- 作者: Y.S. Chan a, C.H. Lai a, D.K.Y. Shum b
- 作者服務機構: Departments of a Physiology and b Biochemistry, Faculty of Medicine, The University of Hong Kong, Hong Kong China
- 中文摘要: --
- 英文摘要: firmed and extended previous observations that therecovery of resting activity within the vestibular nuclearcomplex during vestibular compensation is related tochanges in both intrinsic membrane properties and ca-pacities to respond to extracellular factors. The bilateralimbalance provides the basis for deranged spatial cod-ing and motor deficits accompanying hemilabyrinthecto-my. Taken together, these experimental findings indicatethat in the normal state converging inputs from bilateralvestibular labyrinths are essential to spatiotemporal sig-nal transformation at the central otolith neurons duringlow-frequency head movements.Recent work on the coding of spatial information in cen-tral otolith neurons has significantly advanced ourknowledge of signal transformation from head-fixedotolith coordinates to space-centered coordinates duringmotion. In this review, emphasis is placed on the neuralmechanisms by which signals generated at the bilaterallabyrinths are recognized as gravity-dependent spatialinformation and in turn as substrate for otolithic reflexes.We first focus on the spatiotemporal neuronal responsepatterns (i.e. one- and two-dimensional neurons) to pureotolith stimulation, as assessed by single unit recordingfrom the vestibular nucleus in labyrinth-intact animals.These spatiotemporal features are also analyzed in asso-ciation with other electrophysiological properties to eval-uate their role in the central construction of a spatialframe of reference in the otolith system. Data derivedfrom animals with elimination of inputs from one laby-rinth then provide evidence that during vestibular stimu-lation signals arising from a single utricle are operativeat the level of both the ipsilateral and contralateral ves-tibular nuclei. Hemilabyrinthectomy also revealed neuralasymmetries in spontaneous activity, response dynam-ics and spatial coding behavior between neuronal sub-populations on the two sides and as a result suggested asegregation of otolith signals reaching the ipsilateral andcontral ateralvesti bular nuclei. Recent studies have con-
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