caa a22 4500 445350962 CHVBK 20180317142843.0 cr unu---uuuuu 170323e20110501xx s 000 0 eng 10.1007/s00221-011-2565-7 doi (NATIONALLICENCE)springer-10.1007/s00221-011-2565-7 The human semicircular canal model of galvanic vestibular stimulation [Elektronische Daten] [Brian Day, Elijane Ramsay, Miriam Welgampola, Richard Fitzpatrick] A vector summation model of the action of galvanic stimuli on the semicircular canals has been shown to explain empirical balance and perceptual responses to binaural-bipolar stimuli. However, published data suggest binaural-monopolar stimuli evoke responses that are in the reverse direction of the model prediction. Here, we confirm this by measuring balance responses to binaural-monopolar stimulation as movements of the upper trunk. One explanation for the discrepancy is that the galvanic stimulus might evoke an oppositely directed balance response from the otolith organs that sums with and overrides the semicircular canal response. We tested this hypothesis by measuring sway responses across the full range of head pitch. The results showed some modulation of sway with pitch such that the maximal response occurred with the head in the primary position. However, the effect fell a long way short of that required to reverse the canal sway response. This indicates that the model is incomplete. Here, we examine alterations to the model that could explain both the bipolar and monopolar-evoked behavioural responses. An explanation was sought by remodelling the canal response with more recent data on the orientation of the individual canals. This improved matters but did not reverse the model prediction. However, the model response could be reversed by either rotating the entire labyrinth in the skull or by altering the gains of the individual canals. The most parsimonious solution was to use the more recent canal orientation data coupled with a small increase in posterior canal gain. The Author(s), 2011 Galvanic vestibular stimulation nationallicence Posture nationallicence Balance nationallicence Vestibular system nationallicence Semicircular canals nationallicence Day Brian Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, WC1N 3BG, London, UK aut Ramsay Elijane Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, WC1N 3BG, London, UK aut Welgampola Miriam University of Sydney, Sydney, NSW, Australia aut Fitzpatrick Richard Neuroscience Research Australia and University of New South Wales, Sydney, NSW, Australia aut Experimental Brain Research Springer-Verlag 210/3-4(2011-05-01), 561-568 0014-4819 210:3-4<561 2011 210 221 https://doi.org/10.1007/s00221-011-2565-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00221-011-2565-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Day Brian Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, WC1N 3BG, London, UK aut NATIONALLICENCE 700 1- Ramsay Elijane Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, WC1N 3BG, London, UK aut NATIONALLICENCE 700 1- Welgampola Miriam University of Sydney, Sydney, NSW, Australia aut NATIONALLICENCE 700 1- Fitzpatrick Richard Neuroscience Research Australia and University of New South Wales, Sydney, NSW, Australia aut NATIONALLICENCE 773 0- Experimental Brain Research Springer-Verlag 210/3-4(2011-05-01), 561-568 0014-4819 210:3-4<561 2011 210 221 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer