No abstract

Prednisone treatment for infertility and subsequent pregnancy maintenance in humans resulted in a significant decrease in the birth weight of full-term infants and a marked increase in the percentage of newborn infants weighing 2500 grams or less, that is, "light for dates" in comparison to control offspring. A parallel experiment with mice indicated that the reduction of birth weight was caused by exposure to corticosteroids rather than to maternal disease or malfunction.

No abstract

Olfactory bulb removal eliminated maternal behavior in lactating and in virgin mice. The results are in contrast to the generally accepted concept of multisensory control of mammalian maternal behavior.

Early data and theories suggested that the properties of rewarding electrical stimulation of the brain (ESB) differ from those of natural rewards, such as food or water. It is contended here that such differences are solely due to differences in deprivation and training conditions, rather than to inherent differences in the rewards. Therefore, it is proposed that ESB has the same properties as other rewards and that its motivational properties are inherent in its reinforcement properties in the form of incentive motivation, rather than in the induction of drive energization. Data testing the model are reviewed and are found to support the incentive position. It is further suggested that to the extent that brain stimulation can maintain behavior in the absence of deprivation the laws for incentive independent of deprivation conditions can be found using brain stimulation.