Memories lost through dementia may be revived, says research

A study suggests memories wiped by Alzheimer’s could be retrieved by stimulating certain brain cells using a special light.

While the memories of your loved one with dementia may fade in and out over the years, eventually they will be lost completely, and it is probably one of the most heart-breaking aspects of the disease.

However, research carried out at the Picower Institute for Learning and Memory at the Massachusetts Institute of Technology could suggest that by stimulating nerve cells in the brain, new connections could be grown which would allow the memories to return.

While the research was carried out on mice, it does raise the possibility of future treatments to reverse memory loss in the early stages of the disease.

Researchers used a technique called optogenetics, which involves using light to activate cells tagged with a photo-sensitive protein. The treatment helps neurons re-grow small buds called dentritic spines, which help to form synaptic connections between cells and ensure the ability to recall past events.

‘This is a proof of concept,’ says lead scientist Professor Susumu Tonegawa. ‘That is, even if a memory seems to be gone, it is still there. It’s a matter of how to retrieve it.

‘It’s possible that in the future some technology will be developed to activate or inactivate cells deep inside the brain, like the hippocampus or entorhinal cortex, with more precision.’

The research was published in the journal Nature and focused on memory cells in the hippocampus. They used mice that had been genetically engineered to develop Alzheimer’s-like symptoms.

Dr Doug Brown, director of research at the Alzheimer’s Society, said:

‘One of the key issues with understanding memory loss in Alzheimer’s is that we don’t know whether people are having problems storing memories or recalling them. This study in mice helps us to unpick the underlying processes and problems that lead to memory loss in the earliest stages of Alzheimer’s disease – this new evidence suggests that memory recall is the issue.

‘While interesting, the practicalities of this approach – using a special blue light to stimulate memory – means that we’re still many years away from knowing if it would be possible to restore lost memories in people.’