Wallerian DegenerationNicotinamide-Nucleotide AdenylyltransferaseSciatic NerveNerve DegenerationDemyelinating DiseasesMyelin SheathAxonsAxotomySchwann CellsSciatic NeuropathyInfarction, Anterior Cerebral ArteryPeripheral NervesNerve RegenerationNerve CrushOptic NervePyramidal TractsPeripheral Nerve InjuriesNerve Fibers, MyelinatedMice, Neurologic MutantsNeurofilament ProteinsTrauma, Nervous SystemElectrophysiological ProcessesRetinal DegenerationMacular DegenerationSpinal CordMice, Inbred C57BLSpinal Nerve RootsNerve Tissue ProteinsDiffusion Magnetic Resonance ImagingGanglia, SpinalPeripheral Nervous SystemCentral Nervous SystemDisease Models, AnimalMultiple SclerosisSpinal Cord InjuriesDemyelinating Autoimmune Diseases, CNSMotor NeuronsOligodendrogliaMicroscopy, ElectronImmunohistochemistry