MRI Shows Low-Dose Methylene Blue Effect on Attention, Memory

Functional MR imaging shows low-dose methylene blue can regulate certain brain networks related to sustained attention and short-term memory, according to a study published in Radiology.

Researchers from the University of Texas Health Science Center in San Antonio performed a prospective, randomized, double-blinded placebo controlled clinical trial to investigate the sustained-attention and memory-enhancing neural correlates of the oral administration of methylene blue in the healthy human brain.

Twenty-six subjects ranging from 22 to 62 years old participated in the study. They all underwent functional MR imaging while performing a psychomotor vigilance task (sustained attention) and delayed match-to-sample tasks (short-term memory) before and one hour after administration of low-dose methylene blue or a placebo. Cerebrovascular reactivity effects were also measured with the carbon dioxide challenge with methylene blue versus placebo, before versus after administration

“Although the memory-enhancing effects of methylene blue were shown in rodents in the 1970s, the underlying neuronal changes in the brain responsible for memory improvement and the effects of methylene blue on short-term memory and sustained-attention tasks have not been investigated,” study author Timothy Q. Duong, PhD, said in a release. “Our team decided to conduct the first multi-modal MRI study of methylene blue in humans.”[[{"type":"media","view_mode":"media_crop","fid":"50248","attributes":{"alt":"Timothy Q. Duong, PhD","class":"media-image media-image-right","id":"media_crop_2339403341898","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"6121","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"float: right;","title":"Timothy Q. Duong, PhD","typeof":"foaf:Image"}}]]

The results showed that administration of methylene blue increased the response in the bilateral insular cortex during a psychomotor vigilance task and functional MR imaging response during a short-term memory task involving the prefrontal, parietal, and occipital cortex. 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.

“This work certainly provides a foundation for future trials of methylene blue in healthy aging, cognitive impairment, dementia and other conditions that might benefit from drug-induced memory enhancement,” Duong said.