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Chapter 17 Synergistic interactions and functional working range of the visual and vestibular systems in postural control: neuronal correlates

1988; Elsevier BV; Linguagem: Inglês

10.1016/s0079-6123(08)64505-7

1875-7855

Christian Xerri, Liliane Borel, Jean Barthélemy, M. Lacour,

Tactile and Sensory Interactions

Comparisons between experimental data on visual-vestibular convergences at the neural, motor and perceptual levels yield the following conclusions: (1) synergistic interactions between congruent visual and vestibular signals improve velocity coding during low-frequency and steady-state body motion; (2) visual signals generally predominate over vestibular signals in the low frequency range, while the contrary applies in the higher frequency range of movement; (3) visual and vestibular inputs might be weighted depending on their internal relevance. These common interaction characteristics suggest that visual and vestibular modulation of activity in vestibular neurons might constitute at least part of the neurophy-siological substrate for visual-vestibular cooperation in postural regulation and self-motion perception. In fact, it is well known that the vestibular nuclei are involved in motor control through vestibulospinal influences [22,26,34], Nevertheless visual-vestibular convergences have been found to occur in numerous nervous structures such as the superior colliculus [8], the cerebellum [21,33], and the primary visual cortex [24,29] as well as in the vestibular cortical area [12]. Systematic investigations on the way the two modalities interact in these structures would help to determine whether the complex interactions described in this review actually take place within the vestibular nuclei or are simply reflected there after being integrated in other nervous structures.