Neural control of slow muscle mechanics during feeding in Aplysia californica

Abstract

Event Abstract Back to Event Neural control of slow muscle mechanics during feeding in Aplysia californica Gregory P. Sutton1, Jeffrey M. McManus2, Miranda J. Cullins3 and Hillel Chiel2, 3, 4 1 University of Bristol, Biology, United Kingdom 2 Case Western Reserve University, Biology, United States 3 Case Western Reserve University, Biomedical Engineering, United States 4 Case Western Reserve University, Neurosciences, United States Variability in the neural firing patterns that generate behaviour pose a difficult question: “How do changes in neural patterns reflect changes in output behaviours?” Often this question is addressed using purely statistical methods. We propose to address this question by applying a biomechanical approach, which can then direct subsequent statistical analyses. We demonstrate this principle using the feeding apparatus of the marine mollusc Aplysia californica. Aplysia’s feeding apparatus, the buccal mass, uses a muscular grasper, the odontophore, to move seaweed past the jaws and into the esophagus. As it does so, the buccal mass moves at a maximum velocity of 1 cm/s – so slowly that the inertial and damping forces are three orders of magnitude smaller than passive elastic and active muscle forces. System analysis can therefore be simplified by ignoring inertial and damping forces. The system is dominated by the position dependent elastic forces and the active forces generated by the muscles. Most importantly, motion of the odontophore is dominated by active forces in two muscles: protractor muscle I2 and jaw muscle I1/I3. Activation of the motor neurons of these two muscles generate forces whose balance moves the odontophore through a series of positions. We designate the predicted outcome of a pattern of motor neuron activity and the mechanical forces a neuromechanical equilibrium point. Analysis of neuromechanical equilibrium points predicts that the amount of motion of the odontophore towards the jaws will be correlated with the duration of I2 activity and with the amount of overlap between the I2 and I1/I3 activity. By measuring the neural activation times and odontophore motion from 37 feeding behaviours in a semi-intact preparation, we found that the correlations predicted by the biomechanical analysis were validated. Analyzing control of the buccal mass in terms of manipulation of neuromechanical equilibrium points provides concrete and testable predictions that, in this case, are verified by analysis of experimental data. Control by manipulation of equilibrium points is a direct consequence of any system in which inertial forces and viscous forces are orders of magnitude smaller than the elastic forces, and thus represents a framework for how any slow moving system could be controlled. Keywords: Aplysia, Biomechanics, Neural control Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for Participant Symposium) Topic: Motor Systems Citation: Sutton GP, McManus JM, Cullins MJ and Chiel H (2012). Neural control of slow muscle mechanics during feeding in Aplysia californica. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00245 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Apr 2012; Published Online: 07 Jul 2012. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Gregory P Sutton Jeffrey M McManus Miranda J Cullins Hillel Chiel Google Gregory P Sutton Jeffrey M McManus Miranda J Cullins Hillel Chiel Google Scholar Gregory P Sutton Jeffrey M McManus Miranda J Cullins Hillel Chiel PubMed Gregory P Sutton Jeffrey M McManus Miranda J Cullins Hillel Chiel Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.