Age-related differences in early novelty processing: Using PCA to parse the overlapping anterior P2 and N2 components

• PCA was used to examine age-related changes in early ERP processing of novelty.
• Is the inverse relationship between anterior P2 and N2 due to temporospatial overlap?
• Early and late P2, sensitive to relevance and novelty respectively, increase with age.
• N2 responsive to novelty decreases with age and inversely correlates with the late P2.
• Age-related differences in the P2 and N2 reflect changes in independent operations.

Previous work demonstrated age-associated increases in the anterior P2 and age-related decreases in the anterior N2 in response to novel stimuli. Principal component analysis (PCA) was used to determine if the inverse relationship between these components was due to their temporal and spatial overlap. PCA revealed an early anterior P2, sensitive to task relevance, and a late anterior P2, responsive to novelty, both exhibiting age-related amplitude increases. A PCA factor representing the anterior N2, sensitive to novelty, exhibited age-related amplitude decreases. The late P2 and N2 to novels inversely correlated. Larger late P2 amplitude to novels was associated with better behavioral performance. Age-related differences in the anterior P2 and N2 to novel stimuli likely represent age-associated changes in independent cognitive operations. Enhanced anterior P2 activity (indexing augmentation in motivational salience) may be a compensatory mechanism for diminished anterior N2 activity (indexing reduced ability of older adults to process ambiguous representations).