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There is some discrepancy over the extent to which reflex pathways from different cutaneous nerves in the hand and foot link the cervical and lumbar spinal cord in neurologically intact humans. The present experiments were designed to determine whether stimulation of a cutaneous nerve in the foot or in the hand evoked reflexes in the non-stimulated limbs(More)
There continues to be great interest in evaluating the adaptive plasticity of the human nervous system in response to exercise training or other interventions. For various reasons, researchers have been interested in estimates of spinal reflex processing in intact human subjects before and after training. A reflex pathway that has been employed in this(More)
1. The organization and pattern of cutaneous reflex modulation during rhythmic cyclical movements of the human upper limbs has received much less attention than that afforded the lower limb. Our working hypothesis is that control mechanisms underlying the modulation of cutaneous reflex amplitude during rhythmic arm movement are similar to those that control(More)
The functions of ipsilateral cutaneous reflexes were studied with short trains of stimuli presented pseudorandomly to the superficial peroneal (SP) and tibial nerves during human gait. Electromyograms (EMGs) of tibialis anterior (TA), soleus, lateral and medial gastrocnemius, vastus lateralis (VL), and biceps femoris (BF) muscle were recorded, together with(More)
Studies on the reflex modulation of vertebrate locomotion have been conducted in many different laboratories and with many different preparations: for example, lamprey swimming, bird flight, quadrupedal walking in cats and bipedal walking in humans. Emerging concepts are that reflexes are task-, phase- and context-dependent. To function usefully in a(More)
Walking can be a very automated process, and it is likely that central pattern generators (CPGs) play a role in the coordination of the limbs. Recent evidence suggests that both the arms and legs are regulated by CPGs and that sensory feedback also regulates the CPG activity and assists in mediating interlimb coordination. Although the strength of coupling(More)
Reflexes undergo modulation according to task and timing during standing, walking, running, and leg cycling in humans. Both cutaneous and Hoffman (H-) reflexes are modulated by movement and task. However, recent evidence suggests that the modulation pattern for cutaneous and H-reflexes may be different. We sought to clarify this issue by reducing the effect(More)
Although we move our arms rhythmically during walking, running, and swimming, we know little about the neural control of such movements. Our working hypothesis is that neural mechanisms controlling rhythmic movements are similar in the human lumbar and cervical spinal cord. Thus reflex modulation during rhythmic arm movement should be similar to that seen(More)
During locomotor tasks such as walking, running, and swimming, the arms move rhythmically with the legs. It has been suggested that connections between the cervical and lumbosacral spinal cord may mediate some of this interlimb coordination. However, it is unclear how these interlimb pathways modulate reflex excitability during movement. We hypothesized(More)
Rhythmic motor patterns are ubiquitous in the animal kingdom. Walking, cycling, and swimming are examples of rhythmic locomotor tasks that humans perform routinely. This paper outlines the common core hypothesis that rhythmic motor patterns in human locomotion share common central neural control mechanisms. This is subserved by presumed central pattern(More)