Accurate axon targeting is a critical early step during the assembly of the neuronal network. This process requires signaling cascades that are coordinated across the growth cone plasma membrane by transmembrane axon guidance receptors. In particular, t...

Brain injuries such as stroke and trauma often lead to deficits in sensorimotor functions. Previous studies have demonstrated that reorganization of neural network in the spared brain region is one of the key processes to recover functions. The corticos...

Axon regeneration after peripheral nerve injury is slow and inefficient, leading to generally poor functional recovery. Activity-dependent experimental therapies that increase expression of brain derived neurotrophic factor (BDNF) and its trkB receptor ...

The sensory neurons in dorsal root ganglia (DRG) are pseudounipolar, projecting one axon into the periphery and another into the spinal cord. Injury to the peripheral axon results in a robust regeneration response, whereas injury to the central axon doe...

Extracellular matrix molecules, cell adhesion molecules of the Ig superfamily and neurotrophins are all capable of promoting axon growth via common signal transduction pathways. However, potential interactions among these axon growth enhancing molecules have been difficult to study because of neuronal dependence on neurotrophin stimulation for survival. To circumvent this problem, we have cultured embryonic sensory neurons from Bax-/- mice, which do not undergo apoptosis in the absence of neurotrophins (Patel et al., Neuron 25, 345-357). We have measured axon extension on L1, laminin and the neutral substrate poly-D-lysine (PDL) with and without NGF. Both laminin and L1 support axon growth in the absence of neurotrophic stimulation in comparison to PDL. As previously reported many neurons plated on L1 exhibited growth cones with complex morphology compared to laminin. Mean axon length on the two substrates was similar at 48 hours (approx. 500μm). Concentrations of L1 between 150 and 600 ng/ml produced the ...

The axon initial segment (AIS) is the site of action potential generation and a locus of activity-dependent homeostatic plasticity. A multimeric complex of sodium channels, linked via a cytoskeletal scaffold of ankyrin G and beta IV spectrin to submembr...

The brain is a complex network of individual branching axons that ensure rapid and efficient communication between billions of connected neurons. Despite recent advancements, it remains unclear how such a highly-interconnected system optimizes the proce...

Studies of activity-driven nervous system plasticity have primarily focused on the gray matter. However, MRI-based imaging studies have shown that white matter, primarily composed of myelinated axons, can also be dynamically regulated by activity of the healthy brain. Myelination in the CNS is an ongoing process that starts around birth and continues throughout life. Myelin in the CNS is generated by oligodendrocytes and recent evidence has shown that many aspects of oligodendrocyte development and myelination can be modulated by extrinsic signals including neuronal activity. Because modulation of myelin can, in turn, affect several aspects of conduction, the concept has emerged that activity-regulated myelination represents an important form of nervous system plasticity. Here we review our increasing understanding of how neuronal activity regulates oligodendrocytes and myelinated axons in vivo , with a focus on the timing of relevant processes. We highlight the observations that neuronal activity can rapi...

Contusive spinal cord injuries (SCI) from following traumatic injury cause extensive damage to the spinal cord, which result in the loss of lower limb function. Unfortunately, long projecting supraspinal neurons, like the corticospinal tract (CST), fail...

Computational models of large myelinated somatic axons have been well characterized. However, the vagus nerve is primarily comprised of unmyelinated C-fiber axons, and the responses of small unmyelinated autonomic axons to stimulation have not been mode...