“The old story about myelin is that it sheaths our axons pretty completely and facilitates nerve cell communication. An absence of it indicates disease, and MRI is a detection tool for this disease of demyelination, including multiple sclerosis. Except … this new research in mice showed that even normal axons are unmyelinated for long sequences and in predictable patterns for specific neuron populations. If the bright MRI signal of “white matter lesions” truly reflected a lack of myelin, even the brains of healthy people should “light up like a checkerboard.” They don’t. The four outside experts contacted for this story described the study as “landmark,” “novel,” “unexpected,” “new,” “important,” “surprising,” “stunning,” and “provocative.” The researchers who were involved in the work were just as surprised and initially skeptical about their own results. This finding is important to the multiple sclerosis community because if absent myelin is common to everyone, then the signals on MRIs that indicate ‘demyelination’ and occur in people with MS must signal something more specific. One possibility is inflammation of the sheath, an implication that has consequences for therapies.”
