Guy McKhann, world-renowned brain scientist, founding director of the Johns Hopkins Department of Neurology and mentor to three generations of leaders in academic neurology around the world, died April 12 at age 91.

In 1969, when McKhann was recruited to Johns Hopkins at age 37 to establish the neurology department, hospitals rarely had separate departments focused on the brain.

McKhann built a department that consistently ranked among the best in the world. Under his leadership, Johns Hopkins teams discovered the scientific basis for many now common therapies, such as deep brain stimulation for Parkinson’s disease, the ketogenic diet for epilepsy and the use of botulinum toxin for many conditions.

His achievements also include important contributions regarding the pathogenesis and treatment of Guillain-Barre syndrome, defining the criteria for diagnosing Alzheimer’s with the “McKhann Criteria,” and studying the cognitive changes after coronary artery bypass grafting. Additionally, he established a postdoctoral training program that is considered among the country’s finest and has produced national and international leaders in the field.

After leading the neurology department for 20 years, McKhann founded and directed the Zanvyl Krieger Mind/Brain Institute at Johns Hopkins and then served as the clinical director of the National Institute of Neurological Disorders and Stroke at the National Institutes of Health.

Together with his wife, Marilyn Albert, director of the Division of Cognitive Neuroscience at Johns Hopkins, he co-authored the 2002 book Keep Your Brain Young: The Complete Guide to Physical and Emotional Health and Longevity.