Tomas Deierborg is a Professor at Lund University in the south of Sweden, where he is head of the Experimental Neuroinflammation Lab. He is also head of the Department of Experimental Medical Science and a member of the strong neuroscience research environment MultiPark at Lund University, studying neurodegenerative diseases from molecules to rehabilitation. Tomas began his scientific career in the field of brain ischemia. He started to be interested in microglia in the context of neurogenesis, discovering how a stroke or a brain lesion could affect neural stem cell proliferation and differentiation by injury-activated microglia. Since then, Tomas has researched the role of microglia in several neurodegenerative diseases, including Parkinson’s and Alzheimer’s disease. Early on, he found interest in the microglia protein galectin-3, which was exclusively expressed in strongly activated microglia, e.g., close to an ischemic lesion or around a plaque in the brain of Alzheimer’s disease individuals. Using several in vitro, in vivo and clinical approaches, the role of galectin-3 has been further characterized in models of Alzheimer’s disease and discovered galectin-3 to have a detrimental role in the pathogenesis. Recently, Tomas has also studied the effect of the peripheral immune system and early life stress on the brain and its impact on the adult brain, especially in AD transgenic mice. Tomas has studied the effect of physical exercise on the brain experimentally and used a unique large cohort (Vasaloppet, the world’s biggest cross-country ski race) following individuals over two decades and how participation and race time affect the incidence of brain diseases.