Octopuses, with their endlessly flexible arms, their vertebrate-like eyes, and their sophisticated behaviors are a source of ongoing fascination to scientist and public alike. Octopus brains are large, with many lobes, and from a distance look much more like the brain of an insect or crab than that of a fish or mammal. How the connections of the octopus brain are organized is unknown, so researchers can only begin to guess how octopuses control their arms or learn how to see. The research aim of this project is to study octopus brain circuitry with the tools of modern molecular cell biology in order to understand how the largest invertebrate brains are organized. The broader impacts of this research include the participation of high school and College students in octopus research each summer and the training of graduate students in comparative neuroscience. Research findings will be incorporated into an evolutionary neurobiology teaching module that will be offered in two introductory courses on the fundamentals of neuroscience at the University of Chicago, Marine Biological Laboratory. The Ragsdale laboratory engages directly in public outreach on octopus brain biology, behaviors and evolution. The forums for this outreach include laboratory tours for local high school students, internet video presentations, and feature stories on Science blog sites.
A modern investigation of the neural bases of cephalopod behavior depends on neuroanatomical and genomic databases, ideally ones for a model organism. The Ragsdale laboratory has identified a candidate model cephalopod, Octopus bimaculoides. This project will describe the systems neuroanatomy of O. bimaculoides, including its molecular organization with transcriptome-Âbased gene expression analysis. The proposed experiments focus on two systems best understood from lesion and stimulation studies: the axial nerve cords of the arms (Aim 1) and the learning and memory lobes (LMLs) of the supraesophageal brain (Aim 2). Aim 1 will ask how the sensory-Âmotor circuits of the arms are organized. Aim 2 will study the systems architecture of the LMLs. In many taxa, learning and memory organs feature orthogonal arrays of neuronal processes that form longitudinal zones. Such organization has been found in insect mushroom bodies and the vertebrate cerebellum. Findings with the Golgi method suggest that octopus LMLs also have orthogonally organized connections, but to date, no zonal organization has been reported. Aim 2 of this project will use techniques of modern neuroscience to determine how the octopus LML is organized.
