9728543 Dohanich One of the most fundamental questions in neuroscience is how the CNS is able to store and retrieve information. It is clear that whatever the actual mechanisms that underlie learning, whether structural, physical, or even functional, they must involve chemical changes. The steroid hormone, estrogen, has been shown to promote the growth of brain structures, modulate brain biochemistry, and affect performance on tasks of learning and memory. Moreover, estrogen modulates the activity of a number of neurotransmitters including acetylcholine which has been hypothesized as a transmitter of learning. Indeed, Dr. Dohanich has found that estrogen effects on memory become most apparent when acetylcholine systems have been compromised pharmacologically. Using a variety of behavioral paradigms, Dr. Dohanich will now began to decipher the complex role of the ovarian hormones, estrogen and progesterone. on spatial learning and memory. Moreover, using quantitative autoradiographic techniques, he will examine the effects of estrogen and progesterone on cholinergic receptors in brain regions important for memory. The results from these studies will determine both the conditions and the mechanisms under which estrogen has memory enhancing effects. These studies are especially important and timely given the recent reports suggesting that the presence of estrogen in women is correlated with improved memory and a reduced incidence of Alzheimer's Disease. Moreover, the results from this project will greatly enhance our understanding of the fundamental interrelationships of ovarian hormones, cholinergic neurotransmission, and learning and memory, an area which is filled with speculation while lacking important data.
