Alzheimer's disease is becoming increasingly common as the global population ages. It is estimated that currently 44 million victims of Alzheimer's dementia exist in the world and that this will grow to more than 100 million cases by 2050. The announcement this week of the creation of the Drug Discovery Alliance - a network of labs to fast track dementia treatment aims to address the urgent need to identify drugs that prevent, slow the progression, or improve the symptoms of Alzheimer's. But what are the scientific hurdles and what's missing in our knowledge in fuelling an ambition to achieve a disease modifying therapy for dementia? Adam Rutherford speaks to Cambridge University neuroscientist Rick Livesey, and to Eric Karran, Director of Research at Alzheimer's UK

How is it possible to remember something initially and then change your account of the experience later on? Possibly, giant swathes of your own personal history are partially fictional if not completely false. The problem isn't that our memory is bad, but that we believe it isn't. Adam talks to forensic psychologist Julia Shaw whose astonishing new research examines the ability to implant completely made-up rich false memories into ordinary people in a lab setting and points to circumstances under which police officers can extract false confessions.

There's a visit to the UK's synchrotron light source at Harwell in Oxfordshire which since it started operations in 2007 has illuminating research on subjects ranging from Egyptology to virology and this year is opening its doors to the public

Adam meets Mark Kelly, one of NASA's twin astronauts taking part in a year-long space experiment to examine the impact of space travel using identical twins as subjects. With one twin orbiting on the International Space Station whilst the other remains confined to Earth, the aim is to examine how individuals with the same genetic profile respond to radically different environments - in particular the genomics of humans as they prepare to move away from their home planet.

Producer: Adrian Washbourne.