Science correspondent Malvindar Singh-Bains joins Kathryn to talk about how the human brain is the final frontier of medical research: You can replace a kidney, a lung, a liver, even a heart, but it is currently impossible to replace a sick brain. She’ll share some of her recent discoveries in Huntington’s disease and Alzheimer’s disease through studies on precious human brain tissue generously bequeathed to the Neurological Foundation of New Zealand Human Brain Bank, located within the Centre for Brain Research in the University of Auckland.