Effects of aging on transient and sustained successful memory encoding activity.

Journal Article (Journal Article)

Event-related fMRI studies have investigated age-related changes in encoding by identifying greater activity for items that are later remembered than for those that are forgotten (difference in memory, or Dm). The present study used hybrid blocked/event-related analyses to distinguish between transient Dm versus sustained Dm. Dm was identified as parametric increases in encoding activity as a function of a combined subsequent memory/confidence scale. Dm was measured in each trial (transient activity) and in blocks of eight trials (sustained activity). Transient Dm analyses showed age-related reductions in the left hippocampus but increases in left prefrontal cortex (PFC). Sustained Dm analyses showed age-related reductions in right PFC, but no region showing increased activity in older adults. These findings suggests that during semantic classification older adults show less spontaneous hippocampal-mediated encoding processes, but greater PFC-mediated semantic processes. Additionally, the decline in sustained Dm in PFC may involve age-related deficits in sustained attention that impact encoding processes. The results underscore the importance of investigating aging effects on both transient and sustained neural activity.

Full Text

Duke Authors

Cited Authors

  • Dennis, NA; Daselaar, S; Cabeza, R

Published Date

  • November 2007

Published In

Volume / Issue

  • 28 / 11

Start / End Page

  • 1749 - 1758

PubMed ID

  • 16919850

Pubmed Central ID

  • PMC3691865

Electronic International Standard Serial Number (EISSN)

  • 1558-1497

International Standard Serial Number (ISSN)

  • 0197-4580

Digital Object Identifier (DOI)

  • 10.1016/j.neurobiolaging.2006.07.006


  • eng