Regulation of Arm and Leg Movement during Human Locomotion

Zehr, E. Paul; Duysens, Jacques

doi:10.1177/1073858404264680

Cited by 349 publications

(279 citation statements)

References 148 publications

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“…A third possibility is that the two aspects of the task, namely the locomotion and the voluntary movement, would each have their own temporal activation components that are superimposed in the combined task, as envisioned by the motor primitives proposal. This result could be expected if the characteristic activation timing for locomotion were generated separately from any voluntary activation timing, although a coupling of corticospinal with cervical and thoraco-lumbar propriospinal circuits (Dietz, 2002;Zehr and Duysens, 2004) may result in partial synchronization of activation components. Additional temporal components would imply voluntary activation timings that are not represented in the locomotion sequence.…”

Section: Introductionmentioning

confidence: 91%

Coordination of Locomotion with Voluntary Movements in Humans

et al. 2005

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Muscle activity occurring during human locomotion can be accounted for by five basic temporal activation patterns in a variety of locomotion conditions. Here, we examined how these activation patterns interact with muscle activity required for a voluntary movement. Subjects produced a voluntary movement during locomotion, and we examined the resulting kinematics, kinetics, and EMG activity in 16 -31 ipsilateral limb and trunk muscles during the tasks. There were four voluntary tasks added to overground walking (ϳ5 km/h) in which subjects kicked a ball, stepped over an obstacle, or reached down and grasped an object on the floor (weight support on either the right or the left foot). Statistical analyses of EMG waveforms showed that the five basic locomotion patterns were invariantly present in each task, although they could be differently weighted across muscles, suggesting a characteristic locomotion timing of muscle activations. We also observed a separate activation that was timed to the voluntary task. The coordination of locomotion with the voluntary task was accomplished by combining activation timings that were associated separately with the voluntary task and locomotion. Activation associated with the voluntary tasks was either synchronous with the timing for locomotion or had additional activations not represented in the basic locomotion timing. We propose that this superposition of an invariant locomotion timing pattern with a voluntary activation timing may be consistent with the proposal suggesting that compound movements are produced through a superposition of motor programs.

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Section: Introductionmentioning

confidence: 91%

Coordination of Locomotion with Voluntary Movements in Humans

et al. 2005

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“…Centrally located neuronal circuits, known as central pattern generators (CPG), can generate the basic motor pattern for locomotion even without afferent feedback from peripheral receptors 21) . These descending commands of the central nervous system delegate the motor commands for rhythmic movement of the CPG network in the spinal cord 23,24) . However, it is likely that the spinal networks that contribute to human locomotion are more dependent on supraspinal centers than those in quadrupedal animals.…”

Section: Discussionmentioning

confidence: 99%

Difference in Upper Extremity Spinal Motor Neuron Excitability and Function during Walking and Stepping in Place

et al. 2012

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Abstract.[Purpose] We analyzed F-waves obtained during walking and stepping in place by healthy subjects to investigate changes in upper extremity spinal motor neuron excitability.[Subjects] Twenty-six healthy subjects were evaluated before, during, and after walking and stepping in place. [Methods] We recorded F-waves from the Abductor Pollicis Brevis muscle of the upper extremity before, during and after walking and stepping in place.[Results] F-wave persistence significantly increased during walking compared to persistence before and after walking. There was no significant change in F/M amplitude ratio and F-wave latency values during walking when compared to before and after walking. All parameters of F-waves demonstrated a statistically significant increase during stepping in place when compared to before and after stepping in place. [Conclusion] These findings indicate that upper extremity spinal motor neurons excitability increases during stepping in place, but only the firing frequency of the upper extremity α motor neuron increases during walking. Our findings suggest that seemingly similar movements such as walking and stepping in place are neurophysiologically distinct. Therefore, caution is required when working with neurologically impaired individuals, and it is important to be aware of the impact of each exercise.

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“…This neural network can be found in the spinal cord of all vertebrates, like the lamprey [66] and mammals [48] including humans [49,67,68]. The locomotor CPG may produce coordinated motor patterns in isolation.…”

Section: The Locomotor Systemmentioning

confidence: 99%