8-Armed Symphony: Roger Hanlon Lands Grant to Illuminate Neural Sensing & Control of Octopus Arms

Confocal microscopy image of a young octopus arm with selective stains to determine its 3D architecture. Credit: Stephen Senft, Hanlon Lab

The octopus arm and its arsenal of suckers enable an extreme range of sensory and motor capabilities, all within an appendage that has unparalleled flexibility and strength. Octopus appendages perform many functions that humans wish to emulate for applications in society, industry, medicine, and defense. A key biological challenge is to unravel the mechanisms of neural sensing and control of an individual arm and its coordination with adjacent arms.

Recently, the U.S. Department of Defense/Office of Naval Research awarded a three-year grant to MBL Senior Scientist Roger Hanlon (principal investigator) to illuminate the mechanisms of sensorimotor control of octopus arms. Co-PIs on the grant are former MBL co-director Melina Hale of University of Chicago and Trevor Wardill of University of Minnesota/MBL Whitman Center. Joining Hanlon to work on the research in the MBL Bell Center are Kendra Buresch and Stephen Senft.

This research can have significant applications, such as the design of soft, flexible, strong robotic arms that can locomote, grasp/release, and sense chemicals and physical materials. Soft robotic arms could enable, for example, search-and-rescue medicine delivery to people in collapsed buildings. When miniaturized, soft, flexible devices for medical diagnosis or treatment could be deployed, such as in the GI tract and the vascular system.

An octopus on the ocean floor. Credit Roger Hanlon
An octopus using chemotactile sensing with arms and suckers while foraging in nature. Credit: Roger Hanlon
Octopus experimental setup. Credit Roger Hanlon
Lab experimental design to test for touch and taste discrimination without visual input ("blind searching"). Credit: Roger Hanlon

The team’s central goal is to determine which octopus neural system components and control principles are critical for proper intra- and inter-arm coordination, particularly of (1) a single arm and its approximately 200 suckers; (2) one arm with the adjacent arms and suckers; and ultimately (3) all eight arms in concert. Eight-arm control is the most challenging, especially for complex maneuvers such as interception and prey capture within rock crevices, walking and crawling, or building structures for shelter.

Their ultimate experimental goal is to relate the sensory capabilities of octopus arms and suckers to motor and behavioral output by testing the relative independence and/or interdependence of individual peripheral arm ganglia vis-à-vis central nervous system control and coordination of eight arms. Anatomical, physiological, and behavioral data will be synthesized to explain the basic locomotory mechanics, active chemotactile sensing, and sensorimotor control system that operate the octopus’s eight arms.

Achievements will uncover new and refined mechanisms for the control of a networked system of flexible actuators, and inspire new models of high-dimensional control for future Department of Defense applications.