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Article: Neuronal response sensitivity to bidirectional off-vertical axis rotations: A dimension of imbalance in the bilateral vestibular nuclei of cats after unilateral labyrinthectomy

TitleNeuronal response sensitivity to bidirectional off-vertical axis rotations: A dimension of imbalance in the bilateral vestibular nuclei of cats after unilateral labyrinthectomy
Authors
KeywordsBidirectional response sensitivity
Hemilabyrinthectomy
Off-vertical axis rotation
Otolith
Vestibular nuclear neuron
Issue Date1999
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/neuroscience
Citation
Neuroscience, 1999, v. 94 n. 3, p. 831-843 How to Cite?
AbstractIn decerebrate cats after acute hemilabyrinthectomy, the response sensitivity of extracellularly recorded vestibular nuclear neurons on the lesioned and labyrinth-intact sides were examined quantitatively during constant velocity off-vertical axis rotations with an aim to elucidate the functional contribution of otolithic inputs to the ipsilateral and contralateral vestibular nuclei. The bidirectional response sensitivity, δ, was determined as the ratio of the gain during clockwise to that during counterclockwise rotations. A continuum of response sensitivity was identified: one-dimensional neurons showed symmetrically bidirectional response patterns, while two-dimensional neurons showed asymmetrically bidirectional patterns that in some cases approached unidirectional patterns with change in velocity. The proportion of two-dimensional neurons was significantly increased after acute hemilabyrinthectomy. Two-dimensional neurons that responded only to one direction of rotation in at least one of the velocities tested were described as unidirectional neurons. This unidirectional response pattern was observed in one-third of the entire neuronal population studied, but not in cats with both labyrinths intact, thus suggesting that such prominent broadly tuned responses are normally masked by converging otolithic inputs from the contralateral side. These neurons were found in higher proportion on the lesioned side than on the labyrinth-intact side. Among the 70% of unidirectional neurons that exhibited bidirectional response at some velocities and unidirectional response at others, prominent shifts in δ values (i.e. between 0/∞ and finite values) with velocity can be computed for each neuron. The shifts in δ values correlated with large shifts in the response dynamics and spatial orientation as the response pattern changed with velocity. The response orientations of the unidirectional neurons pointed in all directions on the horizontal plane. When all the two-dimensional neurons (i.e. both the unidirectionally and bidirectionally responsive ones) were pooled, imbalances in the distribution of the response orientations and in response gain were found between the ipsilateral-side-down/head-down half-circle and the contralateral-side- down/head-up half-circle on the labyrinth-intact side, but not on the lesioned side. These results, derived from spatiotemporal processing of gravitational signals, reveal a novel dimension of imbalance between neuronal populations in the two vestibular nuclear complexes after acute lesion of one labyrinth. This feature would provide, on the one hand, deranged cues of spatial orientation and direction during slow head excursions and, on the other, a framework for the dynamic behavioral deficits associated with hemilabyrinthectomy.
Persistent Identifierhttp://hdl.handle.net/10722/68221
ISSN
2015 Impact Factor: 3.231
2015 SCImago Journal Rankings: 1.768
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorChan, YSen_HK
dc.contributor.authorShum, DKYen_HK
dc.contributor.authorLai, CHen_HK
dc.date.accessioned2010-09-06T06:02:31Z-
dc.date.available2010-09-06T06:02:31Z-
dc.date.issued1999en_HK
dc.identifier.citationNeuroscience, 1999, v. 94 n. 3, p. 831-843en_HK
dc.identifier.issn0306-4522en_HK
dc.identifier.urihttp://hdl.handle.net/10722/68221-
dc.description.abstractIn decerebrate cats after acute hemilabyrinthectomy, the response sensitivity of extracellularly recorded vestibular nuclear neurons on the lesioned and labyrinth-intact sides were examined quantitatively during constant velocity off-vertical axis rotations with an aim to elucidate the functional contribution of otolithic inputs to the ipsilateral and contralateral vestibular nuclei. The bidirectional response sensitivity, δ, was determined as the ratio of the gain during clockwise to that during counterclockwise rotations. A continuum of response sensitivity was identified: one-dimensional neurons showed symmetrically bidirectional response patterns, while two-dimensional neurons showed asymmetrically bidirectional patterns that in some cases approached unidirectional patterns with change in velocity. The proportion of two-dimensional neurons was significantly increased after acute hemilabyrinthectomy. Two-dimensional neurons that responded only to one direction of rotation in at least one of the velocities tested were described as unidirectional neurons. This unidirectional response pattern was observed in one-third of the entire neuronal population studied, but not in cats with both labyrinths intact, thus suggesting that such prominent broadly tuned responses are normally masked by converging otolithic inputs from the contralateral side. These neurons were found in higher proportion on the lesioned side than on the labyrinth-intact side. Among the 70% of unidirectional neurons that exhibited bidirectional response at some velocities and unidirectional response at others, prominent shifts in δ values (i.e. between 0/∞ and finite values) with velocity can be computed for each neuron. The shifts in δ values correlated with large shifts in the response dynamics and spatial orientation as the response pattern changed with velocity. The response orientations of the unidirectional neurons pointed in all directions on the horizontal plane. When all the two-dimensional neurons (i.e. both the unidirectionally and bidirectionally responsive ones) were pooled, imbalances in the distribution of the response orientations and in response gain were found between the ipsilateral-side-down/head-down half-circle and the contralateral-side- down/head-up half-circle on the labyrinth-intact side, but not on the lesioned side. These results, derived from spatiotemporal processing of gravitational signals, reveal a novel dimension of imbalance between neuronal populations in the two vestibular nuclear complexes after acute lesion of one labyrinth. This feature would provide, on the one hand, deranged cues of spatial orientation and direction during slow head excursions and, on the other, a framework for the dynamic behavioral deficits associated with hemilabyrinthectomy.en_HK
dc.languageengen_HK
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/neuroscienceen_HK
dc.relation.ispartofNeuroscienceen_HK
dc.rightsNeuroscience. Copyright © Elsevier BV.en_HK
dc.subjectBidirectional response sensitivityen_HK
dc.subjectHemilabyrinthectomyen_HK
dc.subjectOff-vertical axis rotationen_HK
dc.subjectOtolithen_HK
dc.subjectVestibular nuclear neuronen_HK
dc.subject.meshAnimalsen_HK
dc.subject.meshCatsen_HK
dc.subject.meshEar, Inner - physiologyen_HK
dc.subject.meshElectrophysiology - methodsen_HK
dc.subject.meshFunctional Lateralityen_HK
dc.subject.meshMotor Activity - physiologyen_HK
dc.subject.meshNeurons - physiologyen_HK
dc.subject.meshRotationen_HK
dc.subject.meshVestibular Nuclei - physiologyen_HK
dc.titleNeuronal response sensitivity to bidirectional off-vertical axis rotations: A dimension of imbalance in the bilateral vestibular nuclei of cats after unilateral labyrinthectomyen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0306-4522&volume=94&spage=831&epage=843&date=1999&atitle=Neuronal+response+sensitivity+to+bidirectional+off-vertical+axis+rotations:+A+dimension+of+imbalance+in+the+bilateral+vestibular+nuclei+of+cats+after+unilateral+labyrinthectomyen_HK
dc.identifier.emailChan, YS: yschan@hkucc.hku.hken_HK
dc.identifier.emailShum, DKY: shumdkhk@hkucc.hku.hken_HK
dc.identifier.emailLai, CH: chlaib@hku.hken_HK
dc.identifier.authorityChan, YS=rp00318en_HK
dc.identifier.authorityShum, DKY=rp00321en_HK
dc.identifier.authorityLai, CH=rp00396en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/S0306-4522(99)00374-7en_HK
dc.identifier.pmid10579574-
dc.identifier.scopuseid_2-s2.0-0032846190en_HK
dc.identifier.hkuros53665en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0032846190&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume94en_HK
dc.identifier.issue3en_HK
dc.identifier.spage831en_HK
dc.identifier.epage843en_HK
dc.identifier.isiWOS:000083250900016-
dc.publisher.placeNetherlandsen_HK
dc.identifier.scopusauthoridChan, YS=7403676627en_HK
dc.identifier.scopusauthoridShum, DKY=7004824447en_HK
dc.identifier.scopusauthoridLai, CH=7403086597en_HK

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