Research that has transformed scientists’ understanding of the brain and neurodegenerative diseases like Alzheimer’s has been awarded the 2014 Newcomb Cleveland Prize of the American Association for the Advancement of Science (AAAS).

The association’s oldest honor, the prize annually recognizes the author or authors of an outstanding paper published in the journal Science, and will be awarded this year for a study that appeared in the October 2013 edition of the journal, entitled “Sleep Drives Metabolite Clearance from the Adult Brain.” The prize was presented Friday at the AAAS Annual Meeting in San Jose, Calif.

The study being honored builds on the earlier discovery by a team of researchers at the University of Rochester Medical Center (URMC) that the brain possesses its own unique waste removal system, dubbed the glymphatic system. The 2013 Science study revealed that the glymphatic system is highly active during sleep, clearing away toxins responsible for Alzheimer’s disease and other neurological disorders. Furthermore, the researchers found that during sleep the brain’s cells reduce in size, allowing waste to be removed more effectively.

This discovery may serve to explain the biological purpose of sleep by showing that the brain must devote its finite energy to either a state of wakefulness, during which time it is alert and processing information, or asleep and actively clearing waste. The URMC team has since gone on to show that the glymphatic system slows in function while we age and can become impaired after a traumatic brain injury.

“Prior to the discovery of the glymphatic system, no one really understood how the brain dealt with waste,” says Maiken Nedergaard, MD, DMSc, co-director of the URMC Center for Translational Neuromedicine and lead author of the article, in a release. “This research not only solves this mystery, but it provides us a new opportunity to re-examine and potentially treat neurodegenerative diseases, almost all of which are associated with the accumulation of cellular waste products.”

Additional authors of the study include Lulu Xie, Hongyi Kang, Qiwu Xu, Michael Chen, Yonghong Liao, Thiyagarajan Meenakshisundaram, John O’Donnell, Daniel Christensen, Takahiro Takano, and Rashid Deane with URMC, Jeffrey Iliff with Oregon Health and Science University, and Charles Nicholson with New York University.

“The awarding of the Newcomb-Cleveland Prize marks one of the highlights of the year for Science and the continuation of a tradition that is more than 90 years old,” says Marcia McNutt, editor-in-chief of the Science family of journals. “I am particularly thrilled with this year’s selection that explains why organisms require sleep: to flush waste products from the brain. The results are both startling and profound, and will likely impact neuroscience research for years to come.”

AAAS is the world’s largest general scientific society, and publisher of Science family of journals. The organization was founded in 1848, and includes more than 250 affiliated societies and academies of science, serving 10 million individuals. Science has the largest paid circulation of any peer-reviewed general science journal in the world, with an estimated total readership of 1 million.