scholarly journals Behaviour and Motor Output for an Insect Walking on a Slippery Surface: II. Backward Walking

1985 ◽  
Vol 118 (1) ◽  
pp. 287-296 ◽  
Author(s):  
D. GRAHAM ◽  
S. EPSTEIN
Keyword(s):  
Motor Activity ◽  
Motor Pattern ◽  
Motor Output ◽  
Retractor Muscle ◽  
Backward Walking ◽  
Stick Insects ◽  
Weak Activity ◽  
Slippery Surface ◽  
Walking Recovery ◽  
Simple Phase

Coordination of the legs and the motor activity of four muscles in a middle leg were recorded in adult stick insects walking on a slippery glass surface. Backward walking was not achieved by a simple phase shift of levators and depressors. In all muscles examined, there was a considerable disturbance of motor activity during backward walking when compared with that found in forward walking. In backward walking, recovery was performed, in the middle leg, by strong fast unit activity in the retractor muscle and all muscles showed weak activity at inappropriate times. Fast motor output appeared to be superimposed on the forward walking motor pattern to produce the movements required for backward walking in this insect.

scholarly journals Behaviour and Motor Output of Stick Insects Walking on a Slippery Surface: I. Forward Walking

1983 ◽  
Vol 105 (1) ◽  
pp. 215-229 ◽  
Author(s):  
S. EPSTEIN ◽  
D. GRAHAM
Keyword(s):  
Glass Surface ◽  
Silicone Oil ◽  
Swing Phase ◽  
Motor Output ◽  
Mechanical Coupling ◽  
Stick Insects ◽  
Weak Activity ◽  
Slippery Surface ◽  
Coordination Patterns

The walking coordination and motor output of intact adult stick insects was examined when they were supported above an oiled glass surface. The viscosity of the silicone oil was adjusted so that the animal walked with either tripod or slow-walk coordination. In the absence of mechanical coupling through the substrate, the legs typically moved at different speeds in retraction. If these differences were not too large the walks were well-coordinated in the transitions from stance to swing phase. Motor output was variable and sometimes showed periods of very weak activity in depressors and retractors. Under these conditions an individual leg moved much more slowly than its neighbours, producing 2:1 coordination patterns.

Coupling of Efferent Neuromodulatory Neurons to Rhythmical Leg Motor Activity in the Locust

1998 ◽  
Vol 79 (1) ◽  
pp. 361-370 ◽  
Author(s):  
Sylvie Baudoux ◽  
Carsten Duch ◽  
Oliver T. Morris
Keyword(s):  
Motor Activity ◽  
Motor Neurons ◽  
Spike Activity ◽  
Motor Pattern ◽  
Rhythmic Activity ◽  
Motor Output ◽  
Variable Activity ◽  
Metathoracic Ganglion ◽  
Dum Neurons ◽  
Dorsal Unpaired Median

Baudoux, Sylvie, Carsten Duch, and Oliver T. Morris. Coupling of efferent neuromodulatory neurons to rhythmical leg motor activity in the locust. J. Neurophysiol. 79: 361–370, 1998. The spike activity of neuromodulatory dorsal unpaired median (DUM) neurons was analyzed during a pilocarpine-induced motor pattern in the locust. Paired intracellular recordings were made from these octopaminergic neurons during rhythmic activity in hindleg motor neurons evoked by applying pilocarpine to an isolated metathoracic ganglion. This motor pattern is characterized by two alternating phases: a levator phase, during which levator, flexor, and common inhibitor motor neurons spike, and a depressor phase, during which depressor and extensor motor neurons spike. Three different subpopulations of efferent DUM neurons could be distinguished during this rhythmical motor pattern according to their characteristic spike output. DUM 1 neurons, which in the intact animal do not innervate muscles involved in leg movements, showed no change apart from a general increase in spike frequency. DUM 3 and DUM 3,4 neurons produced the most variable activity but received frequent and sometimes pronounced hyperpolarizations that were often common to both recorded neurons. DUM 5 and DUM 3,4,5 neurons innervate muscles of the hindleg and showed rhythmical excitation leading to bursts of spikes during rhythmic activity of the motor neurons, which innervate these same muscles. Sometimes the motor output was coordinated across both sides of the ganglion so that there was alternating activity between levators of both sides. In these cases, the spikes of DUM 5 and DUM 3,4,5 neurons and the hyperpolarization of DUM 3 and DUM 3,4 neurons occurred at particular phases in the motor pattern. Our data demonstrate a central coupling of specific types of DUM neurons to a rhythmical motor pattern. Changes in the spike output of these particular efferent DUM neurons parallel changes in the motor output. The spike activity of DUM neurons thus may be controlled by the same circuits that determine the action of the motor neurons. Functional implications for real walking are discussed.

scholarly journals Influence of Coxa-Thorax Joint Receptors on Retractor Motor Output During Walking in Carausius Morosus

1985 ◽  
Vol 114 (1) ◽  
pp. 131-139
Author(s):  
D. Graham
Keyword(s):  
Motor Activity ◽  
Stick Insect ◽  
Motor Output ◽  
Power Stroke ◽  
Retractor Muscle ◽  
Relative Timing ◽  
Forward Movement ◽  
Carausius Morosus ◽  
Joint Receptors ◽  
Weak Resistance

The coxal leg-stump of a stick insect was rotated about the coxa-thorax joint, by means of a pen-motor, while the animal walked on a self-propelled double treadwheel. Motor activity in the retractor muscles of the legs was recorded for standing and walking animals with the stump of either the middle or hind leg moved forward and backward in a trajectory similar to that used in a walking step. In a standing animal the movement of either leg evokes a weak resistance reflex. If the animal walks with the middle leg-stump held still, then short and weak motor bursts are generated with the periodicity of the walking legs. Front and hind legs alternate in a manner typical of the middle leg amputee and the retractor muscle of the amputated leg is most active during the power stroke of the leg behind. When a middle leg-stump is moved at a different frequency from that of the walking legs, the motor output to the retractor is strongly modulated and depends on the relative timing of the stump and the walking legs. Rearward movement of the hind leg-stump, during walking, is always accompanied by strong motor output in the retractor muscle. In addition, forward movement in this leg-stump produces a resistance reflex similar to that produced in the standing animal.

Electrical activation of the pocket scratch central pattern generator in the turtle

1988 ◽  
Vol 60 (6) ◽  
pp. 2122-2137 ◽  
Author(s):  
S. N. Currie ◽  
P. S. Stein
Keyword(s):  
Receptive Field ◽  
Motor Activity ◽  
Central Pattern Generator ◽  
Motor Response ◽  
Tactile Stimulation ◽  
Motor Pattern ◽  
Pattern Generator ◽  
Motor Output ◽  
Stimulus Pulse ◽  
Stimulation Of

1. A low-spinal, immobilized turtle displays a fictive scratch reflex in hindlimb motor neurons in response to tactile stimulation of the shell (17, 19). Turtles exhibit three forms of the scratch reflex: rostral, pocket, and caudal. Each form is elicited by tactile stimulation of a different receptive field on the body surface. The ventral-posterior pocket (VPP) cutaneous nerve innervates the ventral-posterior portion of the pocket scratch receptive field (Fig. 1). Natural stimulation within the VPP nerve's receptive field evoked a pocket scratch reflex (Fig. 2A). Electrical stimulation of this nerve elicited robust pocket scratch reflexes (Fig. 2, B and C). 2. A single electrical pulse to the VPP nerve delivered at a voltage (greater than 5 V, 0.1 ms) that activated all the axons in the nerve was termed a "maximal" pulse. A single maximal pulse did not evoke a scratch motor response. It raised the excitability of the pocket scratch central pattern generator for several seconds, however. We revealed such excitability changes by applying maximal pulses to the VPP nerve at multisecond intervals (Figs. 5 and 6). When we delivered maximal pulses with interpulse intervals of less than or equal to 5 s, the first pulse produced no motor response and the second pulse evoked one or more cycles of pocket scratch. 3. A stimulus pulse applied to the VPP nerve was used as a probe for studying changes in the excitability of the pocket scratch CPG following scratch motor patterns. In a rested preparation, the stimulus pulse did not activate motor output. In contrast, the stimulus pulse evoked one or two cycles of pocket scratch activity if delivered within 2.5 s after the cessation of rhythmic pocket scratch motor activity (Figs. 7-9). These results are consistent with the hypothesis that the pocket scratch CPG has elevated excitability for seconds following the cessation of pocket scratch motor output. A single pulse applied to the VPP nerve evoked no response if delivered after the cessation of rostral scratch motor activity, however (Fig. 9D). 4. We used a train of maximal pulses to the VPP nerve to probe the form-specificity of the changes in the excitability following a rostral scratch motor pattern (Fig. 10). We set the stimulus parameters so that the train evoked one or two cycles of a pocket scratch motor pattern in a preparation that had rested for over 1 min.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Motor Patterns During Walking on a Slippery Walkway

2010 ◽  
Vol 103 (2) ◽  
pp. 746-760 ◽  
Author(s):  
Germana Cappellini ◽  
Yuri P. Ivanenko ◽  
Nadia Dominici ◽  
Richard E. Poppele ◽  
Francesco Lacquaniti
Keyword(s):  
Motor Output ◽  
Emg Activity ◽  
Head Orientation ◽  
Cycle Duration ◽  
Horizontal Shear ◽  
Motor Patterns ◽  
Spatiotemporal Organization ◽  
Surface Conditions ◽  
Gait Kinematics ◽  
Slippery Surface

Friction and gravity represent two basic physical constraints of terrestrial locomotion that affect both motor patterns and the biomechanics of bipedal gait. To provide insights into the spatiotemporal organization of the motor output in connection with ground contact forces, we studied adaptation of human gait to steady low-friction conditions. Subjects walked along a slippery walkway (7 m long; friction coefficient ≃ 0.06) or a normal, nonslippery floor at a natural speed. We recorded gait kinematics, ground reaction forces, and bilateral electromyographic (EMG) activity of 16 leg and trunk muscles and we mapped the recorded EMG patterns onto the spinal cord in approximate rostrocaudal locations of the motoneuron (MN) pools to characterize the spatiotemporal organization of the motor output. The results revealed several idiosyncratic features of walking on the slippery surface. The step length, cycle duration, and horizontal shear forces were significantly smaller, the head orientation tended to be stabilized in space, whereas arm movements, trunk rotations, and lateral trunk inclinations considerably increased and foot motion and gait kinematics resembled those of a nonplantigrade gait. Furthermore, walking on the slippery surface required stabilization of the hip and of the center-of-body mass in the frontal plane, which significantly improved with practice. Motor patterns were characterized by an enhanced (roughly twofold) level of MN activity, substantial decoupling of anatomical synergists, and the absence of systematic displacements of the center of MN activity in the lumbosacral enlargement. Overall, the results show that when subjects are confronted with unsteady surface conditions, like the slippery floor, they adopt a gait mode that tends to keep the COM centered over the supporting limbs and to increase limb stiffness. We suggest that this behavior may represent a distinct gait mode that is particularly suited to uncertain surface conditions in general.

Temperature Dependence of the Neural Control of the Moth Flight System

1970 ◽  
Vol 53 (3) ◽  
pp. 629-639
Author(s):  
JAMES L. HANEGAN ◽  
JAMES EDWARD HEATH
Keyword(s):  
Temperature Dependence ◽  
Neural Control ◽  
Motor Pattern ◽  
Motor Output ◽  
Flight Pattern ◽  
Flight System ◽  
Warm Up ◽  
Thoracic Ganglia ◽  
Flight Motor

1. The transition from the warm-up motor pattern to the flight motor pattern in the saturnid moth H. cecropia, is described. 2. The transition from warm-up to flight was found to be dependent on the temperature of the thoracic ganglia. 3. A model to account for the two different motor output patterns and the transition of the warm-up pattern to the flight pattern is proposed.

Intersegmental Coordination of Walking Movements in Stick Insects

2005 ◽  
Vol 93 (3) ◽  
pp. 1255-1265 ◽  
Author(s):  
Björn Ch. Ludwar ◽  
Marie L. Göritz ◽  
Joachim Schmidt
Keyword(s):  
Motor Pattern ◽  
Central Pattern Generators ◽  
Stick Insect ◽  
Neural Mechanisms ◽  
Chordotonal Organ ◽  
Adjacent Segment ◽  
Body Segments ◽  
Stick Insects ◽  
Pattern Generators ◽  
Leg Movements

Locomotion requires the coordination of movements across body segments, which in walking animals is expressed as gaits. We studied the underlying neural mechanisms of this coordination in a semi-intact walking preparation of the stick insect Carausius morosus. During walking of a single front leg on a treadmill, leg motoneuron (MN) activity tonically increased and became rhythmically modulated in the ipsilateral deafferented and deefferented mesothoracic (middle leg) ganglion. The pattern of modulation was correlated with the front leg cycle and specific for a given MN pool, although it was not consistent with functional leg movements for all MN pools. In an isolated preparation of a pair of ganglia, where one ganglion was made rhythmically active by application of pilocarpine, we found no evidence for coupling between segmental central pattern generators (CPGs) that could account for the modulation of MN activity observed in the semi-intact walking preparation. However, a third preparation provided evidence that signals from the front leg's femoral chordotonal organ (fCO) influenced activity of ipsilateral MNs in the adjacent mesothoracic ganglion. These intersegmental signals could be partially responsible for the observed MN activity modulation during front leg walking. While afferent signals from a single walking front leg modulate the activity of MNs in the adjacent segment, additional afferent signals, local or from contralateral or posterior legs, might be necessary to produce the functional motor pattern observed in freely walking animals.

The central nervous origin of the swimming motor pattern in embryos of Xenopus laevis

1982 ◽  
Vol 99 (1) ◽  
pp. 185-196 ◽  
Author(s):  
J. A. Kahn ◽  
A. Roberts
Keyword(s):  
Motor Activity ◽  
Similar Pattern ◽  
Sensory Feedback ◽  
Motor Nerve ◽  
Motor Pattern ◽  
Cycle Period ◽  
Phase Lag ◽  
Nerve Activity ◽  
Rhythmic Motor ◽  
Swimming Pattern

Rhythmic motor nerve activity was recorded in stage 37/38 Xenopus embryos paralysed with curare. The activity was similar to the swimming motor pattern in the following ways: cycle period (40–125 ms), alternation of activity on either side of a segment, rostro-caudal phase lag. Episodes of rhythmic motor activity could be evoked by stimuli that evoke swimming and inhibited by stimuli that normally inhibit swimming. On this basis we conclude that the swimming motor pattern is generated by a central nervous mechanism and is not dependent on sensory feedback. In addition to the swimming pattern, another pattern of motor activity (‘synchrony’) was sometimes recorded in curarized embryos. In this, the rhythmic bursts on either side of a segment occurred in synchrony, and the rhythm period (20–50 ms) was half that in swimming. This was probably not an artifact of curarization as there were indications of a similar pattern in uncurarized embryos. Its function remains unclear.

Analysis and modeling of the multisegmental coordination of shortening behavior in the medicinal leech. I. Motor output pattern

1992 ◽  
Vol 68 (5) ◽  
pp. 1683-1692 ◽  
Author(s):  
G. Wittenberg ◽  
W. B. Kristan
Keyword(s):  
Motor Neurons ◽  
Longitudinal Muscle ◽  
Motor Pattern ◽  
Mechanical Stimulus ◽  
Medicinal Leech ◽  
Motor Output ◽  
Simultaneous Excitation ◽  
Ventral Longitudinal Muscle ◽  
Output Pattern ◽  
Simple Behavior

1. To understand how a multisegmental animal coordinates motor activity over more than one segment, we studied shortening behavior in the medicinal leech, in which several segments contract longitudinally in response to a moderately strong mechanical stimulus. 2. We first demonstrated that the neuronal activity responsible for shortening behavior occurred in semi-intact and isolated nerve cord preparations, and then characterized the responses of motor neurons in isolated preparations. The motor output during shortening was simultaneous excitation of motor neurons innervating dorsal longitudinal muscle and of motor neurons innervating ventral longitudinal muscle. 3. The stronger the stimulus, the more segments produced the shortening motor output, with the segments nearest the stimulus recruited first. 4. Although the shortening response was produced in several segments near the site of stimulation, it was never produced in the stimulated segment, where the local bending motor output pattern was produced. The motor pattern suggests that shortening, initially considered a very simple behavior, requires the involvement of at least few segmentally iterated interneurons.

Load Signals Assist the Generation of Movement-Dependent Reflex Reversal in the Femur–Tibia Joint of Stick Insects

2006 ◽  
Vol 96 (6) ◽  
pp. 3532-3537 ◽  
Author(s):  
Turgay Akay ◽  
Ansgar Büschges
Keyword(s):  
Time Course ◽  
Stick Insect ◽  
Motor Output ◽  
Chordotonal Organ ◽  
Frequency Of Occurrence ◽  
Stick Insects ◽  
Extensor Motoneuron ◽  
Motoneuron Activity ◽  
First Time ◽  
Stimulation Of

Reinforcement of movement is an important mechanism by which sensory feedback contributes to motor control for walking. We investigate how sensory signals from movement and load sensors interact in controlling the motor output of the stick insect femur–tibia (FT) joint. In stick insects, flexion signals from the femoral chordotonal organ (fCO) at the FT joint and load signals from the femoral campaniform sensilla (fCS) are known to individually reinforce stance-phase motor output of the FT joint by promoting flexor and inhibiting extensor motoneuron activity. We quantitatively compared the time course of inactivation in extensor tibiae motoneurons in response to selective stimulation of fCS and fCO. Stimulation of either sensor generates extensor activity in a qualitatively similar manner but with a significantly different time course and frequency of occurrence. Inactivation of extensor motoneurons arising from fCS stimulation was more reliable but more than threefold slower compared with the extensor inactivation in response to flexion signals from the fCO. In contrast, simultaneous stimulation of both sense organs produced inactivation in motoneurons with a time course typical for fCO stimulation alone, but with a frequency of occurrence characteristic for fCS stimulation. This increase in probability of occurrence was also accompanied by a delayed reactivation of the extensor motoneurons. Our results indicate for the first time that load signals from the leg affect the processing of movement-related feedback in controlling motor output.

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