The objective of this study is to evaluate the neurobiological effects of hormone therapy
(HT) in healthy early postmenopausal women. The studies proposed in this project seek to
define the association between different hormone forms (estradiol only and progesterone only)
versus placebo on brain functional measures. The functional measures will include the
performance of the volunteers on a comprehensive neuropsychological testing battery, and the
brain functional responses to episodic memory (verbal and non-verbal) challenges as well as
emotional processing determined with functional magnetic resonance imaging (fMRI).