Could the body's own immune system play a role in memory impairment and cognitive dysfunction associated with conditions like chronic epilepsy, Alzheimer's dementia and concussions? Researchers believe so. A new study focuses on the role of a protein known as S100B, which serves as a biomarker for brain damage. Normally, S100B is found only in the brain and spinal column. However, following a brain injury, it can leak through the blood-brain barrier into the blood.