Female rats learn trace memories better than male rats and consequently retain a greater proportion of new neurons in their hippocampi

Learning increases the survival of new cells that are generated in the hippocampal formation before the training experience, especially if the animal learns to associate stimuli across time [Gould E, Beylin A, Tanapat P, Reeves A, Shors TJ (1999) Nat Neurosci 2:260–265]. All relevant studies have been conducted on male rats, despite evidence for sex differences in this type of learning. In the present study, we asked whether sex differences in learning influence the survival of neurons generated in the adult hippocampus. Male and female adult rats were injected with one dose of bromodeoxyuridine (BrdU; 200 mg/kg), to label one population of dividing cells. One week later, half of the animals were trained with a temporal learning task of trace eyeblink conditioning, while the other half were not trained. Animals were killed 1 day after training (12 days after the BrdU injection). Hippocampal tissue was stained for BrdU and a marker of immature neurons, doublecortin. Both sexes learned to emit the conditioned eyeblink response during the trace interval. As a consequence, more new neurons remained in their hippocampi than in sex-matched controls. In individual animals, the number of surviving cells correlated positively with asymptotic performance; those that expressed more learned responses retained more new neurons. However, animals that learned very well retained even more new cells if they required many trials to do so. Because females emitted more learned responses than males did, they retained nearly twice as many new cells per unit volume of tissue. This effect was most evident in the ventral region of the hippocampal formation. Thus, sex differences in learning alter the anatomical structure of the hippocampus. As a result, male and female brains continue to differentiate in adulthood

Religion and Coping with Trauma: Qualitative Examples from Hurricanes Katrina and Rita

In this article, we consider the intersection of religious coping and the experience of Hurricanes Katrina and Rita in a lifespan sample of adults living in South Louisiana during the 2005 storms. Participants were young, middle-age, older, and oldest-old adults who were interviewed during the post-disaster recovery period. Qualitative analyses confirmed that three dimensions of religion were represented across participants\u27 responses. These dimensions included: 1) faith community, in relation to the significant relief effort and involvement of area churches; 2) religious practices, in the sense of participants\u27 behavioral responses to the storms, such as prayer; and c) spiritual beliefs, referring to faith as a mechanism underlying individual and family-level adjustment, acceptance and personal growth in the post-disaster period. Implications for future disaster preparedness are considered