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Hormonal factors influencing adult neurogenesis
We have shown that glucocorticoids negatively regulate adult neurogenesis - removal of glucocorticoids by adrenalectomy stimulates adult neurogenesis while injections of corticosterone suppress adult neurogenesis. In some instances, however, elevated glucocorticoids are associated with either no change in adult neurogenesis or the opposite effect (increased adult neurogenesis), suggesting that other factors can interfere with the glucocorticoid response. We are currently investigating the influence of neuromodulators and growth factors on glucocorticoid responses.

Rewarding experience and protection from glucocorticoids

Our lab is interested in understanding how rewarding experiences can have health benefits despite activating systems associated with stress.  We have shown that a rewarding social experience (sexual experience) enhances adult neurogenesis and dendritic spine density.  These findings seem paradoxical since sexual experience also results in a large increase in circulating glucocorticoids, hormones that typically inhibit neuronal growth.  We are currently investigating the effects of sexual experience on hippocampal function.

Physical activity and structural plasticity in the hippocampus
Our lab studies the effects of physical activity on adult neurogenesis, dendritic architecture and dendritic spines in the hippocampus.  Running increases adult neurogenesis in the dentate gyrus and enhances dendritic spine density throughout the hippocampal circuitry. Some of these effects are modulated by the social context in which an animal lives. Ongoing studies are investigating the effects of running and stress on the activation of new neurons as well as the contribution of running-induced structural change to alterations in hippocampal function.
Aging, structural plasticity and hippocampal function
Our lab is interested in understanding the changes that occur in the hippocampus as a result of aging with an aim toward identifying conditions that minimize structural and functional decline.  We and others have demonstrated a decline in adult neurogenesis during midlife. We are currently investigating conditions that are capable of stimulating adult neurogenesis in older brains.

Maternal and paternal care
Parenting is a complex experience that is both stressful and enriching.  Our lab studies the influence of parenting on brain structure and function.  We have shown that parenting is associated with neuronal growth in the prefrontal cortex, findings that are consistent with living in an enriched environment.   We have also shown that maternal as well as paternal care result in a decrement in adult neurogenesis in the hippocampus.  These changes may contribute to some of the behavioral changes associated with parenting.



Adult neurogenesis outside of the hippocampus

We have also reported a lower level of adult neurogenesis (relative to the hippocampus) in the neocortex (this work remains controversial – see images and protocols for additional information about this issue).