Steroids and Plasticity
- Alyssa L. PedersenAlyssa L. PedersenAmerican University
- and Colin J. SaldanhaColin J. SaldanhaAmerican University, Department of Neuroscience
Given the profound influence of steroids on the organization and activation of the vertebrate central nervous system (CNS), it is perhaps not surprising that these molecules are involved in processes that restructure the cytoarchitecture of the brain. This includes processes such as neurogenesis and the connectivity of neural circuits. In the last 30 years or so, we have learned that the adult vertebrate brain is far from static; it responds to changes in androgens and estrogens, with dramatic alterations in structure and function. Some of these changes have been directly linked to behavior, including sex, social dominance, communication, and memory. Perhaps the most dramatic levels of neuroplasticity are observed in teleosts, where circulating and centrally derived steroids can affect several end points, including cell proliferation, migration, and behavior. Similarly, in passerine songbirds and mammals, testosterone and estradiol are important modulators of adult neuroplasticity, with documented effects on areas of the brain necessary for complex behaviors, including social communication, reproduction, and learning. Given that many of the cellular processes that underlie neuroplasticity are often energetically demanding and temporally protracted, it is somewhat surprising that steroids can affect physiological and behavioral end points quite rapidly. This includes recent demonstrations of extremely rapid effects of estradiol on synaptic neurotransmission and behavior in songbirds and mammals. Indeed, we are only beginning to appreciate the role of temporally and spatially constrained neurosteroidogenesis, like estradiol and testosterone being made in the brain, on the rapid regulation of complex behaviors.