Professor Mackay-Sim has had along interest in regeneration and repair of the nervous system. For many years his passion has been to understand the regeneration and repair of the olfactory mucosa, the organ of the sense of smell in the nose, in which new sensory nerve cells are made throughout adult life. This is a fascinating biological question that has many direct applications to understanding human disease and repairing other parts of the nervous system. Olfactory tissue is easily accessible and provides the scientist and clinician with neural cells and the adult stem cells that give rise to them. In essence the nose provides a "window into the brain" to study cellular processes of disease and also provides adult neural stem cells with the potential to repair the nervous system. Professor Mackay-Sim and his research team are using olfactory stem cells to develop cellular models of diseases such as schizophrenia, Parkinson’s disease and motor neurone disease. They have already identified differences in nerve cell regeneration in schizophrenia and bipolar disorder that help understand how these diseases develop. Professor Mackay-Sim is scientific director of a clinical trial in which cells from the nose (called "olfactory ensheathing cells") are taken from the nose of people with paraplegia after traumatic spinal cord injury, grown in the lab, and transplanted into their own injured spinal cord. This trial provides a precedent for future trials using adult stem cells.