and marmoset monkeys. Gould and her colleagues have shown that social stress inhibits cell production in these three species in a series of studies. Furthermore, they have discovered that exposure of adult rats to the odors of natural predators, but not other novel odors, suppresses the proliferation of cells in the dentate gyrus. This effect was found to be dependent on adrenal steroids because the prevention of the stress-induced rise in glucocorticoids (by adrenalectomy and replacement with low-dose corticosterone in the drinking water) eliminated the inhibitory effect of fox odor on cell production. The importance of complex environments Gould's team has observed that many new cells in the hippocampus of adult rats and monkeys do not survive in animals living under standard laboratory conditions. In rodents, they discovered that these cells can be rescued by exposing the animals to more complex environments. These results they believe reflect the deprived laboratory conditions in which experimental animals live. This they also suspect is a phenomenon, that is probably, even more pronounced in primates with higher social needs than in rodents. The Gould team is continuing to explore this issue by examining the brains of adult rats living in a visible burrow system and adult monkeys living in semi-naturalistic conditions with opportunities for foraging and other natural activities. The functional role of new neurons Although the function of new neurons in the adult brain is as yet unknown Gould and her colleagues have begun to conjecture possibilities. So many new neurons are generated in the hippocampus and these cells appear to be a sensitive to experience, therefore it seems likely to the Gould team that they participate in hippocampal function. They are exploring the possibility that new neurons participate in two functions of the hippocampus, learning and modulation of the stress response. They have shown that learning enhances the number of new neurons but only under certain conditions. Furthermore, they have discovered, experimental depletion of new neurons is associated with impairment in certain types of learning but not others. A decrease in the number of new neurons following treatment with anti-mitotic drugs impairs trace eye blink conditioning but not spatial learning in a Morris water maze, both hippocampal-dependent tasks. Honors and awards Gould received a multitude of awards throughout the duration of her career. From 1989 to 1991, Gould was awarded an NRSA Individual postdoctoral fellowship. From 1991 to 1992, she was awarded