Meeting Abstract

53.3  Sunday, Jan. 5 14:00  Glucocorticoids and complex natural stimuli enhance adult neurogenesis in weakly electric fish. DUNLAP, KD; Trinity College kent.dunlap@trincoll.edu

Neurogenesis in the adult brain responds to both internal neuroendocrine signals and external sensory stimuli. In most species, glucocorticoids and external stimuli that elevate glucocorticoids inhibit neurogenesis. Here I present research showing that, in electric fish, social interaction simultaneously elevates glucocorticoids, increases aggressive electric signaling (chirping) and stimulates neurogenesis in brain regions associated with chirping. Blocking glucocorticoid action pharmacologically abolishes chirping and reduces socially elevated neurogenesis. These studies indicate that elevated glucocorticoid activation is required for increasing aggressive signaling and contributes to social enhancement of neurogenesis. In field studies, I demonstrate that fish facing complex natural stimuli, particularly during the breeding season, show much greater neurogenic rates throughout the brain (compared to laboratory housed fish). This global enhancement of neurogenesis in the breeding season is likely due to seasonal changes in temperature or daylength, but regionally-specific enhancement of neurogenesis in brain areas associated with electrocommunication is likely due to elevated social interaction during the breeding season. Both these sets of studies illustrate the value of a Wingfieldian approach to 1) understanding species diversity in hormone, brain and behavior relationships and 2) examining these relationships in free-living animals.