Answer
Traumatic brain injury was the focus of Luria's study on Lev Zasetsky. Zasetsky, a renowned mnemonist, suffered a severe head injury during World War II. Luria's meticulous examination of Zasetsky's cognitive abilities after the injury revealed profound changes in his memory and thinking processes. Luria's findings provided valuable insights into the brain's functional organization and the impact of brain damage on cognitive functioning.