Behavioral, genetic and neuronal mechanisms of olfactory imprinting in zebrafish II
Imprinting is a learning process during early development that is limited to a short period of time and leads to irreversible changes in behavior. Six-day-old zebrafish larvae learn olfactory cues of siblings during a 24 h time window, which results in a preference for kin over non-kin later in life. The aim of this study is to characterize sensory signals, the genetic factors, and the neurobiological processes underlying this olfactory imprinting. We identified MHC peptides that can trigger imprinting and kin recognition in a specific zebrafish line. Using these signals and the responsive fish line we will analyze the representation of MHC peptides in the olfactory bulb and higher brain areas. We will create transgenic fish of the imprintable line that express a genetically encoded calcium indicator (GCamp2.0/3.0) and measure odor-evoked activity by 2-photon calcium imaging. In parallel, we will use newly developed methods for double-labeling of egr1 with fluorescent in situ hybridization (FISH) and tyrosine hydroxylase immunohistochemistry (THIHC) to identify brain areas and cells that may differ in their activity in imprinted and non imprinted fish. These experiments are expected to yield novel insights into the neuronal circuits and plasticity processes underlying olfactory imprinting.