David Johnson, left, a KU professor in neuropsychology and aging, talks to state Rep. Mark Rhodes, R-Newton, center, about his research on Alzheimer’s and the early markers of the disease. The two were viewing teaching brains that demonstrate a normal and a diseased brain. At right are Rep. David Crum, R-Augusta, and KU research assistant RaeAnn Anderson, a junior from Circleville. State legislators toured KU’s Life Span Institute on Tuesday to experience some of the research developed at the center.