Neuronal control of locomotion in the lobster,Homarus americanus

Ayers, Joseph; Davis, William J.

doi:10.1007/bf00667782

Cited by 158 publications

(75 citation statements)

References 36 publications

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“…Test of this hypothesis requires stimulation of walking commands in a deafferented preparation, an experiment that has yet to be performed. The role of walking commands can be inferred indirectly (Ayers & Davis 1977b). The most parsimonious model relies on a network of four interneurons to generate the four basic synergies forming the step cycle (figures 3k and 4a).…”

Section: Biomimetic Robot Controllersmentioning

confidence: 99%

“…This connectivity is capable of explaining both the rapid changes in walking direction seen in behaving specimens as well as diagonal walking, where both the ThC and MC joints participate in the generation of propulsive forces (Ayers 2002a). Here, inter-joint reflexes serve to reinforce multi-joint synergies (Ayers & Davis 1977a, 1978. A further enigma of the walking system is that 'passive traction' is necessary for expression of command neuron evoked walking (Bowerman & Larimer 1974b).…”

Section: Biomimetic Robot Controllersmentioning

confidence: 99%

“…This control model differs from the predominate control model for insects that relies on independent oscillators for the three analogous joints (Buschges 2005). The insect model relies on segmental reflexes to mediate inter-joint coordination and although such reflexes are present in lobsters (Ayers & Davis 1977a), they only respond to leg movements and not positions and therefore appear to play a role in reinforcing coupling (Ayers & Davis 1978) rather than mediating coupling which must be flexible to permit walking in different directions. The primary requirements for the controller are that it generates a reasonable replica of the lobster motor programs, has the hooks necessary to mediate the adaptational capabilities of the animal model and operates in real time using relatively low-power microcontrollers.…”

Section: Biomimetic Robot Controllersmentioning

confidence: 99%

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Biomimetic approaches to the control of underwater walking machines

Ayers

Witting

2006

Phil. Trans. R. Soc. A.

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We have developed a biomimetic robot based on the American lobster. The robot is designed to achieve the performance advantages of the animal model by adopting biomechanical features and neurobiological control principles. Three types of controllers are described. The first is a state machine based on the connectivity and dynamics of the lobster central pattern generator (CPG). The state machine controls myomorphic actuators based on shape memory alloys (SMAs) and responds to environmental perturbation through sensors that employ a labelled-line code. The controller supports a library of action patterns and exteroceptive reflexes to mediate tactile navigation, obstacle negotiation and adaptation to surge. We are extending this controller to neuronal network-based models. A second type of leg CPG is based on synaptic networks of electronic neurons and has been adapted to control the SMA actuated leg. A brain is being developed using layered reflexes based on discrete time map-based neurons.

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Section: Biomimetic Robot Controllersmentioning

confidence: 99%

Section: Biomimetic Robot Controllersmentioning

confidence: 99%

Section: Biomimetic Robot Controllersmentioning

confidence: 99%

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Biomimetic approaches to the control of underwater walking machines

Ayers

Witting

2006

Phil. Trans. R. Soc. A.

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“…Lobsters and crabs move easily either forward/backward or laterally (Clarac 1981(Clarac , 1984Evoy and Ayers, 1982;Chasserat and Clarac, 1983). During forward walking by the lobster, the mero-carpopodite joint remains at a fixed angle (Macmillan, 1975;Evoy and Ayers, 1982;Mitchell and DeMont, 2003b), while during lateral walking by crustaceans this joint undergoes large angles of excursion (Ayers and Davis, 1977;Sleinis and Silvey, 1980;Jamon and Clarac, 1997). This movement of the limb about the joint generates different forces on the two sides of the laterally walking animal, with the trailing side pushing and the leading side decelerating the body (Blickhan and Full, 1987) or generating a pulling force (Sleinis and Silvey, 1980).…”

Section: Introductionmentioning

confidence: 99%

“…Lobsters and crabs have pinnated muscle architecture in their walking legs with the extension of the leg being powered by a single extensor muscle and the flexor by two muscles -a main and a very small accessory flexor (Macmillan and Dando, 1972;Macmillan, 1975;Ayers and Davis, 1977;Ayers and Clarac, 1978). According to a model presented by Alexander (1969Alexander ( , 1983) the force generated by a pinnate muscle system may be estimated from knowledge of the physiological cross-section of the muscle, the pinnation angle of the muscle fibres and the stress (force per unit area) exerted by the muscle.…”

Section: Introductionmentioning

confidence: 99%

Modelling torque generation by the mero-carpopodite joint of the american lobster and the snow crab

Mitchell¹,

DeMont²

2004

Marine and Freshwater Behaviour and Physiology

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The torque generated by a rotating joint comprises the useful force exerted by the joint on the external environment, and both the magnitude and distribution of torque through the step cycle during walking are important variables in understanding the mechanics of walking. The mechanics of the American lobster (Homarus americanus) and snow crab (Chionoecetes opilio) during walking were modelled to examine the relative roles of flexor versus extensor apodeme-muscle complexes, investigate which legs of these decapods likely contribute the greatest to locomotion, determine scaling effects of torque generation, and assess the relative roles of various model variables on torque production. Force generated along the length of the apodeme by the muscle was modelled based on apodeme surface area, muscle stress, and muscle fibre pinnation angle. Torque was then calculated from this estimated force and the corresponding moment arm. The flexor apodeme-muscle complex is calculated to generate consistently greater forces than the extensor, and generally this results in flexor torque being larger than extensor, though the snow crab does illustrate the opposite in two of its legs. This greater torque generation in flexion suggests that, in addition to the pushing of the trailing legs, the pulling action of the leading legs may play a significant role, at least during lateral walking. Leg 4 of both species appears to generate greater torques and thus provide the greatest forces for locomotion. Torque generation as a function of body size shows a second order response due to the increase in apodeme surface area. The pinnation angle of the muscle fibre is found to be insignificant in force generation, apodeme surface area (representing muscle cross sectional area) likely plays the most influential role in total force production, and moment arm controls the distribution of this force through the step cycle. Muscle stress remain a largely unknown quantity however, and may significantly affect both magnitude and distribution through step cycle of forces, and thus torque. Despite the uncertainty associated with the muscle stress parameter, the modelled results fit well with previously published force measurements.

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Central neuronal projections and neuromuscular organization of the basal region of the shore crab leg

Bévengut

Simmers

Clarac

1983

J of Comparative Neurology

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The musculature and associated skeleton, peripheral nervous system, and central projections of motor and sensory neurones of the two basal (thoracic and coxal) segments of the shore crab leg (fifth pereiopod, P5) were examined in vivo and with methylene blue or cobalt staining. Each of the four main basal muscles, promotor/remotor, levator/depressor, controlling the thoracico-coxal (T-C) and coxo-basal (C-B) limb joints, respectively, comprises several more or less discrete fibre bundles (total 14), with little morphological segregation of different functional groups. The innervation to the basal leg region is carried in two nerve roots arising from the thoracic ganglion. The anterior Th-Cx root carries both sensory and motor axons, while the posterior Th-Cx root is purely motor. Three previously undescribed sensory branches (two "epidermal" nerves and an "accessory" branch), in addition to that innervating the coxobasal chordotonal receptor, have been found in the distal part of the anterior Th-Cx root. Two clusters of 10 to 15 multipolar somata (diam. 30-125 micron) are located proximally at the bifurcation of the accessory nerve and distally where the latter enters the basipodite. The cell bodies (diameter 20-80 micron) of basal leg motoneurones (total ca. 30) lie in the dorsal cortex of the ganglion, with somata of functionally related motoneurones tending to form discrete structural groups. The morphology of individual motoneurones conforms to the general arthropod pattern. All are confined to the ipsilateral hemiganglion and their main neuropilar processes run parallel and in close apposition to each other with overlapping dendritic structures. Sensory projections arising from the CB chordotonal organ also ramify in the region of the neuropile invaded by motoneurones. The possible physiological significance of such structural associations within the CNS is discussed, as are the functional implications of basal limb anatomy in general.

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Neuronal control of locomotion in the lobster,Homarus americanus

Cited by 158 publications

References 36 publications

Biomimetic approaches to the control of underwater walking machines

Biomimetic approaches to the control of underwater walking machines

Modelling torque generation by the mero-carpopodite joint of the american lobster and the snow crab

Central neuronal projections and neuromuscular organization of the basal region of the shore crab leg

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