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How is load sensed by receptors, and how is this sensory information used to guide locomotion? Many insights in this domain have evolved from comparative studies since it has been realized that basic principles concerning load sensing and regulation can be found in a wide variety of animals, both vertebrate and invertebrate. Feedback about load is not only(More)
1. Neurons in the ventral intraparietal area (VIP) are known to respond to translating random dot patterns. Such responses can be explained on the basis of the input of the middle temporal area (MT) to this area. Anatomic evidence has shown that VIP receives input from the dorsal part of the medial superior temporal area (MSTd) also. Neurons in the latter(More)
The purpose of the present study was to determine whether tactile cutaneous reflexes from the skin of the foot contain location-specific information during human walking. Muscular responses to non-nociceptive electrical stimulation of the sural, posterior tibial, and superficial peroneal nerves, each supplying a different skin area of the foot, were studied(More)
Phase-dependent reflex modulation was studied by recording the electromyographic (EMG) responses in ankle flexors (Tibialis Anterior, TA) and extensors (Gastrocnemius Medialis, GM and Soleus, SOL) to a 20 ms train of electrical pulses, applied to the tibial or sural nerve at the ankle, in human volunteers walking on a treadmill at 4 km/h. For low intensity(More)
Whereas behavioral studies have made significant contributions toward the identification of the principles governing the coordination of limb movements, little is known about the role of higher brain areas that are involved in interlimb coordination. Functional magnetic resonance imaging (fMRI) was used to reveal the brain areas activated during the(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)
Human interlimb coordination and the adaptations in leg muscle activity were studied during walking on a treadmill with split belts. Four different belt speeds (0.5, 1.0, 1.5, 2.0 m/s) were offered in all possible combinations for the left and right leg. Subjects adapted automatically to a difference in belt speed within 10–20 stride cycles.This adaptation(More)
A basic aspect of the neuronal control of quadrupedal locomotion of cat and of bipedal stance and gait of humans concerns the antigravity function of leg extensors. In humans proprioceptive reflexes involved in the maintenance of body equilibrium depend on the presence of contact forces opposing gravity. Extensor load receptors are thought to signal changes(More)
1. Stimulation of different hindlimb nerves in spontaneously walking premammillary cats was used in order to examine the effects of sensory input on the rhythmic motor output. 2. Stimulation of the tibial or sural nerve at low intensities caused the burst of activity in the triceps surae or semimembranosus to be prolonged if stimuli were given during the(More)
Following hemiparetic stroke, the timing of lower extremity muscle activity during gait often undergoes radical changes. In the present study, we compared the duration of activity in Biceps femoris (BF), Rectus femoris (RF), Tibialis anterior (TA) and Gastrocnemius medialis (GM) for four subphases of the gait cycle: the first double support phase (DS1), the(More)