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.

scholarly journals Dactyl Sensory Influences on Rock Lobster Locomotion: II. ROLE IN INTERLEG COORDINATION

1990 ◽  
Vol 148 (1) ◽  
pp. 113-128 ◽  
Author(s):  
U. W. E. MÜLLER ◽  
FRANÇOIS CLARAC
Keyword(s):  
Electrical Stimulation ◽  
Sensory Nerve ◽  
Movement Pattern ◽  
Rock Lobster ◽  
Step Cycle ◽  
Extreme Position ◽  
Walking Pattern ◽  
Neuronal Connections ◽  
Phase Relationships ◽  
Stimulation Of

1. The effects of cyclic electrical stimulation of the dactyl sensory nerve (DN) on the walking pattern of rock lobsters were examined at the two crucial points within the step cycle: the anterior extreme position (AEP) and the posterior extreme position (PEP). 2. Stimulation during the occurrence of the PEP affected neither the movement pattern of the stimulated leg itself nor that of the ipsilateral adjacent legs. 3. Stimulation of the same intensity during the occurrence of the AEP interrupted the oscillation of the stimulated leg and affected the phase relationships of the ipsilateral adjacent legs. 4. The possibility that indirect influences were mediated by coupling to the substratum can be excluded. Neuronal connections may therefore exist between the funnel canal organs (FCO) of a single leg and the motor output of the adjacent legs. The discussion deals with whether the described channels alone are able to fulfil the requirements of a ‘coordinating mechanism’ as described in the literature.

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.

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.

Differential activation of octopaminergic (DUM) neurones via proprioceptors responding to flight muscle contractions in the locust

1999 ◽  
Vol 202 (24) ◽  
pp. 3555-3564
Author(s):  
O.T. Morris ◽  
C. Duch ◽  
P.A. Stevenson
Keyword(s):  
Sensory Feedback ◽  
Flight Muscle ◽  
Sensory Nerve ◽  
Direct Stimulation ◽  
Differential Activation ◽  
Leg Muscles ◽  
Flight Muscles ◽  
Stimulation Of Nerve ◽  
Dorsal Unpaired Median ◽  
Stimulation Of

The synaptic potentials generated in neuromodulatory octopaminergic dorsal unpaired median (DUM) neurones by afferents excited by twitch contractions of a dorso-ventral flight muscle were investigated in the locust. Responses to stimulation of the metathoracic wing elevator muscle 113 were obtained in locusts in which all sensory feedback from the thorax had been removed, except for feedback from the thoracic chordotonal organs, the axons of which enter via the purely sensory nerve 2. Afferents in nerve 2C, which originates from two chordotonal organs, responded reliably to twitch contractions of this flight muscle. Octopaminergic neurones innervating leg muscles (DUM5 neurones) received depolarising inputs and often spiked following stimulation of the muscle. In contrast, those innervating the wing muscles themselves (DUM3 and DUM3,4 neurones) received inhibitory inputs. The responses of DUM3,4,5 neurones, which project mainly to leg muscles, were more complex: most were excited by twitch contractions of M113 but some were inhibited. DUMDL, which innervates the dorsal longitudinal indirect flight muscles, showed no clear response. Direct stimulation of nerve 2C evoked depolarising inputs and spikes in DUM5 neurones and hyperpolarising inputs in DUM3 and DUM3,4 neurones. Our data suggest that sensory feedback from thoracic chordotonal organs, which are known to be activated rhythmically during flight, contributes to the differential activation of efferent DUM neurones observed during flight.

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.

Context-Dependent Modulation of Interlimb Cutaneous Reflexes in Arm Muscles as a Function of Stability Threat During Walking

2006 ◽  
Vol 96 (6) ◽  
pp. 3096-3103 ◽  
Author(s):  
Carlos Haridas ◽  
E. Paul Zehr ◽  
John E. Misiaszek
Keyword(s):  
Electrical Stimulation ◽  
Cutaneous Reflexes ◽  
Step Cycle ◽  
Functional Link ◽  
Leg Muscles ◽  
Postural Threat ◽  
Arm Muscles ◽  
The Right ◽  
Anterior Posterior ◽  
Stimulation Of

Cutaneous reflexes evoked in the muscles of the arms with electrical stimulation of nerves of the foot (“interlimb reflexes”) are observed during walking. These reflexes have been suggested to coordinate the actions of the legs and arms when walking is disturbed. Recently, we showed that cutaneous reflexes evoked in the leg muscles after stimulation at the foot are modulated according to the level of postural threat during walking. We hypothesized that the amplitude of interlimb cutaneous reflexes would similarly be modulated when subjects walk in unstable environments. Subjects walked on a treadmill under four walking conditions: 1) normal; 2) normal with unpredictable anterior–posterior (AP) perturbations; 3) arms crossed; and 4) arms crossed with unpredictable AP perturbations. Interlimb reflexes evoked from electrical stimulation of the right superficial peroneal or sural nerves were recorded bilaterally, at four points of the step cycle. These reflexes were compared between conditions in which the arms were moving in a similar manner: 1) normal versus AP walking and 2) arms crossed versus arms crossed with AP perturbations. Differences in reflex amplitudes between arms-crossed conditions were observed in most upper limb muscles when subjects were perturbed while walking compared with undisturbed walking. This effect was less apparent when the arms were swinging freely. The results indicate that the strength of interlimb connections is influenced by the level of postural threat (i.e., the context of the behavior), thereby suggesting that these reflexes serve a functional link between the legs and arms during locomotion.

Intra- and intersegmental pathways active during walking in the locust

1983 ◽  
Vol 218 (1212) ◽  
pp. 287-308 ◽  
Keyword(s):  
Pattern Generator ◽  
Short Latency ◽  
Chordotonal Organ ◽  
Campaniform Sensilla ◽  
Flexor Muscle ◽  
Walking Pattern ◽  
Excitatory Pathways ◽  
Motor Information ◽  
Antagonist Group ◽  
Stimulation Of

Electrical stimulation of femoral chordotonal organs, trochanteral campaniform sensilla, trochanteral hairplates and tibial muscles was used to reveal neuronal pathways active in the standing and walking locust. Responses evoked by campaniform sensilla stimulation were also recorded intracellularly from flexor motoneurons in fixed animals. The trochanteral campaniform sensilla have a direct short-latency connection to tibial extensor motoneurons and more labile, longer-latency, excitatory and inhibitory connections to the tibial flexors of the same leg. Trains of stimuli to the trochanteral campaniform sensilla initiated an early swing only if the stimulation was timed to occur during late stance. The importance of this type of load afference in step-timing was demonstrated by amputating the mesothoracic leg: the stump oscillated at a higher than normal frequency. Addition of a prosthetic leg restored normal stepping. Stimulation of the femoral chordotonal organ revealed short latency, excitatory pathways to both extensor and flexor motoneurons of the same leg. Trains of stimuli to the organ initiated early swing of this leg if applied late in stance. Stimulation of either the flexor or the extensor muscle evoked a response in the antagonist group of the same leg which was abolished by amputation distal to the muscles. The flexor-evoked response functioned only in the presence of load afference. The same was found for the pathway to the walking-pattern generator activated by stimulating the flexor muscle. Stimulation of the posterior trochanteral hairplates often evoked a swing but the latency could be several hundred milliseconds. Deafferentation showed that sensory input is critical for interganglionic coordination. There are labile polysynaptic excitatory and inhibitory pathways from the trochanteral campaniform senilla to the flexor motoneurons of the adjacent leg. Trains could evoke an early swing in the adjacent leg if time to occur during late stance and if the homonymous leg itself was not in late stance. Stimulation of the chordotonal organ revealedfast-conducting stable pathways to the flexors and extensors of all the ipsilateral legs. Trains could induce an early swing if timed late in the stance of the adjacent leg and if the homonymous leg itself was not in late stance. Amputation of the adjacent leg had no effect on the direct evoked responses but swing could not be evoked unless a prosthesis was added. Load afference is necessary for the effectiveness of the intersegmental chordotonal input to the walkingpattern generator. Stimulation of the trochanteral hairplate revealed no intersegmental pathway. The intra- and intersegmental pathways revealed by our experiments are summarized diagrammatically. The results suggest that an important function of load afference is to modulate the flow of proprioceptive and motor information within the walking-pattern generator.

Mechanics of Escape Responses in Crayfish (Orconectes Virilis)

1979 ◽  
Vol 79 (1) ◽  
pp. 245-263 ◽  
Author(s):  
P. W. WEBB
Keyword(s):  
Muscle Power ◽  
Total Duration ◽  
Power Stroke ◽  
Pressure Drag ◽  
Drag Forces ◽  
Added Water ◽  
Recovery Stroke ◽  
Low Efficiency ◽  
Lift Off ◽  
Tail Flip

Measurements of acceleration performance of crayfish (mean mass 0.018 kg) were made during lateral giant mediated tail flips (LG tail flips) and truncated tail flips at 15°C. The LG tail flip power stroke was composed of a lift-off phase, when crayfish accelerated vertically from the substrate, and a free swimming phase. The total duration of the power stroke was 44 ms, followed by a recovery stroke lasting 173 ms. Truncated tail flips were used in acceleration and swimming by crayfish free of the substrate. Power strokes had a mean duration of 36 ms, and recovery strokes 92 ms. Net velocities, acceleration rates, and distances travelled by the centre of mass were similar for both types of tail flips. Thrust was generated almost entirely by the uropods and telson. Velocities and angles of orientation to the horizontal of abdominal segments were similar for both types of tail flip. Angles of attack were large, varying from 30° to 90°. Pressure (drag) forces were considered negligible compared to inertial forces associated with the acceleration of added water mass. Thrust forces, energy and power were determined for exemplary tail flips. Thrust was 0.92 and 0.42 N for LG tail flip lift-off and swimming phases respectively, and 0.29 N for the swimming truncated tail flip. Rates of working were 0.39, 0.19, and 0.18 W respectively. The efficiency of converting muscle power to backward motion was estimated to be 0.5 for power strokes and 0.68 for complete swimming cycles. Comparisons with fish performance suggested fish would be less efficient (0.1-0.2). The low efficiency is attributed to energy lost in lateral recoil movements.

Rescue of motoneurons from the axotomized state by regeneration into a sensory nerve in cats

1991 ◽  
Vol 66 (5) ◽  
pp. 1462-1470 ◽  
Author(s):  
H. Nishimura ◽  
R. D. Johnson ◽  
J. B. Munson
Keyword(s):  
Electrical Stimulation ◽  
Electrical Properties ◽  
Sensory Nerve ◽  
Input Resistance ◽  
Cutaneous Nerve ◽  
Medial Gastrocnemius ◽  
Mechanical Activity ◽  
Muscle Nerve ◽  
Muscle Innervation ◽  
Stimulation Of

1. We studied the electrical properties of spinal motoneurons, the axons of which had regenerated into a cutaneous nerve. 2. In cats, all or part of the medial gastrocnemius (MG) muscle nerve was cut and directed distally into the caudal cutaneous sural (CCS) nerve, a sensory (primarily cutaneous) nerve. One or 2 yr later, electrical properties [conduction velocity (CV), rheobase (Irh), input resistance (RN), afterhyperpolarization (AHP), and excitatory postsynaptic potentials (EPSPs)] of MG motoneurons that had cross-regenerated into the CCS nerve were determined. These were compared with properties of normal and of axotomized MG motoneurons and with data from previous studies in which MG motoneurons had reinnervated their own or a foreign muscle. 3. Electrical stimulation of the MG-innervated CCS nerve produced no detected mechanical activity, indicating an absence of muscle innervation. Tactile stimulation of skin did not activate these motoneurons; i.e., they did not acquire properties of cutaneous afferents. 4. The CV and Irh of MG motoneurons axotomized 11 mo declined by 48 and 60%, respectively. 5. The CV of MG motoneurons that had regenerated through CCS was only slightly slower than normal, similar to that of MG motoneurons that reinnervated the “slow” muscle soleus (Foehring and Munson 1990). 6. The Irh and RN were also similar to those of MG motoneurons that had regenerated into the soleus muscle. 7. Electrical stimulation of the lateral gastrocnemius-soleus nerve generated EPSPs of normal or almost normal amplitude in MG motoneurons axotomized for 11 mo or cross-regenerated into CCS up to 2 yr.(ABSTRACT TRUNCATED AT 250 WORDS)

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