimuli were monochrome photographs of unfamiliar faces, patterns composed of 8 cubes, and 5-letter Russian abstract nouns. Participants had to memorize the first stimulus in a pair and compare it to the second stimulus presented with 2000 ms delay. 128-channel EEG was recorded with 500 Hz digitization rate. We analyzed the visual response elicited by the first stimulus in a pair and the following slow potential (CNV). Results The task-specific age-related differences ( p 0.05 ) were found in N170 component. Its amplitude was reduced for geometric patterns, and enhanced for faces and words in Elder compared to Young group. The differences were task-specific in their topography in 450–900 ms time window (LPP) and in early CNV. The non-specific age-related amplitude reduction ( p 0.05 ) in elders was in P100 and P300 components, and the non-specific amplitude increase was in N280 and CNV in the central region. Discussion Brain activity during visual item encoding and maintenance showed task-specific and non-specific differences between elder and young healthy participants, depending on the latency of the recorded components of evoked activity. Conclusions The non-specific increased electrical brain activity recorded from the scalp surface in Elder group can be a manifestation of general compensatory processes taking place in the certain brain structures in healthy aging. Significance The results may have a prognostic value for healthy aging vs. age-related memory problems.