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PLoS One. 2016 May 4;11(5):e0155058. doi: 10.1371/journal.pone.0155058. eCollection 2016.

Dopamine Modulates Motor Control in a Specific Plane Related to Support.

Author information

1
UMR 7179 MNHN/CNRS, Museum National d'Histoire Naturelle, Dpt EGB, CP 55, 57 rue Cuvier 75231 Paris cedex 05, France.
2
MENESR, DEPP, 61-65 rue Dudot 75015 Paris, France.
3
LJK, CNRS UMR 5224 INRIA/UJF, INRIA Rhône-Alpes, 655 av de l'Europe, 38330 Montbonnot, France.
4
SLEEP Physiopathologie des réseaux neuronaux du cycle sommeil, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR5292, Faculté de Médecine Laennec, 7 rue Guillaume Paradin, 69372 LYON Cedex 08 France.
5
Centre de Neurophysique, Physiologie, Pathologie, Université Paris Descartes-CNRS UMR-8119, 45 rue des Saint-Pères, 75270 Paris cedex 06, France.
6
Centre de Psychiatrie et Neurosciences, INSERM UMR 894-Université Paris Descartes, 2ter, rue d'Alésia, 78014 Paris, France.
7
COGNAC-G Université Paris Descartes-CNRS UMR-MD-SSA, 45 rue des Saint-Pères, 75270 Paris cedex 06, France.

Abstract

At the acute stage following unilateral labyrinthectomy (UL), rats, mice or guinea pigs exhibit a complex motor syndrome combining circling (HSCC lesion) and rolling (utricular lesion). At the chronic stage, they only display circling, because proprioceptive information related to the plane of support substitutes the missing utricular information to control posture in the frontal plane. Circling is also observed following unilateral lesion of the mesencephalic dopaminergic neurons by 6- hydroxydopamine hydrobromide (6-OHDA rats) and systemic injection of apomorphine (APO rats). The resemblance of behavior induced by unilateral vestibular and dopaminergic lesions at the chronic stage can be interpreted in two ways. One hypothesis is that the dopaminergic system exerts three-dimensional control over motricity, as the vestibular system does. If this hypothesis is correct, then a unilateral lesion of the nigro-striatal pathway should induce three-dimensional motor deficits, i.e., circling and at least some sort of barrel rolling at the acute stage of the lesion. Then, compensation could also take place very rapidly based on proprioception, which would explain the prevalence of circling. In addition, barrel rolling should reappear when the rodent is placed in water, as it occurs in UL vertebrates. Alternatively, the dopaminergic network, together with neurons processing the horizontal canal information, could control the homeostasis of posture and locomotion specifically in one and only one plane of space, i.e. the plane related to the basis of support. In that case, barrel rolling should never occur, whether at the acute or chronic stage on firm ground or in water. Moreover, circling should have the same characteristics following both types of lesions. Clearly, 6-OHDA and APO-rats never exhibited barrel rolling at the acute stage. They circled at the acute stage of the lesion and continued to do so three weeks later, including in water. In contrast, UL-rats, exhibited both circling and barrel rolling at the acute stage, and then only circled on the ground. Furthermore, barrel rolling instantaneously reappeared in water in UL rats, which was not the case in 6-OHDA and APO-rats. That is, the lesion of the dopaminergic system on one side did not compromise trim in the pitch and roll planes, even when proprioceptive information related to the basis of support was lacking as in water. Altogether, these results strongly suggest that dopamine does not exert three-dimensional control of the motor system but regulates postural control in one particular plane of space, the one related to the basis of support. In contrast, as previously shown, the vestibular system exerts three-dimensional control on posture. That is, we show here for the first time a relationship between a given neuromodulator and the spatial organization of motor control.

PMID:
27145032
PMCID:
PMC4856377
DOI:
10.1371/journal.pone.0155058
[Indexed for MEDLINE]
Free PMC Article

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