The Effect of Load on Locomotion in Crayfish

1981 ◽  
Vol 92 (1) ◽  
pp. 277-288 ◽  
Author(s):  
J. R. GROTE

Leg movements and leg muscle activity were monitored in unrestrained crayfish walking freely under several different load conditions. A variety of changes in the character of locomotion was found to vary with load including: (1) the timing and frequency of the step cycle and in particular the power stroke duration; (2) significant leg-positional changes which result in increased mechanical advantage under load; and (3) the (loadinduced) recruitment of the depressor muscle. In restrained, immobile animals, isometric loading of depression resulted in inhibition of motor activity in the depressor-remotor nerve, an effect similar to the vertebrate tendon reflex.

1987 ◽  
Vol 133 (1) ◽  
pp. 111-120 ◽  
Author(s):  
F. Delcomyn

1. Rhythmic motor activity may be recorded in the legs of cockroaches during the execution of several different types of behaviour that involve leg movements. It was examined in detail during searching and walking. 2. During walking, motor activity always consisted of a series of bursts separated by silent periods. During searching, it was usually continual, but modulated in frequency. 3. Sometimes, the motor pattern recorded from a searching leg was burst-like rather than modulated. In these cases, it could nevertheless be reliably distinguished from the motor pattern recorded during walking by a simple analysis of the burst pattern. 4. An analysis of the motor pattern recorded during righting indicated that this pattern was more like that for walking than that for searching. Therefore, searching is not simply walking that lacks certain periodic sensory input due to leg contact with the ground. 5. It is concluded that walking and searching can be reliably distinguished from one another on the basis of an analysis of a record of motor activity in a single leg muscle only. An ability to distinguish between similar types of behaviour on the basis of the motor pattern may prove useful in a variety of experiments.


2019 ◽  
Author(s):  
Friedrich Lersch ◽  
Pascal Jerney ◽  
Heiko Kaiser ◽  
Cédric Willi ◽  
Katharina Steck ◽  
...  

Motor activity during general anesthesia (GA) without curarization is often interpreted as reflecting insufficient analgosedation. Here we present the case of an octogenarian scheduled for deep sclerectomy receiving opioid-sparing electroencephalography-(EEG)-guided anesthesia. Periodic Leg Movements (PLM) made their appearance with ongoing surgery while his raw EEG displayed a pattern of deep GA (burst suppression). To the best of our knowledge, this is the first description of actimetry-documented persisting PLM during EEG-monitored GA. Recognizing PLM in the context of GA is of importance for anesthesiologists, as increasing sedation may increase motor activity.


SLEEP ◽  
2005 ◽  
Vol 28 (8) ◽  
pp. 998-1004 ◽  
Author(s):  
Raffaele Ferri ◽  
Marco Zucconi ◽  
Mauro Manconi ◽  
Oliviero Bruni ◽  
Silvia Miano ◽  
...  

1988 ◽  
Vol 6 (3) ◽  
pp. 229-237 ◽  
Author(s):  
J.P. Clarys ◽  
J. Cabri ◽  
R.J. Gregor

2020 ◽  
Vol 28 (6) ◽  
pp. 675-684 ◽  
Author(s):  
Shahul Mujib Kamal ◽  
Norazryana Binti Mat Dawi ◽  
Sue Sim ◽  
Rui Tee ◽  
Visvamba Nathan ◽  
...  

BACKGROUND: Walking is one of the important actions of the human body. For this purpose, the human brain communicates with leg muscles through the nervous system. Based on the walking path, leg muscles act differently. Therefore, there should be a relation between the activity of leg muscles and the path of movement. OBJECTIVE: In order to address this issue, we analyzed how leg muscle activity is related to the variations of the path of movement. METHOD: Since the electromyography (EMG) signal is a feature of muscle activity and the movement path has complex structures, we used entropy analysis in order to link their structures. The Shannon entropy of EMG signal and walking path are computed to relate their information content. RESULTS: Based on the obtained results, walking on a path with greater information content causes greater information content in the EMG signal which is supported by statistical analysis results. This allowed us to analyze the relation between muscle activity and walking path. CONCLUSION: The method of analysis employed in this research can be applied to investigate the relation between brain or heart reactions and walking path.


2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Aisha Islam ◽  
Lisa Alcock ◽  
Kianoush Nazarpour ◽  
Lynn Rochester ◽  
Annette Pantall

Abstract Gait deficits are a common feature of Parkinson’s disease (PD) and predictors of future motor and cognitive impairment. Understanding how muscle activity contributes to gait impairment and effects of therapeutic interventions on motor behaviour is crucial for identifying potential biomarkers and developing rehabilitation strategies. This article reviews sixteen studies that investigate the electromyographic (EMG) activity of lower limb muscles in people with PD during walking and reports on their quality. The weight of evidence establishing differences in motor activity between people with PD and healthy older adults (HOAs) is considered. Additionally, the effect of dopaminergic medication and deep brain stimulation (DBS) on modifying motor activity is assessed. Results indicated greater proximal and decreased distal activity of lower limb muscles during walking in individuals with PD compared to HOA. Dopaminergic medication was associated with increased distal lower limb muscle activity whereas subthalamic nucleus DBS increased activity of both proximal and distal lower limb muscles. Tibialis anterior was impacted most by the interventions. Quality of the studies was not strong, with a median score of 61%. Most studies investigated only distal muscles, involved small sample sizes, extracted limited EMG features and lacked rigorous signal processing. Few studies related changes in motor activity with functional gait measures. Understanding mechanisms underpinning gait impairment in PD is essential for development of personalised rehabilitative interventions. Recommendations for future studies include greater participant numbers, recording more functionally diverse muscles, applying multi-muscle analyses, and relating EMG to functional gait measures.


2005 ◽  
Vol 94 (5) ◽  
pp. 3143-3158 ◽  
Author(s):  
C. Grüneberg ◽  
J. Duysens ◽  
F. Honegger ◽  
J.H.J. Allum

This study was designed to provide evidence for the hypothesis that human balance corrections in response to pitch perturbations are controlled by muscle action mainly about the ankle and knee joints, whereas balance corrections for roll perturbations are controlled predominantly by motion about the hip and lumbro-sacral joints. A dual-axis rotating support surface delivered unexpected random perturbations to the stance of 19 healthy young adults through eight different directions in the pitch and the roll planes and three delays between pitch and roll directions. Roll delays with respect to pitch were no delay, a short 50-ms delay of roll with respect to pitch movements, (chosen to correspond to the onset time of leg muscle stretch reflexes), and a long 150-ms delay between roll and pitch movements (chosen to shift the time when trunk roll velocity peaks to the time when trunk peak pitch velocity normally occurs). Delays of stimulus roll with respect to pitch resulted in delayed roll responses of the legs, trunk, arms, and head consistent with stimulus delay without any changes in roll velocity amplitude. Delayed roll perturbations induced only small changes in the pitch motion of the legs and trunk; however, major changes were seen in the time when roll motion of the trunk was arrested. Amplitudes and directional sensitivity of short-latency (SL) stretch reflexes in ankle muscles were not altered with increasing roll delay. Small changes to balance correcting responses in ankle muscles were observed. SL stretch reflexes in hip and trunk muscles were delayed, and balance-correcting responses in trunk muscles became split into two distinct responses with delayed roll. The first of these responses was small and had a directional responsiveness aligned more along the pitch plane. The main, larger, response occurred with an onset and time-to-peak consistent with the delay in trunk roll displacement and its directional responsiveness was roll oriented. The sum of the amplitudes of these two types of balance-correcting responses remained constant with roll delay. These results support the hypothesis that corrections of the body's pitch and roll motion are programmed separately by neural command signals and provide insights into possible triggering mechanisms. The evidence that lower leg muscle balance-correcting activity is hardly changed by delayed trunk roll also indicates that lower leg muscle activity is not predominant in correcting roll motion of the body. Lower leg and trunk muscle activity appears to have a dual action in balance corrections. In trunk muscles the main action is to correct for roll perturbations and the lesser action may be an anticipatory stabilizing reaction for pitch perturbations. Likewise, the small changes in lower leg muscle activity may result from a generalized stabilizing reaction to roll perturbations, but the main action is to correct for pitch perturbations.


2005 ◽  
Vol 94 (1) ◽  
pp. 657-672 ◽  
Author(s):  
Frédéric Bretzner ◽  
Trevor Drew

We used microstimulation to examine the contribution of the motor cortex to the structure and timing of the hindlimb step cycle during locomotion in the intact cat. Stimulation was applied to the hindlimb representation of the motor cortex in 34 sites in three cats using either standard glass-insulated microelectrodes (16 sites in 1 cat) or chronically implanted microwire electrodes (18 sites in 2 cats). Stimulation at just suprathreshold intensities with the cat at rest produced multijoint movements at a majority of sites (21/34, 62%) but evoked responses restricted to a single joint, normally the ankle, at the other 13/34 (38%) sites. Stimulation during locomotion generally evoked larger responses than the same stimulation at rest and frequently activated additional muscles. Stimulation at all 34 sites evoked phase-dependent responses in which stimulation in swing produced transient increases in activity in flexor muscles while stimulation during stance produced transient decreases in activity in extensors. Stimulation with long (200 ms) trains of stimuli in swing produced an increased level of activity and duration of flexor muscles without producing changes in cycle duration. In contrast, stimulation during stance decreased the duration of the extensor muscle activity and initiated a new and premature period of swing, resetting the step cycle. Stimulation of the pyramidal tract in two of these three cats as well as in two additional ones produced similar effects. The results show that the motor cortex is capable of influencing hindlimb activity during locomotion in a similar manner to that seen for the forelimb.


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