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Heritability of hippocampal size in elderly twin men: Equivalent influence from genes and environment
Author(s) -
Sullivan Edith V.,
Pfefferbaum Adolf,
Swan Gary E.,
Carmelli Dorit
Publication year - 2001
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.1091
Subject(s) - hippocampal formation , heritability , hippocampus , neuroscience , corpus callosum , twin study , brain size , brain structure and function , psychology , cognition , developmental psychology , biology , evolutionary biology , medicine , magnetic resonance imaging , radiology
Recent studies have established that environmental factors can modify hippocampal structure and enhance function in adult rodents, but the extent to which genes and the environment exert differential contributions to hippocampal structural integrity in humans is unknown. Here, we applied the twin model in a large sample of elderly twin men to examine in late life the balance of environmental and genetic effects on the size of the hippocampus in comparison with other brain structures. This study provides novel evidence that the volume of the hippocampus, as measured on MRI, is subject to substantially less genetic control than are comparison brain regions also measured: temporal horn volume, midsagittal area of the corpus callosum, and intracranial volume (ICV). In particular, about 60% of the temporal horn variance and 80% of the callosal and ICV variance was attributable to genetic influences, whereas only 40% of the hippocampal variance was attributable to genetic influences. These results suggest that environment, whether by itself or in interaction with genes, has the potential of exerting greater and possibly longer control in modifying hippocampal size than other brain regions that are under greater genetic control. Considering the potential of environmental modification of this structure suggested by lower heritability, the hippocampus appears well‐suited to support the dynamic processes of encoding and consolidation of new, declarataive memories. Hippocampus 2001;11:754–762. © 2001 Wiley‐Liss, Inc.