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The cerebral cortex may play a role in the control of compensatory balance reactions by optimizing these responses to suit the task conditions and/or to stimulus (i.e. perturbation) characteristics. These possible contributions appear to be reflected by pre-perturbation and post-perturbation cortical activity. While studies have explored the characteristics(More)
This study investigated the effects of postural set on the cortical response evoked by an external perturbation to human upright stance. Postural set was manipulated by providing either predictable or unpredictable whole body perturbations which required balance corrections to maintain upright stability. Unpredictable perturbations evoked a large negative(More)
Studies are reviewed, predominantly involving healthy humans, on gain changes in spinal reflexes and supraspinal ascending paths during passive and active leg movement. The passive movement research shows that the pathways of H reflexes of the leg and foot are down-regulated as a consequence of movement-elicited discharge from somatosensory receptors,(More)
Healthy young adults (n = 39) were asked to perform four different secondary cognitive tasks during quiet unperturbed stance, in order to investigate the influence of physiological arousal and attention distraction on the control of spontaneous postural sway. During each task, postural activity was quantified in terms of center-of-pressure displacement,(More)
To determine the potential differences in control underlying compensatory and voluntary reach-to-grasp movements the current study compared the kinematic and electromyographic profiles associated with upper limb movement. Postural perturbations were delivered to evoke compensatory reach-to-grasp in ten healthy young adult volunteers while seated on a chair(More)
Previous studies of compensatory stepping, in response to postural perturbation, have focussed on forward or backward stepping; however, the ability to step in other directions is of equal functional importance, since the perturbations encountered in daily life may often include a lateral component. The primary objective of this study was to determine how(More)
The role of plantar pressure sensation in controlling compensatory stepping was explored via hypothermic anesthesia of the foot soles, in 10 healthy young adults. Stepping reactions were evoked by unpredictable platform translation in forward, backward and lateral directions. The findings suggest three specific direction- and phase-dependent roles for the(More)
Age-related changes in the neural, sensory, and musculoskeletal systems can lead to balance impairments that have a tremendous impact on the ability to move about safely. The many complex substrates of the posture control system subserve a common functional goal: regulation of the relationship between the center of mass and the base of support. Traditional(More)
BACKGROUND AND PURPOSE In the undamaged brain, sensory input to the cortex is intricately controlled via sensory gating mechanisms. Given the role of corticothalamic pathways in this control, it was hypothesized that in patients recovering from thalamic stroke there would be evidence of disrupted sensory gating and that efficient control of cortical sensory(More)
BACKGROUND Although previous studies suggest that postural control requires attention and other cognitive resources, the central mechanisms responsible for this relationship remain unclear. To address this issue, we examined the effects of altered attention on cortical activity and postural responses following mechanical perturbations to upright stance. We(More)