Living Machines 2022 / WORKSHOPS

Workshop 1. 19 July 2022

12:45 – 18:00 UTC

How do animal neuromechanical systems perform communication, coordination and control?


Roger Quinn, Professor,,
Hillel Chiel, Professor,, Case Western Reserve University

The purpose of this workshop is to compare and contrast how neuromechanical systems in animals from different phyla allow them to perform functions essential to their survival. The workshop first focuses on an overview on how the frequency of movement and size of libs can affect the control of locomotion (Dr. Gregory Sutton). The role of joint stresses and strains on control of limbed locomotion is then discussed (Dr. Matthew Tresch). A discussion of how to fit multiple parameters that are necessary for neuromechanical models provides useful guidance for others who are working in this area (Dr. Matthieu Chardon). New insights on insect walking will bridge between single neuron function and system performance of six-legged walking (Dr. Ansgar Büschges). To further understand sensory inputs to the insect leg, biomechanical and morphological studies of strain sensors (campaniform sensilla) clarify how sensors are integrated and can affect both control within and between legs (Dr. Gesa Dinges). The workshop should be of broad general interest to those studying the neural and mechanical basis of behavior and those interested in creating autonomous artificial devices inspired by animals. 

Program: talks

This workshop will focus on how animals’ neuromechanical systems solve problems that autonomous robots must solve. Thus, it should be of broad general interest to those studying the neural and mechanical basis of behavior and those interested in creating autonomous artificial devices inspired by animals.

“Limb control parameters are determined by size and frequency of movement”
Gregory Sutton
, Professor at Royal Society University, Department of Life Sciences, College of Science, University of Lincoln, U.K.

While biological systems generate legged locomotion in very different ways, there are two parameters, limb size and leg swing frequency, which can be used to determine the control strategy necessary to generate locomotion. We show that the fundamental physics of legged locomotion can be derived from these two parameters, and that these two parameters can then determine the fundamental control strategy necessary to generate stable locomotion. Consequently, while animals generate locomotion very differently, the fundamental physics of the movement can yield universal parameters for all legged locomotion.

“The importance of internal joint mechanics for understanding neural coordination strategies.”
Matthew Tresch
, Professor, Biomedical Engineering, Neuroscience, Physical Medicine and Rehabilitation, Northwestern University

Studies of motor control usually examine how the CNS activates muscles to achieve task performance – grasping an object or walking to a target. However, to achieve task performance, muscles must act through joints and so different control strategies, each achieving the same task performance, might result in aberrant stresses and strains within our joints. We show how consideration of these internal joint stresses and strains leads to better understanding of neural control strategies and might help guide investigations into neural circuitry underlying movement.

“Algorithmic Parameter Estimation and Uncertainty Quantification for Hodgkin–Huxley Neuron Models”.
Matthieu Chardon
, Research Assistant Prof, Dept of Neuroscience, Northwestern University

Neuromechanical models often rely on Hodgkin-Huxley (H-H) formulations for their neuron models. A challenge with H-H models is that many different sets of ion channel conductances can produce the same response from the model. This makes computational approaches for inferring ion channel parameters from observations of voltage data difficult or intractable. We show that by framing the inference in a Bayesian setting, which naturally allows multiple solutions, and employing a specific algorithm from the Markov chain Monte Carlo family allows us to successfully reconstruct “landscapes” or “maps” of possible parameter sets. The visualization of these solution maps (i.e., posteriors) enables physiologists to inspect and reason about the vast possibilities, sensitivities, and uncertainties of ion channel parameters. We will cover how this algorithm is being used to reverse engineer a locomotion circuit.

“Task-specificity in the Control of Insect Walking”.
Ansgar Büschges
, Department of Animal Physiology, Institute of Zoology, University of Cologne

Recent methodological advances in high-resolution-high-speed video analysis of locomotor behavior combined with new neurogenetic tools allow for studying the neural control of six-legged insect walking from the systems level, i.e., interleg coordination, to the single-leg level and to the level of single neuron function in generating a stepping cycle. The talk will report recent advances in unravelling the neural basis of six-legged walking with a specific focus on the generation of task-specific modifications.

“Comprehensive Study of Leg Strain Sensors”.
Gesa Dinges, Department of Mechanical and Aerospace Engineering, West Virginia University, US

Using interdisciplinary approaches, we characterized Drosophila leg campaniform sensilla morphologically and biomechanically. Further, we monitored single and group sensor effects on motor output during optogenetic manipulation. Our work highlights interindividual and interleg differences, how individual sensor morphology within a field can affect strain dynamics, and that optogenetic manipulation effects both intra- and interleg coordination. 

See the Workshop Time schedule HERE!