Chargé de Recherche – CNRS
Contact:
francois.lambert@u-bordeaux.fr
+33 (0)5 57 57 47 73
Site : Carreire
Domain:
Circuits and Integrative Neurosciences
Research axis:
- Ontogeny/Maturation of vestibular-based sensory-motor systems
- Interaction between vestibular function with locomotion
- Conservation of the vestibular function trough vertebrate evolution
Scientific expertise:
- Vestibular and spinal sensory-motor networks (vestibulo-ocular, vestibulo-spinal)
- Oculomotor and locomotor behavioral quantification
- Sensorimotor integration, sensory gating
- Vestibular labyrinths
- Efference copy
Research:
For the last 400 million years, the stabilization of gaze and posture represents a major requirement imposed to species to survive and adapt through evolution constrains. In this purpose vestibular-based sensory-motor transformation mechanisms constitute one of the main strategies to ensure ocular and postural corrective adjustments during active and passive body motions. Vestibulo-motor reflexes used inertial sensory inputs from inner ear endorgans to produce compensatory eye and body movements in response to head displacement. The first aspect of my research is to investigate the ontogeny of these feedback vestibular reflexes during the development. More precisely I am interested by unraveling the ontogeny of molecular, electrophysiological and networks properties of premotor and motor neuronal sub-populations involved in sensory-motor circuits that build vestibulo-ocular and vestibulo-spinal behaviors.
The sensory-motor processing that ensures gaze and posture stabilization results from the integration of vestibular inputs with other sensory and motor signals. Among them the intrinsic rhythmic locomotor pattern from spinal CPG can be directly used to set proactive feedforward eye and trunk adjustments during locomotion. This feedforward spinal pathway was first described in larval frog where a spino-extraocular motor command, based on an efference copy signal of the spinal locomotor CPG, couples the activity in extraocular motor nerves, responsible for eye movements, with the spinal motor nerve, responsible for tail myotom contraction, during undulatory swimming. This spino-extraocular motor command generates proactive conjugate eye movements that compensate the alternative tail bending, prior to feedback gaze stabilizing reflexes. The second axis of my research is to describe the ontogeny of feedforward spinal pathways, based on efference copy from CPG rhythmic pattern, that produce either ocular or body adjustments during locomotion. I explore the interaction of such a feedforward spinal pathway with classical vestibulo-ocular and vestibulo-spinal feedback reflexes. I’m also interested by both conservative and adaptative aspects of this mechanism trough the vertebrate evolution.
Models and Methods expertise:
- Xenopus frog (pre- and post-metamorphosis) and perinatal mouse
- Calcium imaging and Electrophysiogical recording technics (nerve recordings/patch-clamp) in semi-intact and isolated CNS preparations
- High-speed video recordings
- Immunolabeling and neuronal tracing
- Vestibular stimulator: motion stimulator allowing recording of either video-tracked eye/body movements or EMG/motor nerve activity in response to natural stimulation of vestibular labyrinth endorgans
Fundings:
Starting grant INCIA; ANR « Locogaze » (D. Combes); FRM team (M. Thoby-Brisson)
Main publications:
Lambert FM, Cardoit L, Courty E, Bougerol M, Thoby-Brisson M, Simmers J, Tostivint H, Le Ray D. (2018) Functional limb muscle innervation prior to cholinergic transmitter specification during early metamorphosis in Xenopus. eLife May 30;7. pii: e30693. http://www.incia.u-bordeaux1.fr/spip.php?article618.
Bacqué-Cazenave J, Courtand G, Beraneck M, Lambert FM*, Combes D.* (2018) Temporal relationship of ocular and tail segmental movements underlying locomotor-induced gaze stabilization during undulatory swimming in larval xenopus . Front. Neural Circuits, accepted. (https://www.frontiersin.org/articles/10.3389/fncir.2018.00095/abstract) doi: 10.3389/fncir.2018.00095. *co-last author. http://www.incia.u-bordeaux1.fr/spip.php?article647
Lambert FM, Bras H, Cardoit L, Vinay L, Coulon P, Glover JC. (2016) Early postnatal maturation in vestibulospinal pathways involved in neck and forelimb motor control. Dev. Neurobiol. doi: 10.1002/dneu.22375.
Kasumacic N, Lambert FM, Coulon P, Bras H, Vinay L, Perreault MC, Glover JC. (2015) Segmental organization of vestibulospinal inputs to spinal interneurons mediating crossed activation of thoracolumbar motoneurons in the neonatal mouse. J. Neurosci. 35(21):8158-69.
Lambert FM, Malinvaud D, Gratacap M, Straka H, Vidal PP. (2013) Restricted neural plasticity in vestibulospinal pathways after unilateral labyrinthectomy as the origin for scoliotic deformations. J. Neurosci. 33:6845-56.
Lambert FM, Combes D, Simmers J, Straka H. (2012) Gaze stabilization by efference copy signaling without sensory feedback during vertebrate locomotion. Curr. Biol. 22:1649-58.
Lambert FM, Malinvaud D, Glaunès J, Bergot C, Straka H, Vidal PP. (2009) Vestibular asymmetry as the cause of idiopathic scoliosis: a possible answer from Xenopus. J. Neurosci. 29, 12477-83.
Combes D, Le Ray D, Lambert FM, Simmers J, Straka H. (2008) An intrinsic feed-forward mechanism for vertebrate gaze stabilization. Curr. Biol. 18, R241-3.
Lambert FM, Beck JC, Baker R, Straka H. (2008) Semicircular canal size determines the developmental onset of angular vestibuloocular reflexes in larval Xenopus. J. Neurosci. 28, 8086-95.