Could the freeways or backroads you spend your life navigating make a crucial difference in your cognitive health as you age? The hippocampal formation, a region within the brain’s medial temporal lobe, is often the earliest to show degradation in Alzheimer’s disease. Most cognitively normal zones were in or near urban areas with high environmental complexity measures. “All the other measures that scientists study — like socioeconomic status, level of education, income and so on — those things are co-variates, not the factors that actually give you Alzheimer’s,” Kennedy said. “The entorhinal cortex is where this spatial cognitive ability to do allocentric navigation originates, learning to deal with environmental complexity,” Kennedy said.