6-OHDA can be used to selectively destroy dopamine (DA) neurons and thereby produce a model for Parkinson’s disease. When 6-OHDA is administered unilaterally into the medial forebrain bundle, animals show a contralateral sensory and motor neglect that can be used as a measure of the level of degeneration and recovery. Physical exercise leads to complex and well-defined expression changes in the cortex. The forced use of the impaired forelimb after unilateral 6-OHDA lesion protects against gross behavioral impairments and causes a remarkable sparing of striatal DA and VMAT2, a marker of DA terminals (Tillerson et al., 2001). Our recent DNA microarray analysis of sham-lesioned (SH), 6-ODHA lesioned (L) and 6-OHDA lesioned + casted (LC) animals showed a robust upregulation of multiple oligodendrocyte-related transcripts in the striata of LC animals, but not in L animals (Mirnics, SFN, 2002). Transcripts for transferrin (TF), an iron-binding protein secreted in the CNS by oligodenrocytres and ependymal cells, ...