Mr Blunkett is vice-president of the Alzheimer's Society
Former Home Secretary David Blunkett has pledged to donate his brain to dementia research.
The Sheffield Labour MP is backing a £2m scheme encouraging more people to allow their brains to be used for research after they die.
Mr Blunkett is also vice-president of the Alzheimer's Society.
Dr Chris Morris, from the Brains for Dementia research brain bank at Newcastle University, said donations were vital in helping to find a cure.
He said: "Much of what we know about the brain, how it works and the treatments we currently have for dementia, comes from research on donated brain tissue.
"Brains from people without dementia are particularly important as they help us work out the difference between healthy older people and people with dementia."
Brains for Dementia, which is jointly funded by the Alzheimer's Society and Alzheimer's Research Trust, is coordinated by King's College London and has centres in Newcastle, Cardiff, London, Manchester and Oxford.
Mr Blunkett, Labour MP for Sheffield Brightside, said: "I hope to be using my brain for a good while longer yet, but I'm pleased to know that it may help people in the future when I no longer have need of it."
The society's head of research, Dr Susanne Sorensen, said it was vital to examine human brains - rather than those of animals - to enable comparisons between those of people with and without dementia.
A YouGov poll revealed that a third of 2,021 adults surveyed did not know it was possible to donate their brains.
Discworld author Sir Terry Pratchett, who as patron of the Alzheimer's Research Trust has led a high-profile campaign to increase awareness of the illness, said it was vital to encourage donations.
He told BBC Radio 5 live's breakfast show: "Research into Alzheimer's lags behind that of cancer, even though as a disease Alzheimer's costs the nation more than heart attacks, strokes and cancer put together.
"They're certainly going to have my brain because it's about time somebody made use of it."
The wife of Roland Boyes, the former MP for Houghton and Washington who died of Alzheimer's, agreed.
Pat Boyes said: "I'm donating my brain to the brain bank and I'm proud that my legacy could help researchers to make the treatment breakthrough we so urgently need."