Showing papers by "Michael J. Baum published in 2011"
TL;DR: In the present experiments, administering estradiol prepubertally significantly enhanced the ability of ArKO female mice to display lordosis behavior in response to ovarian hormones administered later in adulthood, whereas treatment over an earlier postnatal period had no effect.
Abstract: The classic view of brain and behavioral sexual differentiation holds that the neural mechanisms controlling sexual behavior in female rodents develop in the absence of ovarian sex hormone actions. However, in a previous study, female aromatase knock-out (ArKO) mice, which cannot convert testosterone to estradiol, showed deficient male-oriented partner preference and lordosis behaviors in response to adult ovarian hormones, raising the possibility that estradiol may contribute to the development of these female sexual behaviors. In the present experiments, administering estradiol prepubertally [between postnatal day 15 (P15) and P25] significantly enhanced the ability of ArKO female mice to display lordosis behavior in response to ovarian hormones administered later in adulthood, whereas treatment with estradiol over an earlier postnatal period (P5–P15) had no such effect. Treatment of ArKO females with estradiol between P15 and P25 also rescued their later preference to approach distal cues from an intact male over an estrous female. ArKO females also displayed significantly less female-directed (male-typical) mounting behavior than wild-type control females when treated with testosterone in adulthood. Prepubertal estradiol treatment failed to reverse this deficit in ArKO females, whereas earlier postnatal estradiol augmented later mounting in both genotypes. Our results provide new evidence for an organizing role of prepubertal estradiol in the development of neural mechanisms that control female-typical sexual behavior.
97 citations
TL;DR: A whole-mount, flattened cortex preparation was developed to compare profiles of axonal projections from main olfactory bulb (MOB) mitral and tufted (M/T) cells and found that M/T cells in the AOB sent axons primarily to the medial and posterior lateral cortical amygdala, with minimal branching into the piriform cortex.
Abstract: A whole-mount, flattened cortex preparation was developed to compare profiles of axonal projections from main olfactory bulb (MOB) and accessory olfactory bulb (AOB) mitral and tufted (M/T) cells. After injections of the anterograde tracer, Phaseolus vulgaris leucoagglutinin, mapping of labeled axons using a Neurolucida system showed that M/T cells in the AOB sent axons primarily to the medial and posterior lateral cortical amygdala, with minimal branching into the piriform cortex. By contrast, M/T cells in the MOB displayed a network of collaterals that branched off the primary axon at several levels of the lateral olfactory tract (LOT). Collaterals emerging from the LOT into the anterior piriform cortex were often observed crossing into the posterior piriform cortex. M/T cells in the dorsal MOB extended fewer collaterals from the primary axon in the rostral LOT than did M/T cells from the anterior or ventral MOB. MOB M/T cells that projected to the medial amygdala did not do so exclusively, also sending collaterals to the anterior cortical amygdala as well as to olfactory cortical regions. This arrangement may be related to the ability of social experience to modify the response of mice to volatile pheromones detected by the main olfactory system.
67 citations
TL;DR: Any sexually dimorphic behavioral or neuroendocrine responses to male urinary volatiles likely depend on the differential processing of these odor inputs in the AOB and/or other downstream forebrain structures after their detection by the main olfactory system.
51 citations
TL;DR: A more robust induction of Fos was observed in female mice which had direct nasal contact with dominant male urinary odors, and a greater activation of the accessory olfactory pathway by dominant male urine suggests that there are differences in the nonvolatile components of dominant versus subordinate male urine that are detected by the vomeronasal organ.
41 citations
TL;DR: It was depressing to see the government’s Advisory Board on the Registration of Homeopathic Products advertising for four expert and “eminent members of their profession” who can “assimilate complex scientific theories”.
Abstract: At a time of austerity cuts, when treatments that work should be protected, it was depressing to see the government’s Advisory Board on the Registration of Homeopathic Products advertising for four expert and “eminent members of their profession” who can “assimilate complex scientific …
11 citations