NGF trkA and p75

Larger cholinergic neuron may effect by
Gonadol hormone
- may be related to
-> hippocampus size
-> > functional maturity
Neonatal male rats
- testosterone -> estrogen in the brain
- develop larger hippocampus than
neonatal female rats
Neonatal female rats :
treated with either estrogen or
testosterone
-> > larger hippocampus
-> > become as proficient as male rats at
solving the spatial water maze
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Either circulating testosterone or estrogen,
has trophic effects to
- BFCN
- may affect both the functional and
structural plasticity of hippocampal
pyramidal neurons
Gender differences in decline of spatial
learning ability and brain aging
- differential status of gonadal hormone
levels at different stages in life
- Female rats
: declines ovarian function = > ~18 months
- Male rats :
: declines testicular function => ~12 months :
testosterone levels drop to about 50% of
baseline by 24 months of age
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Gonadal steroids are important for both
the function and integrity of hippocampal
neurons and their septal cholinergic
afferents
Sustained levels of estrogen in female
aging
- absence of BFCN atrophy
- less decline in spatial learning
performance
In this time, researcher did not monitor
levels of gonadal hormones in either of
aged groups during the aging process
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