Neuron-intrinsic limitations to axon regeneration in the developing spinal cord

摘要: Axons in the spinal cord of adult birds and mammals are unable to regenerate if they are severed by injury, so paralysis and loss of sensation are permanent. A major goal of neuroscience research is to identify and overcome the factors that limit axon regeneration. Unlike adults, embryonic animals do regenerate axons in the spinal cord, but lose this ability during a discrete developmental transition. This transition provides a point of entry into the problem of spinal cord injury. The basic strategy of my thesis work is to use the spinal cord of the embryonic chicken as a model to ask basic questions about how regeneration succeeds in the young spinal cord and why it fails in the adult. I first address the fundamental question of whether axon growth is limited more by the environment of the spinal cord or by the internal state of neurons, and demonstrate that changes in developing neurons are central to the failure of axon …