Brain, Vol. 125, No. 9, 2081-2088,
September 2002
© 2002 Guarantors of Brain
Vestibular-evoked postural responses in the absence of somatosensory information
1 MRC Human Movement Group, Sobell Department for Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London and 2 Department of Clinical Neurosciences, University of Southampton and Poole Hospital, UKCorrespondence to: B. L. Day, MRC Human Movement Group, Sobell Department for Motor Neuroscience and Movement Disorders, Institute of Neurology, Queen Square, London WC1N 3BG, UKE-mail: b.day@ion.ucl.ac.uk
In order to investigate the ways in which sensory channels interact to control balance, we measured the postural response evoked by galvanic vestibular stimulation (GVS) in a rare subject (I. W.) with a large-fibre sensory neuronopathy. I. W. has no sensations of cutaneous light touch and movement/position sense below the neck, and without vision he has no knowledge of where his limbs and body are in space. He was tested with and without vision while seated. With eyes closed, I. W.’s responses to pure vestibular stimuli were an order of magnitude larger than those of healthy controls. In other respects his responses were normal. Part of this phenomenon may have been due to lack of response modification by somatosensory feedback. However, the initial development of his ground reaction force, which is the earliest mechanical indicator of the response, differed from that of a control subject from its beginning. Similarly, opening his eyes resulted in a reduction (>50%) of the response from its beginning. We propose that these early changes reflect changes in initial response selection, possibly by alterations in the gain of vestibulopostural channels. We suggest that similar gain changes operate in healthy subjects and occur through a fast dynamic process. A model is put forward in which the weight of each sensory channel is adjusted continuously in a competitive manner according to the balance-relevant information content of the other sensory channels. As a secondary issue, the nature of I. W.’s head and trunk tilt response provides insight into the question of which vestibular afferents are recruited by GVS. I. W.’s responses consisted of an initial, relatively fast tilt followed by a slower, continuous tilt. When the stimulus was turned off, his body partially tilted back at an intermediate velocity. We modelled this behaviour as the algebraic sum of a position response and a constant velocity response. We suggest that these two components arise from stimulation of otolith and semicircular canal afferents, respectively.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  B. L. Day and M. Guerraz Feedforward versus feedback modulation of human vestibular-evoked balance responses by visual self-motion information J. Physiol., July 1, 2007; 582(1): 153 - 161. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. S. Welgampola and B. L. Day Craniocentric body-sway responses to 500 Hz bone-conducted tones in man J. Physiol., November 15, 2006; 577(1): 81 - 95. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-C. Lepecq, C. De Waele, S. Mertz-Josse, C. Teyssedre, P. T. B. Huy, P.-M. Baudonniere, and P.-P. Vidal Galvanic Vestibular Stimulation Modifies Vection Paths in Healthy Subjects J Neurophysiol, May 1, 2006; 95(5): 3199 - 3207. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Cenciarini and R. J. Peterka Stimulus-Dependent Changes in the Vestibular Contribution to Human Postural Control J Neurophysiol, May 1, 2006; 95(5): 2733 - 2750. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. B. Fallon, L. R. Bent, P. A. McNulty, and V. G. Macefield Evidence for Strong Synaptic Coupling Between Single Tactile Afferents From the Sole of the Foot and Motoneurons Supplying Leg Muscles J Neurophysiol, December 1, 2005; 94(6): 3795 - 3804. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E Jankowska, P Krutki, and K Matsuyama Relative contribution of Ia inhibitory interneurones to inhibition of feline contralateral motoneurones evoked via commissural interneurones J. Physiol., October 15, 2005; 568(2): 617 - 628. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. L. Day and R. C. Fitzpatrick Virtual head rotation reveals a process of route reconstruction from human vestibular signals J. Physiol., September 1, 2005; 567(2): 591 - 597. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Guerraz and B. L. Day Expectation and the Vestibular Control of Balance J. Cogn. Neurosci., March 1, 2005; 17(3): 463 - 469. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Cathers, B. L Day, and R. C Fitzpatrick Otolith and canal reflexes in human standing J. Physiol., February 15, 2005; 563(1): 229 - 234. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. C. Fitzpatrick and B. L. Day Probing the human vestibular system with galvanic stimulation J Appl Physiol, June 1, 2004; 96(6): 2301 - 2316. [Abstract] [Full Text] [PDF]
|
|