In accordance with the lack of change of excitatory synaptic densities, there was no difference in the densities of excitatory motor neurons (using an antibody against the LIM-homeobox domain markers Islet1/2) (Fig. 1n & Online Resource Fig. 1q, r) between control and MS cortex indicating that they survive even in late progressive MS. Here, ISL1 is linked to myeloid sarcoma.