Hormonal and Environmental Influences on Maternal Behavior

这些实验旨在探索荷尔蒙对行为产生影响的确切途径。我们知道，与生殖相关的荷尔蒙对人类和其他动物的行为有深远的影响。施奈德博士将研究怀孕期间产生的类固醇激素，这些激素对怀孕期间和后代出生后女性的母性行为有可测量的影响。施奈德博士将在这个项目中使用家鼠，因为在怀孕期间，雌性老鼠通常会增加自己的巢穴大小，为后代的出生做准备。这种筑巢行为的增加可以在未怀孕的雌性身上模拟，方法是给她注射怀孕类固醇黄体酮。施奈德博士认为，孕激素通过大脑机制改变了母亲的行为，而大脑机制也参与了体温的调节。(家鼠一年四季都在生孩子，即使是在寒冷的冬天，它们的幼鼠出生时也没有能力维持自己的体温。)为了揭示体温调节和母体行为控制之间的联系，施奈德博士将(1)测量在非常精确的脑区植入黄体酮的小鼠的筑巢、母体护理和体温，以显示控制母体行为和体温调节的大脑机制之间可能存在重叠的地方。以及(2)测试不同类固醇在这些大脑部位的作用，看看同样的类固醇是否会同时影响母体的筑巢和体温。施奈德博士还将测量血液中类固醇的水平，以找出黄体酮对大脑的作用是否会改变卵巢或肾上腺自然产生的类固醇的分泌。施奈德博士的研究将有助于展示荷尔蒙如何为母亲的分娩和子女的照顾做好准备。更广泛地说，这些研究可能会更好地理解类固醇激素(通常用于各种原因：节育、不孕、更年期、过敏)对人类行为和生理产生主要和副作用的机制。

These experiments are designed to explore the exact routes by which hormones have their effects on behavior. We know that the hormones associated with reproduction have profound effects on the behavior of humans and other animals. Dr. Schneider will work with steroid hormones that are produced during pregnancy and have measurable effects on the maternal behavior of the female during pregnancy and after the birth of her offspring. Dr. Schneider will use house mice for this project because during pregnancy the female typically increases the size of her nest in preparation for the birth of her offspring. This increase in nesting behavior can be mimicked in a nonpregnant female by injecting her with the pregnancy steroid, progesterone. Dr. Schneider believes that progesterone changes the mother's behavior by way of brain mechanisms that are also involved in the regulation of body temperature. (House mice give birth all year round, even during cold winters, and their young are born without the ability to maintain their own body temperature.) To unravel the connection between the regulation of body temperature and the control of maternal behavior, Dr. Schneider will (1) measure nesting, maternal care, and body temperature in mice that have progesterone implants in very precise brain areas to show where there may be overlap among the brain mechanisms controlling maternal behavior and temperature regulation, and (2) test the effects of a variety of steroids in these brain sites to see if the same ones influence both maternal nesting and body temperature. Dr. Schneider will also measure the levels of steroids in the blood to find out if the action of progesterone on the brain changes the secretion of naturally occurring steroids from the ovaries or adrenal glands. Dr. Schneider's research will help to show how hormones prepare the mother for the birth and care of her offspring. More generally, these studies may provide a better understanding of the mechanisms by which steroid hormones (commonly prescribed for a variety of reasons: birth control, infertility, menopause, allergies) produce their primary and side effects on human behavior and physiology.