Previous to his role at Robarts, Dr. MacDonald was Chair of the Department of Physiology at the University of Toronto. There he had a research lab that investigated the cellular basis of neurological conditions such as Alzheimer's disease, schizophrenia, and stroke. Working with his colleague, Dr. Michael Tymianski he discovered that when brain cells are injured and starved of oxygen and vital nutrients, they flick a cellular switch that unleashes an outpouring of toxic chemicals that kill the surrounding cells in the following minutes and hours. According to Dr. MacDonald, it was this built-in cellular mechanism that causes more damage to the brain than the initial stroke or trauma. Dr. MacDonald received his PhD from the University of British Columbia and trained at the University of St. Andrews, McGill University, and the National Institutes of Health in Bethesda, Maryland. He was an active member of the Canadian Stroke Network, as well as a founding member of NoNO Inc., a biotechnology company that develops stroke and pain therapies.