Here is a recent NIH article on MB

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2765788/

conclusion

This study provides the first demonstration of the anatomical, metabolic and behavioral neuroprotective effects of methylene blue in the striatum in vivo. Co-administration of MB provided effective protection against striatal structural damage and oxidative stress. MB also improved brain metabolic activity and some features of behavioral impairment elicited by infusion of the mitochondrial toxin Rot in the striatum. Further testing of MB is indicated to help determine its potential value as an effective neuroprotective intervention in clinical conditions associated with oxidative damage and energetic failure.