This can be explained by the deferential TH levels found in MCT8-deficient animals – hypothyroidism in the CNS and hyperthyroidism in the periphery (Ferrara et al., 2013; Trajkovic et al., 2007), which correlate with a decreased number of oligodendrocytes and an increased number of Schwann cells, respectively. This evidence concerns the gene TH and hypothyroidism.