A long-used drug called methylene blue may rev up activity in brain regions involved in short-term memory and attention, a small study suggests.

Methylene blue has been used in medicine for more than a century, said Dr. Timothy Duong, the senior researcher on the study and a professor at the University of Texas Health Science Center at San Antonio.

In the new study, his team found that a single dose of methylene blue improved memory test performances by 13 healthy adults in a small, placebo-based clinical trial. Based on MRI brain scans, the medication worked by stimulating brain structures involved in processing memories as well as visual and sensory information.