Perturbation-evoked cortical activity reflects both the context and consequence of postural instability

• Published in: Neuroscience 2010-10, Vol.170 (2), p.599-609
• Main Authors: Mochizuki, G, Boe, S, Marlin, A, McIlroy, W.E
• Format: Article
• Language: English
• Subjects: Auditory evoked potentials; balance; Biological and medical sciences; Cerebral Cortex - physiology; Electroencephalography; Electromyography; evoked potentials; Evoked Potentials - physiology; Female; Fundamental and applied biological sciences. Psychology; human; Humans; Male; Muscle, Skeletal - physiology; Neurology; Postural Balance - physiology; postural set; Vertebrates: nervous system and sense organs
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2010.07.008

Abstract 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 and possible meaning of these different events (pre- vs. post-) there is little insight into the possible association between them. The purpose of this study was to explore whether pre- and post-perturbation cortical events are associated or whether they reflect different control processes linked to the control of balance. Twelve participants were presented temporally-predictable postural perturbations under four test conditions. The Block/Random tasks were designed to assess modifiability in CNS gain prior to instability, while the Unconstrained/Constrained tasks assessed responsiveness to the magnitude of instability. Perturbations were evoked by releasing a cable which held the participant in a forward lean position. The magnitude of pre-perturbation cortical activity scaled to perturbation amplitude when the magnitude of the perturbation was predictable [ F (3,11)=2.906, P