We have previously suggested that the discharge characteristics of some neurons in pontomedullary reticular formation (PMRF) are contingent on simultaneous requirement for activity both ipsilateral flexor muscles and contralateral extensors. To test this hypothesis we trained cats to stand four force platforms perform a task which they were required reach forward with one forelimb or other depress lever. As such cat make flexion movement followed by an extension reaching limb while...

This study was designed to determine the contribution of reticular neurons in pontomedullary formation (PMRF) postural responses produced compensate for an unexpected perturbation. We recorded activity 48 PMRF, including 41 reticulospinal neurons, removal support surface under each four limbs cats. The perturbations robust that were divided into three periods: initial response (P1) displaced center vertical pressure over two diagonal supporting limbs; a secondary (P2) during which cat...

The purpose of this study was to analyze and compare the features center mass (CoM) control along anterior/posterior axis in young elderly subjects during sit-to-stand (STS). From a sitting position, seven healthy were asked stand up from chair under different experimental conditions (visual conditions: normal blindfolded; speed: as fast possible). Analysis results based upon concept "dynamic equilibrium area" (DEA), which turn identified dynamic limits balance. showed that both maximal CoM...

We examined the spatial organization of feedforward postural adjustments produced prior to and during voluntary arm reaching movements executed while standing. sought investigate whether activity muscles before was directionally tuned a strategy horizontal force constraint could be observed. To this end, eight human subjects self-paced reach-to-point on random illumination one 13 light targets placed within 180° array centered along midline body. Analysis divided into two periods: first...

THE purpose of this study was to examine the role anticipatory postural adjustments (APAs) in execution forward oriented whole body reaching movements. From standing position, eight healthy subjects were asked reach an object placed at 45 cm from feet, both naturally paced and fast speeds. Electromyographic signals six antagonistic muscles analysed conjunction with centre mass (CM) displacements, foot pressure displacements resultant ground reaction forces. Results revealed that APAs created...

Pyridoxine given in large doses is thought to destroy selectively the large-diameter peripheral sensory nerve fibers, leaving motor fibers intact. This study examined effects of pyridoxine-induced somatosensory loss on automatic postural responses sudden displacements support surface standing cat. Two cats were trained stand four force plates mounted a movable platform. They pyridoxine (350 mg/kg, i.p.) 2 successive days (0 and 1). Electromyographic (EMG) activity was recorded from selected...

The aim of this study was to investigate how humans correct ongoing arm movements while standing. Specifically, we sought understand whether the postural adjustments in legs required for online corrections are predictive or rely on feedback from moving limb. To answer question measured and leg muscles during pointing Nine healthy right-handed subjects reached with their dominant a visual target front them aligned midline. In some trials, position would switch central one other targets...

Although the balance difficulties accompanying vestibular loss are well known, underlying cause remains unclear. We examined role of inputs in automatic postural response (APR) to pitch and roll rotations support surface freely standing cats before first week after bilateral labyrinthectomy. Support accelerate body center mass toward downhill side. The normal APR consists inhibition extensors uphill limbs excitation decelerate maintain alignment with respect earth-vertical. After lesion,...

High-frequency neuromuscular electrical stimulation (HF NMES) induces muscular contractions through neural mechanisms that partially match physiological motor control. Indeed, a portion of the contraction arises from central mechanisms, whereby spinal motoneurons are recruited evoked sensory volley. However, involvement supraspinal centers control during such remains poorly understood. Therefore, we tested whether single HF NMES session applied to upper limb influences interhemispheric...

Lower-limb intersegmental coordination is a complex component of human walking. Aging may result in impairments motor control and contributing to the decline mobility inducing loss autonomy. Investigating could therefore provide insights into age-related changes neuromuscular gait. However, it unknown whether declines gait performance relates coordination. The aim this study was evaluate impact aging on lower limb kinematics kinetics during walking at conformable speed. We then assessed body...

Abstract When moving, humans must overcome intrinsic (body centered) and extrinsic (target-related) redundancy, requiring decisions when selecting one motor solution among several potential ones. During classical reaching studies the position of a salient target determines where participant should reach, constraining associated decisions. We aimed at investigating implicit variables guiding action selection faced with complexity human-environment interaction. Subjects had to perform whole...

some centenarians are engaged in regular physical activity and sometimes sporting events. we aimed to identify world records of centenarian athletes several sports determine which represented the best performance when compared all-age records, all disciplines taken together. performances achieved by were identified three disciplines: athletics, swimming cycling. The considered as an average respective speeds, except for jumping throwing events maximum distances performed considered. Within...