title: Deciphering the role of a coleopteran steering muscle via free flight stimulation.
abstract: Testing hypotheses of neuromuscular function during locomotion ideally requires the ability to record cellular responses and to stimulate the cells being investigated to observe downstream behaviors [1]. The inability to stimulate in free flight has been a long-standing hurdle for insect flight studies. The miniaturization of computation and communication technologies has delivered ultra-small, radio-enabled neuromuscular recorders and stimulators for untethered insects [2-8]. Published stimulation targets include the areas in brain potentially responsible for pattern generation in locomotion [5], the nerve chord for abdominal flexion [9], antennal muscles [2, 10], and the flight muscles (or their excitatory junctions) [7, 11-13]. However, neither fine nor graded control of turning has been demonstrated in free flight, and responses to the stimulation vary widely [2, 5, 7, 9]. Technological limitations have precluded hypotheses of function validation requiring exogenous stimulation during flight. We investigated the role of a muscle involved in wing articulation during flight in a coleopteran. We set out to identify muscles whose stimulation produced a graded turning in free flight, a feat that would enable fine steering control not previously demonstrated. We anticipated that gradation might arise either as a function of the phase of muscle firing relative to the wing stroke (as in the classic fly b1 muscle [14, 15] or the dorsal longitudinal and ventral muscles of moth [16]), or due to regulated tonic control, in which phase-independent summation of twitch responses produces varying amounts of force delivered to the wing linkages [15, 17, 18].
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, 65 Nanyang Drive, Singapore 637460, Singapore. Electronic address: hirosato@ntu.edu.sg.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Sato
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, 65 Nanyang Drive, Singapore 637460, Singapore.
authors.forename: Tat Thang
authors.initials: TT
authors.lastname: Vo Doan
authors.affiliation: Department of Electrical Engineering and Computer Science, University of California, 646 Sutardja Dai Hall, Berkeley, CA 94720, USA.
authors.forename: Svetoslav
authors.initials: S
authors.lastname: Kolev
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University, 65 Nanyang Drive, Singapore 637460, Singapore.
authors.forename: Ngoc Anh
authors.initials: NA
authors.lastname: Huynh
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, 65 Nanyang Drive, Singapore 637460, Singapore.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Electrical Engineering and Computer Science, University of California, 646 Sutardja Dai Hall, Berkeley, CA 94720, USA.
authors.forename: Travis L
authors.initials: TL
authors.lastname: Massey
authors.affiliation: Department of Electrical Engineering and Computer Science, University of California, 646 Sutardja Dai Hall, Berkeley, CA 94720, USA; Eccles Institute of Neuroscience, The John Curtin School of Medical Research, ANU College of Medicine, Biology & Environment, The Australian National University, 131 Garran Road, Acton, ACT 2601, Australia.
authors.forename: Joshua
authors.initials: J
authors.lastname: van Kleef
authors.affiliation: Division of Neurosciences, City of Hope Medical Center, 1500 East Duarte Road, Duarte, CA 91010, USA.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ikeda
authors.affiliation: Department of Electrical Engineering and Computer Science, University of California, 646 Sutardja Dai Hall, Berkeley, CA 94720, USA.
authors.forename: Pieter
authors.initials: P
authors.lastname: Abbeel
authors.affiliation: Department of Electrical Engineering and Computer Science, University of California, 646 Sutardja Dai Hall, Berkeley, CA 94720, USA.
authors.forename: Michel M
authors.initials: MM
authors.lastname: Maharbiz
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001517:Coleoptera / Q000502:physiology*; D003198:Computer Simulation; D004558:Electric Stimulation; D005426:Flight, Animal / Q000502:physiology*; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000502:physiology*; D014921:Wings, Animal / Q000502:physiology