Roles of axon guidance molecules in neuronal wiring in the developing spinal cord

Abstract

The spinal cord receives, relays and processes sensory information from the periphery and integrates this information with descending inputs from supraspinal centres to elicit precise and appropriate behavioural responses and orchestrate body movements. Understanding how the spinal cord circuits that achieve this integration are wired during development is the focus of much research interest. Several families of proteins have well-established roles in guiding developing spinal cord axons, and recent findings have identified new axon guidance molecules. Nevertheless, an integrated view of spinal cord network development is lacking, and many current models have neglected the cellular and functional diversity of spinal cord circuits. Recent advances challenge the existing spinal cord axon guidance dogmas and have provided a more complex, but more faithful, picture of the ontogenesis of vertebrate spinal cord circuits.

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Fig. 1: Guidance of motor axons to their exit points.
Fig. 2: The development of sensory projections.
Fig. 3: Semaphorins control sensory axon guidance.
Fig. 4: The development of contralateral and ipsilateral circuits.

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Acknowledgements

A.C. is supported by grants from the Agence Nationale de la Recherche (ANR; ANR-14-CE13-0004-01), the LABEX LIFESENSES (reference ANR-10-LABX-65) and French state funds managed by the ANR within the Investissements d’Avenir programme under reference ANR-11-IDEX-0004-02.

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Nature Reviews Neuroscience thanks G. Bashaw, D. Bonanomi, Y. Zou and other anonymous reviewer(s) for their contribution to the peer review of this work.

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Glossary

Propriospinal neurons

Interneurons distributed along the spinal cord that connect multiple spinal cord segments and project to the brain. They play a role in the coordination of locomotion and proprioception.

Ventricular zone

(VZ). The cellular layer lining the CNS ventricles that contains proliferating neural progenitors (radial glia).

Marginal zone

The cell-poor superficial region of the developing CNS that is located under the basal lamina.

Axonal adhesion

The process that allows axons to adhere preferentially to some cells or substrates containing cell adhesion molecules that exert adhesive forces on the axon.

Fasciculation

The mechanism through which growing axons extend along other axons and adhere to each other forming tracts and bundles.

Pyramidal decussation

The region at the junction of the brainstem and spinal cord at which axons of the corticospinal tract deviate dorsally and cross the midline.

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Chédotal, A. Roles of axon guidance molecules in neuronal wiring in the developing spinal cord. Nat Rev Neurosci 20, 380–396 (2019). https://doi.org/10.1038/s41583-019-0168-7

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