Neuroscience 2000 Abstract
| Presentation Number: | 603.12 |
|---|---|
| Abstract Title: | Differential genetic contribution to variation in hippocampal and temporal horn volume: an MRI study of elderly twin men. |
| Authors: |
Sullivan, E. V.*1
; Pfefferbaum, A.2
; Swan, G. E.2
; Carmelli, D.2
1Dept Psychiatry, Stanford University, Stanford, CA 2SRI International, Menlo Park, CA |
| Primary Theme and Topics |
A. Development and Regeneration - 20. Cerebral cortex and limbic system |
| Secondary Theme and Topics | J. Disorders of the Nervous System and Aging<br />- 121. Genetic models |
| Session: |
603. Cerebral cortex and limbic system: development and regeneration II Poster |
| Presentation Time: | Wednesday, November 8, 2000 11:00 AM-12:00 PM |
| Location: | Hall G-J |
| Keywords: | genetics, aging, twin, Alzheimer |
The hippocampus is critical for consolidation of new information. Unless exposed to neurodegenerative conditions, its adult volume changes little with aging, possibly owing to regional neurogenesis. Continued structural modification could render the hippocampus vulnerable to cumulative environmental events, especially when measured in late adulthood. We investigated the contributions of genes and environment to MRI-derived hippocampal and temporal horn volumes in 44 monozygotic (MZ) and 40 dizygotic (DZ) elderly male twin pairs, 68-78 years. Neither hippocampal volume correlated with age (left r=.02, right r=.07), whereas temporal horn volume/age correlations were significant even in this restricted age range (left r=.20, right r=.23, p<.01). Intraclass correlations (ICC) for each twin zygosity were significant and greater in MZ than DZ pairs. For total hippocampal volume ICCs were .50 in MZ and .38 in DZ, whereas for temporal horn ICCs were .77 in MZ and .43 in DZ. Maximum likelihood model fitting revealed that only 29%-40% of hippocampal volume variance was due to genetic influences. By contrast, 63%-65% of temporal horn variance was accounted by genetic influences. These results suggest a differential contribution of genetic and environmental influences to these two adjacent brain structures in old age. The manner in which the brain responds to the environment with advancing age is highly genetically determined for temporal horn volume, which dilates with aging and disease, but is less for hippocampal volume, which remains relatively unchanged throughout adulthood life.
Supported by HL51429,AA05965,AA10723,MH58007
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2000 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2000. Online.
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