Meeting Abstract
The boneless bodies of octopus, squid, and other cephalopods owe their structural integrity and functional diversity in part to exquisitely arranged muscle fibers that permeate, shape, and power the body. The arms and suckers of octopus, for instance, are exceptional in both prehensile dexterity and in strength. The suckers themselves are highly engineered modular structures that operate individually but also act with local coordination, each sucker having its own little ganglion that wires into an overhead nerve cord running through the arm. The suckers are mechanical in their suction and also serve tactile and chemosensory functions. The sophistication, modularity, and hierarchy of the arms and suckers system, and its potential interface with neuroscience, biomechanics, and robotics is enticing but powerful tools for live and whole-mount imaging are largely unestablished. Recent advances in microscope systems, dyes, and clearing agents enable imaging of sub-cellular structure in the context of gross anatomical features, for instance, the muscle fibers and ganglia of entire arm suckers in octopus hatchlings. Here we characterize the spatial arrangement of nerves and muscles in whole-mount arms of different species of cephalopods using fluorescent dye and label-free methods and various imaging approaches, including confocal, light sheet, and polarized light microscopy. In addition, we develop a behavioral assay to capture sucker dynamics of octopus hatchlings during the process of grip and release from a substrate, a first step to enabling readouts of neural and muscular activity in suckers using genetically encoded fluorescent biosensors, like GCaMP to visualize calcium dynamics.
