Professor and Director of the Initiative on Neurosciences
Department of Biology
Host: Maria Tosches
Title: The four Fs of neural circuits underlying nudibranch behavior: Form, function, phylogeny, and fortune
Abstract: Although neuroscience emphasizes the relationship between form and function in the study of the neural basis of behavior, two other factors play important roles: phylogeny and fortune. Behavior (function) is produced by neurons and synapses (form). However, the ultimate explanations for particular forms and functions are rooted in their phylogeny. Fortune comes into the picture because all unexpected discoveries arise from chance. I will talk about the neural circuits underlying the swimming behaviors in nudibranch molluscs. These central pattern generator (CPG) circuits are composed of large individually identified neurons, which in one species contains only four neurons. We understand the precise mechanism by which these neurons generate a simple motor pattern. However, a different mechanism is used by the same neurons in another species to produce the same behavior. To gain a deeper understanding of how neurons gain their identities and their species-typical connectivity, my lab switched to a nudibranch species that could be raised in the lab. I will talk about how our efforts to map all of the neurons and their gene expression led to a stroke of good fortune, which diverted us from the small number of large neurons to the large number of small neurons that make up the so-called “peripheral” nervous system. We found that there are far more neurons in peripheral ganglia than in what we consider to be the brain. Fortunately, this is leading us to Form new ideas about how this PHylum Functions.