Scientists have long believed that Alzheimer’s erases memories, but a new study has suggested that in fact they are kept in the brain but are ‘locked away’ by the disease.
This is after a team at Columbia University, USA, was able to reactivate previously lost memories in mice with dementia, using a laser-based technique.
Alzheimer’s disease affects the brain by developing proteins known as amyloid plaques and tau tangles that impair neurons, and stop them from functioning correctly and sending signals.
But experts speculated that these memories might not have been deleted altogether, and could potentially be recalled, as Ralph Martins, study author, said: “Music is the best example, which has attracted a lot of attention as a way for retrieving memories of the past in these patients – so it makes sense.”
So the team began testing their theory out on a mice model, 50% of whom were healthy and the other half had Alzheimer’s disease.
They developed a way of visualising individual memories in mice, and genetically engineered them to have neurons that glowed yellow when activated during memory storage and glowed red when activated during memory recall.
They then tested their ability to remember previously-learned information, and saw that while the healthy mice had overlap in their yellow and red, proving they were retrieving it from the same place it had been stored.
But the mice with memory loss were calling up the wrong memories from the wrong location; which might help explain why they commonly experience false memories.
They then went on to use a genetic engineering technique called optogenetics, which involves the use of blue laser light sent down a fibre optic cable into the brain to control cells, they were able to reactivate the memory in Alzheimer’s mice.
When tested again, the Alzheimer’s mice were able to remember what they had been taught.
Although this is a breakthrough, the scientists cautioned that it cannot be yet used in people, mainly because it isn’t safe or practical to tinker around with neurons and stick lasers in our brains.
And this isn’t just beneficial for those with dementia, the team claim their findings might be useful for people trying to recall crime scene events, or students recall study notes.
Alzheimer’s is the most common type of dementia, a degenerative and progressive neurological disease, affecting an estimated 850,000 people in the UK, according to the NHS.