A neuronal substrate for a state-dependent modulation of sensory inputs in the brainstem

Authors

  • Didier Le Ray,

    1. Université de Bordeaux, CNRS, Laboratoire Mouvement Adaptation Cognition, Bordeaux, France
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  • Laurent Juvin,

    1. Groupe de Recherche sur le Système Nerveux Central, Département de Physiologie, Université de Montréal, Montréal, QC, Canada
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  • Tanguy Boutin,

    1. Groupe de Recherche sur le Système Nerveux Central, Département de Physiologie, Université de Montréal, Montréal, QC, Canada
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  • François Auclair,

    1. Groupe de Recherche sur le Système Nerveux Central, Département de Physiologie, Université de Montréal, Montréal, QC, Canada
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  • Réjean Dubuc

    1. Groupe de Recherche sur le Système Nerveux Central, Département de Physiologie, Université de Montréal, Montréal, QC, Canada
    2. Département de kinanthropologie, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montréal, QC, Canada H3C 3P8
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Dr R. Dubuc, 3Département de kinanthropologie, as above.
E-mail: dubuc.rejean@uqam.ca

Abstract

Central networks modulate sensory transmission during motor behavior. Sensory inputs may thus have distinct impacts according to the state of activity of the central networks. Using an in-vitro isolated lamprey brainstem preparation, we investigated whether a brainstem locomotor center, the mesencephalic locomotor region (MLR), modulates sensory transmission. The synaptic responses of brainstem reticulospinal (RS) cells to electrical stimulation of the sensory trigeminal nerve were recorded before and after electrical stimulation of the MLR. The RS cell synaptic responses were significantly reduced by MLR stimulation and the reduction of the response increased with the stimulation intensity of the MLR. Bath perfusion of atropine prevented the depression of sensory transmission, indicating that muscarinic receptor activation is involved. Previous studies have shown that, upon stimulation of the MLR, behavioral activity switches from a resting state to an active-locomotor state. Therefore, our results suggest that a state-dependent modulation of sensory transmission to RS cells occurs in the behavioral context of locomotion and that muscarinic inputs from the MLR are involved.

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