 Illinois 2 is a cytokine that can be used to treat neurodegenerative diseases such as Alzheimer's and Parkinson's. It has been shown to reduce inflammation in the brain and improve cognition in aged mice. This study tested a brain-specific Illinois 2 delivery system to determine if it could prevent neurological decline in aging mice. The researchers found that Illinois 2 restored some of the molecular hallmarks of aging in the brain glial compartments, which improved spatial learning ability. However, Illinois 2 did not improve other aspects of cognition, such as motor skills and arousal. Overall, these findings suggest that Illinois 2 can be used to preserve cognitive function in healthy aging. This article was authored by P. L. A. Matra, Sama H. K. Tarine, A. Manuela Pasciutto, and others.