Effects of Spontaneous Locomotion on the Cricket's Walking Response to a Wind Stimulus

Gras, Heribert; Bartels, Anke

doi:10.1007/s001140050608

Cited by 2 publications

(4 citation statements)

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“…Context-dependent reflex activity has been described in a number of arthropod species. It can be a result of selective activation of distinct motor patterns depending on which set of mechanoreceptors are stimulated (Siegler and Burrows, 1986), or due to gain modulation (Belanger et al, 2000), sign reversal (Bässler and Büschges, 1998), gating (Staudacher and Schildberger, 1998) or likelihood modulation (Gras and Bartels, 1998), depending on the current behavioural state.…”

Section: Introductionmentioning

confidence: 99%

Perturbation of leg protraction causes context-dependent modulation of inter-leg coordination, but not of avoidance reflexes

Ebeling

Dürr

2006

Journal of Experimental Biology

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The central requirement for legged locomotion is the simultaneous control of propulsion, clearance above ground and balance of the body frame. Apart from solving this multiple control problem, the neural controller needs to be adaptive in order to account for varying physical conditions of the environment, such as slope and compliance of the substrate, but also for changes in behavioural context of the animal. For example: whereas control of a light, running insect with low clearance may well entirely rely on centrally generated rhythms and inherent viscoelastic properties of the musculoskeletal system known as 'preflexes' (Jindrich and All animals capable of legged locomotion execute fast, adaptive compensatory movements in response to perturbation of a step cycle. In terms of motor control, such adaptive behaviour typically involves changes in the kinematics of the perturbed limb as well as changes in coordination between legs. Moreover, the unpredictable variety of real life situations implies that compensatory responses should be sensitive to the behavioural context of the animal. We have investigated the extent to which the compensatory response of a walking stick insect (Carausius morosus) adapts in parallel to strong contextdependent adaptation of step kinematics and inter-leg coordination. The behavioural contexts we chose were straight walking and visually induced curve walking, for both of which the steady state limb kinematics and interleg coupling strengths were known. In case of curve walking, we further distinguished contexts according to whether the inner or the outer leg was perturbed. The three contexts differed strongly with respect to the set of joint actions before perturbation. Upon mechanical perturbation of front leg protraction, we studied contextdependent differences in a local avoidance reflex of the perturbed leg, as well as in coordination mechanisms that couple the step cycles of the perturbed leg to its unperturbed neighbours.In all three walking contexts, obstacle contact caused an avoidance movement of the front leg that deviated from the unperturbed swing trajectory. Swing duration was increased while step distance was decreased; however, both effects vanished in the subsequent unperturbed step. The prevailing immediate reaction of the three leg joints were retraction of the coxa (>76%), levation of the femur (>80%), and flexion of the tibia (>80%), regardless of the behavioural context and, therefore, joint action prior to perturbation. Moreover, activation of each one of these joint actions was shown to be independent of the other two. Thus, local avoidance reflexes are not modulated by the descending visual information that causes transition from straight to curve walking, but are composed of context-independent joint actions.Perturbation of the front leg also caused significant shifts of the touch-down position of the perturbed leg and of its unperturbed neighbours. If the inner front leg was perturbed, this shift could persist until the subsequent step. Perturbation affected...

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Section: Introductionmentioning

confidence: 99%

Perturbation of leg protraction causes context-dependent modulation of inter-leg coordination, but not of avoidance reflexes

Ebeling

Dürr

2006

Journal of Experimental Biology

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“… 21 , 29 In addition, a previous study involving tethered crickets walking on a treadmill revealed that escape behavior probability increased as spontaneous walking velocity increased. 28 Using a closed-loop controlled servosphere treadmill system that provided quantitative stimulation to freely moving crickets, the current study revealed for the first time that when moving crickets were stimulated, they momentarily stopped and then exhibited either running or jumping as escape behavior. When the airflow velocity was slower than 0.54 m/s, most crickets stopped, but roughly half did not move after pausing.…”

Section: Discussionmentioning

confidence: 80%

“…In the escape response to the same stimulus velocity, the response probability was higher when the cricket was in motion than when it was stationary, corroborating a previous study. 28 This finding indicated that crickets were more sensitive to airflow stimuli when in motion. This result is consistent with some studies that animals’ sensory perception is enhanced while in motion.…”

Section: Discussionmentioning

confidence: 94%

“… 25 , 26 , 27 Another similar experiment demonstrated that the probability of the escape response to airflow increases with forward speed when crickets walking spontaneously are stimulated. 28 These findings suggest that cricket wind-elicited escape behavior, the motor parameter characteristics of which have been explicitly described, is a promising model to explore behavioral modulation by an animal’s motor state, but the experiments should be ideally conducted in unconstrained conditions with quantitatively manipulated stimulation.…”

Section: Introductionmentioning

confidence: 99%

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