Octopuses and other cephalopods are voracious marine predators. Their success relies on structures not found in other invertebrates, including large brains, eyes of great acuity and prehensile arms. In addition, octopuses are intelligent problem-solvers with mammal-like memory skills. The goal of this research proposal is to understand how the octopus brain is organized, and to compare its structure with that of vertebrates, including mammals. The approach is to analyze the large-scale molecular architecture of the octopus brain and to trace the octopus brain circuitry with cellular methods. The expected results include a map of the molecular organization of the octopus brain and an outline of circuits by which the octopus brain receives and processes sensory information and controls its eight arms. Surprisingly, given the great interest in octopuses and their intelligence, their nervous systems have not been studied with modern neuroscience techniques. The major impact of this work will be to give insight into how a large non-vertebrate nervous system can be organized. These findings will be relevant to fields stretching from evolutionary biology to robotic control and computer science. Because of the great enthusiasm of the public for octopuses, it is anticipated that the findings of this project can be incorporated in K-12 educational and other outreach programs that introduce students to the study of brain and behavior. This project will generate octopus DNA sequence data that will be shared with the community through NCBI web-based archives.
Cephalopod molluscs (octopus, cuttlefish, squid) have the largest brains of all invertebrates. In the adult octopus, the brain comprises over two-dozen major lobes with 100 million neurons. There are an additional 300 million neurons in the nerve cords that run down the middle of each of the octopus arms. It is widely thought that the size and structure of the octopus nervous system account for the sophisticated behaviors these animals display. How this large nervous system is organized has, however, been little explored with modern neurobiological methods. In this project we employed an emerging cephalopod model organism, the California Two-spot Octopus (Octopus bimaculoides), to investigate the circuitry and molecular organization of the octopus brain and the nerve cords of the octopus arms. Our results include a demonstration that the learning and memory lobes of the octopus brain have a much more complex organization than was previously suspected. In addition we have developed the octopus visual system as a physiological model for cephalopod functional magnetic resonance imaging (fMRI) studies. The broader impacts of this work include catalyzing the establishment of the Cephalopod Sequencing Consortium (CephSeq). The goals of CephSeq include the rapid advancement of cephalopod genomics, the application of cephalopod genomics to fisheries science, materials science and biomedical research, and the broad dissemination of cephalopod biology and genomics research to the public, including K-12 students.
