Study: Methylene Blue Boosts Attention and Short-Term Memory
A single oral dose of methylene blue increased functional magnetic resonance imaging (fMRI) responses in regions of the brain linked to short-term memory and attention, according to a new study.
“Methylene blue was also associated with a 7% increase in correct responses during memory retrieval. The findings suggest that methylene blue can regulate certain brain networks related to sustained attention and short-term memory after a single oral low dose,” said study author Timothy Q. Duong, PhD, MRI division chief and assistant director for research at the Research Imaging Institute at the University of Texas Health Science Center at San Antonio.
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The researchers enrolled 26 subjects (age range, 22-62 years) in the prospective, randomized, double-blinded, placebo-controlled clinical trial. They performed fMRI with a psychomotor vigilance task testing sustained attention and delayed match-to-sample tasks testing short-term memory before and 1 hour after administration of low-dose methylene blue or a placebo. The investigators also measured cerebrovascular reactivity effects with the carbon dioxide challenge, in which a 2-by-2 repeated-measures analysis of variance was performed with a drug (methylene blue vs placebo) and time (before vs after administration of the drug) as factors to assess drug by time between group interactions.
Administration of methylene blue increased response in the bilateral insular cortex during a psychomotor vigilance task and fMRI response during a short-term memory task involving the prefrontal, parietal, and occipital cortex.
“Methylene blue is cheap and has been used safely to treat cyanide poisoning in the emergency room and to treat chronic methemoglobinemia,” Dr Duong said. “Thus, it could have widespread impact if its efficacy can be demonstrated on patients with memory disorders.”
Future studies should explore clinical trials to test efficacy of chronic methylene blue administration in patients with Alzheimer disease, mild cognitive impairment, and dementia, he said.
—Mike Bederka
Reference:
Rodriguez P, Zhou W, Barrett DW, et al. Multimodal randomized functional MR imaging of the effects of methylene blue in the human brain [published online June 28, 2016]. Radiology. doi: http://dx.doi.org/10.1148/radiol.2016152893.