Effects of aging on transient and sustained successful memory encoding activity

Nancy A. Dennis, Sander Daselaar, Roberto Cabeza

Research output: Contribution to journalArticlepeer-review

95 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)1749-1758
Number of pages10
JournalNeurobiology of Aging
Issue number11
StatePublished - Nov 2007

All Science Journal Classification (ASJC) codes

  • General Neuroscience
  • Aging
  • Clinical Neurology
  • Developmental Biology
  • Geriatrics and Gerontology


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