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Full-Text Articles in Social and Behavioral Sciences
Decoupling Of Stretch Reflex And Background Muscle Activity During Anticipatory Postural Adjustments In Humans, Siddharth Vedula, Robert Kearney, Ross Wagner, Paul Stapley
Decoupling Of Stretch Reflex And Background Muscle Activity During Anticipatory Postural Adjustments In Humans, Siddharth Vedula, Robert Kearney, Ross Wagner, Paul Stapley
Dr Paul J Stapley
We studied the evolution of stretch reXexes in relation to background electromyographic (EMG) activity in the soleus muscle preceding the onset of voluntary arm raise movements. Our objective was to investigate if changes in reXex EMG and muscle activity occur simultaneously and are similarly scaled in amplitude. Ten human subjects stood with each foot on pedals able to exert short dorsiXexor pulses during stance. Subjects were asked to product consistent voluntary arm raise movements to a target upon a visual cue. In ¼ of trials, no pulse perturbations were given, but in the remaining ¾’s of all trials pulses were …
A Common Neural Substrate For The Control Of Anticipatory And Compensatory Postural Responses, Paul Stapley, Benedicte Schepens, Trevor Drew
A Common Neural Substrate For The Control Of Anticipatory And Compensatory Postural Responses, Paul Stapley, Benedicte Schepens, Trevor Drew
Dr Paul J Stapley
We have shown previously that reticulospinal neurones (RSNs) in the brainstem pontomedullary reticular formation (PMRF) contribute to the production of the anticipatory postural adjustments (APAs) that precede reaching movements executed in a standing pOSition (Schepens and Drew, 2004, 2006; Schepens, Stapley and Drew, 2008). More recently (Stapley and Drew, 2009), we have also shown that cells in the PMRF contribute to the production of the compensatory responses that are produced by unexpected perturbations (drops) of the support surface from under one paw during quiet stance. In this poster we address the question of whether the same cells in the PMRF …
Reflex Changes Associated With Anticipatory Postural Adjustments Preceding Voluntary Arm Movements In Standing Humans, Siddharth Vedula, Paul J. Stapley, Robert E. Kearney
Reflex Changes Associated With Anticipatory Postural Adjustments Preceding Voluntary Arm Movements In Standing Humans, Siddharth Vedula, Paul J. Stapley, Robert E. Kearney
Dr Paul J Stapley
Dynamic changes in human stability, such as those induced by upper body movements, are preceded by anticipatory postural adjustments (APAs) in the rest of the body. We measured the excitability of the stretch reflex of the triceps-surae muscle group during APAs associated with unilateral right arm raises in standing humans. Our results demonstrate that reflex excitability and underlying muscle activity are linked during the APA period, but that they differ in their relative timing. This supports the idea that reflexes are controlled independently of muscle activation.