Memory performance and the growth hormone/insulin-like growth factor axis in elderly: a positron emission tomography study.
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.
Arwert
Lucia I
LI
Department of Endocrinology, VU University Medical Center, Amsterdam, The Netherlands. l.arwert@vumc.nl
Veltman
Dick J
DJ
Deijen
Jan Berend
JB
Lammertsma
Adriaan A
AA
Jonker
Cees
C
Drent
Madeleine L
ML
D000368:Aged; D000369:Aged, 80 and over; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D015577:Geriatric Assessment; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography; D011930:Reaction Time / Q000502:physiology; D018709:Statistics, Nonparametric
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I