The brain is the most complex structure in the universe. Over the past decade, advances in neuroscience, such as molecular genetics and imaging technology, mean that our deepest thoughts and behaviour can be analysed. Soon, designer "psychotropics" - drugs that make profound changes to our mind and personalities - could be at our fingertips. Could we be heading towards a future in which social problems are neglected in favour of fixing our brains? Sue Nelson talks to one of Britain's leading neuroscientists, Professor Steven Rose about the ethical dilemmas surrounding the future of the human brain. Producer Michelle Martin