Spinal corollary discharge modulates motion sensing during vertebrate locomotion.
During active movements, neural replicas of the underlying motor commands may assist in adapting motion-detecting sensory systems to an animal's own behaviour. The transmission of such motor efference copies to the mechanosensory periphery offers a potential predictive substrate for diminishing sensory responsiveness to self-motion during vertebrate locomotion. Here, using semi-isolated in vitro preparations of larval Xenopus, we demonstrate that shared efferent neural pathways to hair cells of vestibular endorgans and lateral line neuromasts express cyclic impulse bursts during swimming that are directly driven by spinal locomotor circuitry. Despite common efferent innervation and discharge patterns, afferent signal encoding at the two mechanosensory peripheries is influenced differentially by efference copy signals, reflecting the different organization of body/water motion-detecting processes in the vestibular and lateral line systems. The resultant overall gain reduction in sensory signal encoding in both cases, which likely prevents overstimulation, constitutes an adjustment to increased stimulus magnitudes during locomotion.
Department of Biology II, Ludwig-Maximilians-University Munich, Grosshadernerstrasse 2, 82152 Planegg-Martinsried, Germany.
Boris P
BP
Chagnaud
Department of Biology II, Ludwig-Maximilians-University Munich, Grosshadernerstrasse 2, 82152 Planegg-Martinsried, Germany.|Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Planegg-Martinsried 82152, Germany.
Roberto
R
Banchi
Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Université de Bordeaux, CNRS UMR 5287, 33076 Bordeaux, France.
John
J
Simmers
Department of Biology II, Ludwig-Maximilians-University Munich, Grosshadernerstrasse 2, 82152 Planegg-Martinsried, Germany.
Hans
H
Straka
D000818:Animals; D018069:Hair Cells, Vestibular / Q000502:physiology*; D066298:In Vitro Techniques; D007699:Kinesthesis / Q000502:physiology*; D007814:Larva; D053403:Lateral Line System / Q000502:physiology*; D008124:Locomotion / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D009476:Neurons, Efferent / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*; D013550:Swimming; D014725:Vestibular Nerve / Q000502:physiology; D014982:Xenopus laevis