UNIVERSITY OF SOUTHERN CALIFORNIA

We have developed and applied a set of tools that enables direct observation and spatial mapping of synapses using high-contrast selective plane illumination imaging of an endogenous postsynaptic density protein labeled with a recombinant GFP-coupled probe. Using these tools, we have observed changes in the microstructure of the pallium of larval zebrafish that occur during memory formation as a result of exposure to a novel classical conditioning paradigm that we developed. Surprisingly, we found that memory formation due to classical conditioning is associated with generation of new synapses, but not with systematic changes in the strengths of existing synapses.