Timing and shaping influences on the motor output for walking in stick insects

1987 ◽  
Vol 55 (6) ◽  
pp. 397-401 ◽  
Author(s):  
U. Bässler
Keyword(s):  
Motor Output ◽  
Stick Insects

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.

scholarly journals Insects are both Impeded and Propelled by their Legs During Walking

1983 ◽  
Vol 104 (1) ◽  
pp. 129-137 ◽  
Author(s):  
D. GRAHAM
Keyword(s):  
Motor Output ◽  
Force Platform ◽  
Insect Locomotion ◽  
Stick Insects ◽  
Kinetics Of

The kinetics of walking behaviour in stick insects differ from vertebrate walking behaviour. The differences suggest that insect locomotion consists of a hold-push-recover sequence similar to that used by a climber. This is supported by evidence from force platform measurements on free-walking insects and motor output recordings from animals walking on a treadwheel.

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.

Effects of Afference Sign Reversal on Motor Activity in Walking Stick Insects (Carausius Morosus)

1981 ◽  
Vol 91 (1) ◽  
pp. 179-193
Author(s):  
D. GRAHAM ◽  
U. BÄSSLER
Keyword(s):  
Sensory Input ◽  
Flexor Tendon ◽  
Sense Organ ◽  
Extensor Tendon ◽  
Motor Output ◽  
Chordotonal Organ ◽  
Internal Oscillation ◽  
Stick Insects ◽  
Peripheral Sensory ◽  
Walking Stick

The apodeme of the femoral chordotonal organ of a middle leg can be moved from its normal position close to the extensor tendon and inserted into a clot cut in the flexor tendon. This inverts the output of the sense organ and produces a ‘wrong’ afference. During walking on a pair of light wheels the operated leg either makes walking steps or is raised and extended in a ‘salute’ posture. The coordination is similar to that for an intact animal if the operated leg walks but changes to the middle leg amputee timing when the operated leg ‘salutes’. The transitions between saluting and the normal walking behaviour of the operated leg can be explained if it is assumed that the animal depends heavily upon the C.O. for determining the tibia position during both walking and the saluting behaviour. Motor output to the levators and depressors of the femur and the protractors and retractors of the coxa shows bursting activity during the salute at the frequency of 3–4 Hz. The depressor bursts are also modulated at a frequency of 1 Hz and produce strong regular depressions of the femur which are co-ordinated with the movements of the other legs. The maintenance of regular depressor contractions during the salute shows that an important part of the motor output to the saluting leg (depressor activity) arises from an internal oscillation or rhythmic command which maintains its co-ordinated activity when the normal peripheral sensory input to the leg it is attempting to operate is absent. Retractor activity wanes during the salute suggesting that propulsion is much more dependent upon peripheral input than is the support musculature (depressors), The creation of a ‘wrong’ afference can be used to map the importance of the operated organ in different sub-units of behaviour.

Behavior in the Brain

2010 ◽  
Vol 24 (2) ◽  
pp. 76-82 ◽  
Author(s):  
Martin M. Monti ◽  
Adrian M. Owen
Keyword(s):  
Motor Behavior ◽  
Functional Neuroimaging ◽  
Brain Activity ◽  
Motor Output ◽  
The Unconscious ◽  
Ethical Implications ◽  
Brain Responses ◽  
Minimally Conscious ◽  
Brain Insults ◽  
Brain Behavior

Recent evidence has suggested that functional neuroimaging may play a crucial role in assessing residual cognition and awareness in brain injury survivors. In particular, brain insults that compromise the patient’s ability to produce motor output may render standard clinical testing ineffective. Indeed, if patients were aware but unable to signal so via motor behavior, they would be impossible to distinguish, at the bedside, from vegetative patients. Considering the alarming rate with which minimally conscious patients are misdiagnosed as vegetative, and the severe medical, legal, and ethical implications of such decisions, novel tools are urgently required to complement current clinical-assessment protocols. Functional neuroimaging may be particularly suited to this aim by providing a window on brain function without requiring patients to produce any motor output. Specifically, the possibility of detecting signs of willful behavior by directly observing brain activity (i.e., “brain behavior”), rather than motoric output, allows this approach to reach beyond what is observable at the bedside with standard clinical assessments. In addition, several neuroimaging studies have already highlighted neuroimaging protocols that can distinguish automatic brain responses from willful brain activity, making it possible to employ willful brain activations as an index of awareness. Certainly, neuroimaging in patient populations faces some theoretical and experimental difficulties, but willful, task-dependent, brain activation may be the only way to discriminate the conscious, but immobile, patient from the unconscious one.

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