Velíšková lab · New York Medical College · STAR program · 2018
Estrogen and the dentate gyrus: response to spatial and environmental novelty
Roughly 200,000 oophorectomies a year in the United States produce surgical menopause and a sudden drop in estradiol; many of those women then take estrogen partly for cognition. Estrogen receptors are dense in the dentate gyrus, the structure behind pattern separation, and the lab had already shown estradiol altering long-term potentiation there in vitro. What that did to behavior was open.
Status. Written up for the Junior Science and Humanities Symposium and presented as a poster. My first study — run as a high-school student through the STAR program at New York Medical College.
The question
Does estradiol replacement after ovariectomy change how animals respond to spatial and environmental novelty — the behavior the dentate gyrus is thought to support?
How it is being done
- Eighteen ovariectomized Sprague-Dawley rats, replaced with β-estradiol (2 µg/day for four days) or oil vehicle, assigned at random.
- Environmental change: habituation across three trials in a circular arena with two objects 30 cm apart, then a single trial in a new square arena with the objects unmoved.
- Metric change: the same habituation, then the objects moved from 30 cm to 50 cm apart.
- Exploration scored from overhead video with ANY-maze, plus manual counts of rearing, object exploration and zone crossings.
What it shows so far
- Estradiol-replaced animals explored significantly less after the environmental change than oil-injected controls (p = 0.028).
- A similar direction followed the metric change.
- Together: estradiol modulates dentate-gyrus-mediated responses to novelty — the behavioral counterpart of the LTP differences the lab had recorded in vitro.
An honest limitation, noted at the time. The metric change was run on the same day as the environmental change, so the animals were no longer meeting a novel environment when it began. The write-up called for repeating it on its own day with new animals.
Materials
What comes next
Eight years later the same question — what estrogen does when it is taken away, and what happens when it is given back — is the subject of the vaginal-estrogen study on this site.
This page grows as the work does.