Memory performance and the growth hormone/insulin-like growth factor axis in elderly: a positron emission tomography study: a positron emission tomography study

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The relationship between the growth hormone/insulin-like growth factor (GH-IGF)-I status and memory performance is studied in 24 elderly males and females, aged 75-85 years. Positron emission tomography (PET) was used to measure differences in regional cerebral blood flow during the performance of a delayed-non-match-to-sample (DNMTS) working memory task. Quality and speed of performance on the DNMTS task were measured separately for the easy items (3, 4 and 5 letters) and difficult items (6, 7 and 8 letters). Results were analyzed in two different groups based on the IGF-I level of the subjects (low or high IGF-I). Error rates on the working memory task were not different, but the high IGF-I group had shorter reaction times on the easy items. The high IGF-I group showed a significantly greater increase in cerebral blood flow in the left premotor cortex (easy items) and left dorsolateral prefrontal cortex (difficult items) compared to the low IGF-I group. It is concluded that elderly with high IGF-I levels are capable of faster working memory performance and increased recruitment of task-associated prefrontal regions. Copyright © 2005 S. Karger AG.
Original languageEnglish
Pages (from-to)31-40
Number of pages10
Issue number1
Publication statusPublished - 2005


  • Aged
  • Aged, 80 and over
  • Brain Mapping
  • Cerebral Cortex/blood supply
  • Cerebrovascular Circulation/physiology
  • Female
  • Functional Laterality/physiology
  • Geriatric Assessment
  • Human Growth Hormone/metabolism
  • Humans
  • Insulin-Like Growth Factor I/metabolism
  • Male
  • Memory, Short-Term/physiology
  • Neuropsychological Tests
  • Positron-Emission Tomography
  • Reaction Time/physiology
  • Statistics, Nonparametric

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