Age-related effects on perceptual and semantic encoding in memory.

Area of Science:

• Cognitive Neuroscience
• Neuroscience
• Psychology

Background:

• The subsequent memory effect (SME) reflects neural activity differentiating subsequently remembered from forgotten items.
• Aging is associated with cognitive declines, including memory encoding, but the specific impact on different encoding types requires further investigation.

Purpose of the Study:

• To investigate age-related differences in the subsequent memory effect (SME) during perceptual and semantic encoding using event-related potentials (ERPs).
• To explore how aging affects the neural correlates of memory encoding, particularly in frontal regions.

Main Methods:

• Seventeen younger and 17 older adults performed perceptual and semantic encoding tasks with Chinese characters.
• Event-related potentials (ERPs) were recorded during encoding and recognition phases.
• Analysis focused on SMEs across different ERP components (P2, N3, P550, LPC) and encoding types.

Main Results:

• Younger adults exhibited significant SMEs across multiple ERP components for both encoding types.
• Older adults showed SMEs in earlier components (P2, N3) but reduced SMEs in later components (P550, LPC), especially for perceptual encoding.
• Larger frontal and central SMEs in younger adults during LPC latency were observed, irrespective of encoding type.

Conclusions:

• Aging significantly impacts memory encoding, with a more pronounced effect on perceptual than semantic processing.
• The age-related decline in SME is linked to difficulties in updating and maintaining representations, potentially due to frontal lobe functional changes.
• ERPs provide valuable insights into the neural mechanisms underlying age-related memory deficits.