The smolt brain model: Unraveling nature´s regulation of neural plasticity

Limitations of neural plasticity in mammals make them vulnerable to insult with irreversible damage. We have discovered that the salmon brain undergoes a unique dramatic period of structural and chemical change mid-life during parr-smolt transformation (s moltification). Our main research goal has been to identify and characterize salmon models that can be used to elucidate the mechanisms that promote the brain to change. We found a unique landlocked salmon model that is hypoendocrine with dampened neural and endocrine development, which we recently used to demonstrate a definitive role of thyroid hormones in the development of the brain during smoltification (Ebbesson et al 2011). While our understanding of these processes has begun to reveal exciting new information, the molecular mechanisms that trigger and limit the brain to change remain largely elusive. Recent advances in the salmon genome project, the relatively inexpensive sequencing technology and accessible bioinformatics and our previous charact erisation of these unique models make it timely to use a broader molecular approach to address these questions. We will employ global and targeted approaches, integrating neural and plasma bioinformatics on established salmon models with different develop mental profiles to experimentally explore the molecular mechanisms regulating when and to what degree the brain changes during smoltification. This project will provide new insights into the molecular mechanism regulating neural plasticity in vertebrates. In addition to addressing the fundamental neuroscience questions, the present project will contribute substantially to our understanding of seasonal events, including smoltification.