Jim Al-Khalili meets Cambridge University neuroscientist Barbara Sahakian.

She talks about her Life Scientific finding drugs to slow down the memory losses that happen in Alzheimer's disease.

She worked in some of the first memory clinics that were set up in the US and the UK to help people who had problems remembering and has developed tests to find out if peoples' forgetfulness is the first sign of dementia.

More recently she has turned her attention to drugs that can improve the performance of surgeons or pilots or other professions where it is important to be alert for long times.

Barbara says that they could even be used to make us more entrepreneurial. And some students are taking them as they think they could be giving them an edge in exams.

Jim and Barbara discuss the thorny ethical issues raised by these uses of these drugs.