scholarly journals Locomotor patterns in freely moving crayfish (Procambarus clarkii)

1995 ◽  
Vol 198 (3) ◽  
pp. 683-700 ◽  
Author(s):  
M Jamon ◽  
F Clarac
Keyword(s):  
Stride Length ◽  
Procambarus Clarkii ◽  
Power Stroke ◽  
Coordination Pattern ◽  
Step Cycle ◽  
Return Stroke ◽  
Straight Line ◽  
Leg Coordination ◽  
Freely Moving ◽  
Locomotor Patterns

Freely walking crayfish, Procambarus clarkii, were studied using a video analysis procedure adapted especially for use with crayfish. The animals were placed in a tank and their homing behaviour was filmed as they returned in a straight line to their shelter. Various sequences were studied at the two following levels. First, the trajectory of each pair of legs (from leg 2 to leg 5) during the step cycle (power stroke and return stroke) was studied to measure stride length and to analyse in detail changes in acceleration. Each leg was found to contribute in a specific manner to locomotion. Second, ipsi- and contralateral leg coordination was investigated. Ipsilateral coordination was found to involve a metachronal organization from front to back in all the walking sequences recorded, whereas contralateral coordination involved, in addition to the weak alternate coupling commonly observed in treadmill walking, another coordination pattern where the legs on each side (legs 3 and 4) are in phase. The results obtained in these free-walking sequences are discussed and compared with those obtained previously, in particular in treadmill situations.

The relationship between leg stepping pattern and yaw torque oscillations in curve walking of two crayfish species

1999 ◽  
Vol 202 (22) ◽  
pp. 3069-3080 ◽  
Author(s):  
P. Domenici ◽  
J. Schmitz ◽  
M. Jamon
Keyword(s):  
Procambarus Clarkii ◽  
Open Loop ◽  
Power Stroke ◽  
Main Body ◽  
Astacus Leptodactylus ◽  
Stepping Pattern ◽  
Leg Coordination ◽  
Torque Curve ◽  
The Relationship ◽  
Step Amplitude

Curve walking in two species of crayfish, Procambarus clarkii and Astacus leptodactylus, was investigated to test whether the mechanism underlying curve walking is the synchronous action of a centrally pre-programmed leg tripod or whether it is the action of one principal leg that produces the main body yaw torque. Curve walking was induced by an optomotor visual stimulus, and the yaw torque produced by the tethered animals was measured in open-loop conditions. Our main results suggest that the yaw torque oscillations in both P. clarkii and A. leptodactylus are related to the movement of outer leg 4 (i.e. leg 4 on the outside of the turn). That is, the peaks in the yaw torque occur, on average, in synchrony with the power stroke of outer leg 4. When comparing the results of this open-loop experiment on P. clarkii with results previously obtained for curve walking in untethered individuals of the same species, we found a much higher variability in leg coordination in the open-loop situation. Similarly, here we did not find the same level of synchrony in the tripod (formed by outer leg 4 and inner legs 2 and 5) observed during untethered free walking. Therefore, we suggest that tethered conditions may diminish the need for stability and thus allow outer leg 4 to produce a body rotation regardless of the leg stepping configuration. The characteristics of leg 4 are in line with its major role in turning. According to previous studies, legs 4 provide the largest force and the largest step amplitude during walking, and their force includes both a pulling and a pushing component which can facilitate the control of turning. Although it is apparent that outer leg 4 is not the only leg that can produce an inward yaw torque, its major role in modulating the yaw torque suggests that there may be a specific, centrally generated control of outer leg 4 during curve walking in crayfish.

scholarly journals Quantitative Analysis of Walking in a Decapod Crustacean, the Rock Lobster Jasus Lalandii: I. Comparative Study of Free and Driven Walking

1983 ◽  
Vol 107 (1) ◽  
pp. 189-217 ◽  
Author(s):  
F. CLARAC ◽  
C. CHASSERAT
Keyword(s):  
Decapod Crustacean ◽  
Power Stroke ◽  
Rock Lobster ◽  
Return Stroke ◽  
Single Motor Unit ◽  
Mean Values ◽  
Walking Pattern ◽  
Leg Coordination ◽  
The Mean ◽  
The Relationship

The study compares the relative validity of the data obtained from two experimental situations, i.e. free walking and driven walking, in relation to leg coordination in Jasus lalandii (Milne-Edwards). The relationship between ipsilateral and contralateral legs during the forward as well as the backward walking sequences has been analysed in the two situations. They operate roughly in opposition. Although little difference in the mean phase values has been observed in the two experimental situations, the strength of coupling is greater in the driven walking animals. The power stroke (PS) duration correlates well with the period, but the return stroke (RS) is more variable and varies according to the leg considered. The phase does not appear to be correlated with the step period during free walking, but is correlated in the treadmill situation. Initially, several of the properties of the single motor unit discharges correlated with movement have identical mean values in both free and driven walking. However, several significant differences have been observed in the intra-burst organization. These differences indicate that the constraint of the treadmill decreases the variability of all parameters and produces a stable and more stereotyped walking pattern.

The Cuticular Stress Detector (CSD2) of the Crayfish: II. Activity During Walking and Influences on Leg Coordination

1986 ◽  
Vol 122 (1) ◽  
pp. 161-175
Author(s):  
DIEMUT KLÄRNER ◽  
JON P. BARNES
Keyword(s):  
Stance Phase ◽  
Sense Organ ◽  
Power Stroke ◽  
Initial Increase ◽  
Flexor Muscle ◽  
Step Cycle ◽  
Activity Peak ◽  
Leg Coordination ◽  
The One ◽  
Made In

1. When a crayfish walks forward, its legs are not loaded equally. The third pair is the one exerting the largest vertically directed force, and the fourth legs produce the major part of the propulsive force. 2. Chronic recordings from a CSD2 nerve were made in crayfish walking on a treadmill. The activity of CSD2 rises during the stance phase. The activity peak at the beginning of the power stroke is especially pronounced in leg 4, which was studied in detail. The average spike frequency of CSD2 recordings during the first part of the power stroke is positively correlated with the initial increase in force produced by the leg. This suggests that CSD2 responds especially well to rapid load changes. 3. When a wire was fixed around a fourth leg such that it depressed the patch of compliant cuticle associated with CSD2, the activity of the sense organ was elevated throughout the entire step cycle, and the time between leg 4 touching the ground and leg 3 lifting off was more variable than in normal walking. Thus, CSD2 seems to be involved in the coordination of the walking legs. 4. Depressing the compliant cuticle of CSD2 elicits reflexes in the flexor muscle and the anterior levator in tethered crayfish. Interleg reflexes were not found. Note:

scholarly journals Dactyl Sensory Influences on Rock Lobster Locomotion: I. Intrasegmental and Intersegmental leg Reflexes During Standing and Walking

1990 ◽  
Vol 148 (1) ◽  
pp. 89-112
Author(s):  
U. W. E. MÜLLER ◽  
FRANÇOIS CLARAC
Keyword(s):  
Sensory Nerve ◽  
Forward Direction ◽  
Power Stroke ◽  
Rock Lobster ◽  
Step Cycle ◽  
Return Stroke ◽  
Leg Muscles ◽  
Walking Pattern ◽  
Lift Off ◽  
Stimulation Of

1. Recordings of activity of the rock lobster dactyl sensory nerve during walking on a driven belt showed that the receptors of this nerve were mainly active during the power stroke when the leg was loaded. This nerve contains in particular the afferent fibres of the funnel canal organ (FCO) which are bimodal sensillae located in the cuticle of the dactylopodite of crustacean walking legs. 2. In the standing animal, brief electrical stimulation of the dactyl nerve had an influence on the proximal leg muscles of the stimulated leg. The promotor and levator muscles were excited and the remotor and depressor muscles were inhibited. 3. The opposite reaction was observed in adjacent ipsilateral legs in response to stimulation of a middle leg: the promotor and levator were inhibited and the remotor and depressor excited. 4. The resulting movement by the stimulated leg was stereotyped and always consisted of a lift-off from the substratum and a slight shift in the forward direction. The response in the adjacent legs was not powerful enough to elicit a movement. 5. In the walking animal the response of a single leg was dependent on the phase at which a stimulus arrived during the step cycle: during a power stroke (PS) this cycle was interrupted and a return stroke (RS) was initiated and continued. A stimulation at the normal switch from PS to RS had little effect, whereas a stimulation at late RS very often delayed the start of the following PS. Opposite reactions were given by the adjacent unstimulated legs: an RS was interrupted and a PS initiated or prolonged by the stimulus. 6. A comparison between ipsilateral walking legs showed the existence of some obvious differences: legs 4 and 5 were able to reset the walking pattern of all the legs, whereas the more anterior leg 3 returned to its old trajectory after stimulation and thus had no influence on the other legs.

Curve walking in freely moving crayfish (Procambarus clarkii)

1998 ◽  
Vol 201 (9) ◽  
pp. 1315-1329 ◽  
Author(s):  
P Domenici ◽  
M Jamon ◽  
F Clarac
Keyword(s):  
Procambarus Clarkii ◽  
Angular Acceleration ◽  
The Body ◽  
Body Axis ◽  
Power Stroke ◽  
Body Rotation ◽  
Freely Moving ◽  
Analysis System ◽  
Leg Kinematics ◽  
Phase Relationships

The curve walking of freely moving crayfish trained to walk along a curved path during homing behaviour was investigated using a video-analysis system. The leg kinematics and leg phase relationships, as well as the relationship between stepping patterns and body axis rotation measured relative to external references, were studied. <P> The anterior and posterior extreme positions of the power stroke (AEP and PEP, respectively) and step amplitudes were analysed. As in a previous study on crayfish curve walking on a treadmill, PEPs were more posterior in outer legs (the legs on the outside of the turn) than in the inner legs. As a result, outer legs showed larger step amplitudes than inner legs. Leg kinematics varied within each walking sequence. AEP leg angles (the angles between the body and leg axes at the AEP) tended to decrease over time for inner legs and increase for outer legs. This leg angle drift was present mainly in the anterior legs and it suggests that these legs did not completely compensate for the body rotation after each step. In addition, leg angle asymmetries in a direction opposite to that of leg angle drift were observed at the start of each curve-walking sequence, suggesting that the extensive training (3 weeks) may have allowed crayfish to anticipate the leg angle drift. <P> The rotational component of curve walking showed a discontinuous pattern, with the animal's body axis turning towards the inside of the curve only periodically. Analysis of cross-correlation functions showed that the angular acceleration of the body axis in the direction of the turn occurred during the power strokes of inner legs 2 and 5 and outer leg 4. While the tripod formed by these three legs showed in-phase relationships, the legs of the corresponding contralateral tripod (outer legs 2 and 5 and inner leg 4) were not in phase. We hypothesize that inner legs 2 and 5 and outer leg 4 act synergically causing the inward body rotation observed in curve-walking crayfish and that some of the asymmetries found in step geometry may be a passive phenomenon due to the body rotation.

Bimanual control strategies

2018 ◽  
Vol 72 (4) ◽  
pp. 966-978
Author(s):  
Chaoyi Wang ◽  
Charles H Shea
Keyword(s):  
Control Strategy ◽  
Bimanual Coordination ◽  
Control Strategies ◽  
Circular Path ◽  
Coordination Pattern ◽  
Bimanual Control ◽  
Straight Line ◽  
Index Of Difficulty ◽  
Line Path ◽  
Coordination Patterns

Two tasks (A and B) were designed which required participants to sequentially move through four target positions in a Lissajous display. Task A was designed so that participants could complete the task using either unimanual or bimanual control strategies. Task B was designed so that participants could complete the task using relatively simple or more complex bimanual control strategies. The purpose of this study was to determine which control strategy the participant utilises to complete the two tasks when Lissajous displays are provided and to determine the degree to which the size of the targets influences the control strategy chosen under these conditions. The movement amplitude between two adjacent targets and the target size resulted in an Index of Difficulty (ID) of 2 and 4 for each task. For both tasks, participants practised 15 trials (30 s per trial) for each ID and then was administered a test trial. The results for both Tasks A and B indicated that the ID2 condition resulted in a circular path, whereas the ID4 condition resulted in a straight-line path on the Lissajous plot. This suggests that at the low ID condition participants produced a continuous 1:1 with 90° phase offset bimanual coordination pattern. At the high ID condition, the participants consistently chose to switch to a more stable unimanual left and right movements in Task A and to transition between in-phase and anti-phase bimanual coordination patterns in Task B. In addition, both limbs’ movements were more harmonic in the low ID condition than in the high ID condition.

scholarly journals Quantitative Analysis of Walking in a Decapod Crustacean, the Rock Lobster Jasus Lalandii: II. Spatial and Temporal Regulation of Stepping in Driven Walking

1983 ◽  
Vol 107 (1) ◽  
pp. 219-243 ◽  
Author(s):  
C. CHASSERAT ◽  
F. CLARAC
Keyword(s):  
Narrow Range ◽  
Decapod Crustacean ◽  
Power Stroke ◽  
Careful Study ◽  
Rock Lobster ◽  
Return Stroke ◽  
Temporal Regulation ◽  
Belt Speed ◽  
Precise Adjustment ◽  
Wide Range

Spatial and temporal stepping parameters have been studied in a rocklobster walking on a treadmill moving at a wide range of speeds. The stride and the return stroke (RS) duration remain more or less stable and independent of the belt speed. Nevertheless, these ‘invariant’ parameters can act as spatial and temporal buffers resulting in a very precise adjustment of individual steps. A careful study of the power stroke (PS) duration demonstrates that the rock-lobster, although constrained to walk at an imposed belt speed, continues to correct its leg speed over a narrow range when the speed is considerably different from its natural one. Ipsilateral phases are always speed dependent, with an interleg ascending delay that is almost constant. The contralateral phase between legs of the same pair is approximately constant. Some of the parameters described are greatly influenced by gradual or abrupt variations in the belt speed. For a given speed, there is no absolute significance in the step period and ipsilateral phase. At very slow speeds, the interleg relations are significantly changed and have been studied separately. The metachrony observed at other speeds is discussed in relation to data from other arthropods.

scholarly journals STEPPING PATTERNS IN ANTS - INFLUENCE OF LOAD

1994 ◽  
Vol 192 (1) ◽  
pp. 119-127 ◽  
Author(s):  
C Zollikofer
Keyword(s):  
Stride Length ◽  
Food Source ◽  
Load Ratio ◽  
Stride Frequency ◽  
Coordination Pattern ◽  
Centre Of Mass ◽  
Food Items ◽  
Mass Load ◽  
Stepping Pattern ◽  
Tripod Gait

Stepping pattern geometry and walking kinematics of individual foragers of Cataglyphis fortis (Formicidae: Hymenoptera) were recorded during outward and homeward trips to and from a food source. While returning homewards, the animals were supplied with food items of defined mass (load ratio from 1.3 to 6.4) and volume. Under the influence of load, the temporal interleg coordination pattern was maintained (alternating tripod gait), but the spatial tripod pattern was modified. Tripod deformation was found to be proportional to the displacement of the centre of mass induced by the load. Stride length and stride frequency were not altered at any speed when animals carried loads compared with trips without a load. However, in order to maintain stability, mean stride length, mean speed and mean stride frequency were reduced while carrying loads.

Passive Properties of Swimmeret Motor Neurons

1997 ◽  
Vol 78 (1) ◽  
pp. 92-102 ◽  
Author(s):  
Carolyn M. Sherff ◽  
Brian Mulloney
Keyword(s):  
Motor Neurons ◽  
Continuous Production ◽  
Motor Pattern ◽  
Input Resistance ◽  
Membrane Potentials ◽  
Power Stroke ◽  
Return Stroke ◽  
Time Constants ◽  
Large Motor ◽  
Passive Electrical Properties

Sherff, Carolyn M. and Brian Mulloney. Passive properties of swimmeret motor neurons. J. Neurophysiol. 78: 92–102, 1997. Four different functional types of motor neurons innervate each swimmeret: return-stroke excitors (RSEs), power-stroke excitors (PSEs), return-stroke inhibitors (RSIs), and power-stroke inhibitors (PSIs). We studied the structures and passive electrical properties of these neurons, and tested the hypothesis that different types of motor neurons would have different passive properties that influenced generation of the swimmeret motor pattern. Cell bodies of neurons innervating one swimmeret were clustered in two anatomic groups in the same ganglion. The shapes of motor neurons in both groups were similar, despite the differences in locations of their cell bodies and in their functions. Diameters of their axons in the swimmeret nerve ranged from <2 to ∼35 μm. Resting membrane potentials, input resistances, and membrane time constants were recorded with microelectrodes in the processes of swimmeret motor neurons in isolated abdominal nerve cord preparations. Membrane potentials had a median of −59 mV, with 25th and 75th percentiles of −66.0 and −53 mV. The median input resistance was 6.4 MΩ, with 25th and 75th percentiles of 3.4 and 13.7 MΩ. Membrane time constants had a median of 9.3 ms, with 25th and 75th percentiles of 5.7 and 15.0 ms. Excitatory and inhibitory motor neurons had similar passive properties. RSE motor neurons were typically more depolarized than the other types, but the passive properties of RSE, PSE, RSI, and PSI neurons were not significantly different. Membrane time constants measured from cell bodies were briefer than those measured from neuropil processes, but membrane potentials and input resistances were not significantly different. The relative sizes of different motor neurons were measured from the sizes of their impulses recorded extracellularly from the swimmeret nerve. Smaller motor neurons had lower membrane potentials and were more likely to be active in the motor pattern than were large motor neurons. Motor neurons of different sizes had similar input resistances and membrane time constants. Motor neurons that were either oscillating or oscillating and firing in phase with the swimmeret motor pattern had lower average membrane potentials and longer time constants than those that were not oscillating. When the state of the swimmeret system changed from quiescence to continuous production of the motor pattern, the resting potentials, input resistances, and membrane time constants of individual swimmeret motor neurons changed only slightly. On average, both input resistance and membrane time constant increased. These similarities are considered in light of the functional task each motor neuron performs, and a hypothesis is developed that links the brief time constants of these neurons and graded synaptic transmission by premotor interneurons to control of the swimmeret muscles and the performance of the swimmeret system.

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