Effects of body to head rotation on the labyrinthine responses of rat vestibular neurons

M. Barresi, C. Grasso, G. Li Volsi, D. Manzoni
Neuroscience. 2013-08-01; 244: 134-146
DOI: 10.1016/j.neuroscience.2013.04.010

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1. Neuroscience. 2013 Aug 6;244:134-46. doi: 10.1016/j.neuroscience.2013.04.010.
Epub 2013 Apr 13.

Effects of body to head rotation on the labyrinthine responses of rat vestibular

Barresi M(1), Grasso C, Li Volsi G, Manzoni D.

Author information:
(1)Department of Translational Research and New Technologies in Medicine and
Surgery, University of Pisa, I-56127 Pisa, Italy.

Vestibulospinal reflexes elicited by head displacement in space depend on the
direction of body displacement, because the neuronal responses to labyrinthine
stimulation are tuned by neck displacement: a directional tuning takes place in
the medial cerebellum and in spinal motoneurons, while a gain and a basal
activity tuning can be observed in the reticular formation, a target structure of
the medial cerebellum. In the present study, we investigated whether also the
response of vestibular nuclear neurons (another target of the medial cerebellum)
to labyrinthine stimulation is tuned by neck displacement and which parameters of
the response are modulated by it. In urethane-anaesthetized Wistar rats,
single-unit activity was recorded from the vestibular nuclei at rest and during
wobble of the whole animal at 0.156 Hz. This stimulus tilted the animal’s head by
a constant amplitude (5°), in a direction rotating at a constant velocity over
the horizontal plane, either in clockwise or counter clockwise direction. The
gain and the direction of neuronal responses to wobble were evaluated through
Fourier analysis, in the control position (with coincident head and body axes)
and following a body-to-head rotation of 5-30° over the horizontal plane, in both
directions. Most of the vestibular neurons modified their response gain and/or
their basal activity following body-to-head rotation, as it occurs in the
reticular formation. Only few neurons modified their response direction, as
occurs in the cerebellum and in spinal motoneurons. The different behaviour of
cerebellar neurons and of their vestibular and reticular target cells, suggests
that the role played by the cerebellum in the neck tuning of vestibulospinal
reflexes has to be reconsidered.

Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

DOI: 10.1016/j.neuroscience.2013.04.010
PMID: 23587843 [Indexed for MEDLINE]

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