Synaptic protection in the striatum remains robust in old (∼12 month old) homozygous <i>Wld^S</i> mice after cortical lesion.

<p>Representative electron micrographs of striatal synapses at low power (A) and higher power (B) from an old wild-type mouse (top panel) and old homozygous <i>Wld^S</i> mouse (bottom panel) 3 days after cortical lesion. Asterisks indicate degenerating synaptic profiles (identified principally by their electron dense cytoplasm) and arrows indicate healthy (i.e. non-degenerating) synaptic profiles. Degenerating synapses were readily identified in wild-type mice but rarely observed in homozygous <i>Wld^S</i> mice. As in young mice (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0015108#pone-0015108-g002" target="_blank">Figure 2</a>), the morphological appearance of degenerating synapses was indistinguishable between the different genotypes. Scale bars; A = 1 µm, B = 0.5 µm.