Feb 17, 2012
The mammalian limbic system is a group of brain structures involved in memory formation and emotion processing. The amygdala, a component of this system, coordinates stress responses. The amygdala can be split into three main divisions: the basolateral (BLA), medial (MeA), and central (CeA) nuclei. Although these divisions are seen across tetrapods, researchers have yet to determine if they are also present in evolutionary ancestors of the tetrapods
My research will use tract-tracing to examine the connectivity of a potential homologue (structural equivalent) of the CeA in a teleost fish, the goldfish. Teleosts share their most recent common ancestor with tetrapods, thereby serving as a model for investigating tetrapod amygdalar origins. Previous studies advocate a teleostean homologue of the BLA, but homologues for the CeA and MeA remain unidentified. Should the structure I examine demonstrate connections similar to the mammalian CeA, these findings will suggest that teleosts possess the same basic amygdalar divisions seen in mammals. Determining this limbic evolution may facilitate improved understanding of amygdalar roles (i.e. motor or sensory) in diseases such as Obsessive-Compulsive Disorder.