Peripheral infection and aging interact to impair hippocampal memory consolidation

Neurobiol Aging. 2006 May;27(5):723-32. doi: 10.1016/j.neurobiolaging.2005.03.010.


We report that a peripheral injection of Escherichia coli produces both anterograde and retrograde amnesia in 24 month old, but not 3 month old rats for memories that depend on the hippocampus, that is, memory of context, contextual fear, and place learning. The anterograde effect was restricted to measures of long-term memory. Short-term memory was not affected, nor did E. coli produce amnesia for auditory-cue fear conditioning. There were no age related effects on memory in vehicle-treated rats. In addition to these age-related cognitive effects of E.coli, we report that it produced a marked increased in IL-1beta levels in the hippocampus, but not in parietal cortex or serum. These findings support the hypothesis that age is a vulnerability factor that increases the likelihood that an immune challenge will produce a cognitive impairment. It is possible that this cognitive vulnerability is mediated by age-related changes in the glial environment that results in an exaggerated brain pro-inflammatory response to infection.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acoustic Stimulation
  • Aging / physiology*
  • Aging / psychology
  • Amnesia, Anterograde / psychology
  • Amnesia, Retrograde / psychology
  • Animals
  • Conditioning, Psychological / physiology
  • Escherichia coli Infections / immunology
  • Escherichia coli Infections / physiopathology*
  • Escherichia coli Infections / psychology
  • Fear
  • Hippocampus / physiopathology*
  • Interleukin-1 / metabolism
  • Male
  • Maze Learning / physiology
  • Memory Disorders / etiology
  • Memory Disorders / physiopathology*
  • Memory Disorders / psychology
  • Rats


  • Interleukin-1