Alzheimer's disease has long been known to completely erase memories as the condition destroys the neurons where these are stored. However, a new study found that this might not be really the case.
Researchers examined two types of genetically engineered mice--the first one healthy and the other one with a condition similar to Alzheimer's disease of humans. All had their neurons glow either yellow (when memory stage is activated) or red (for memory recall) to enable the researchers to have a visual representation of what's happening inside their brain.
To test their memory, both groups were exposed to a lemon scent while being electrically shocked. When exposed to the same lemon scent a week after, the healthy mice reacted as if it's anticipating the shock again. However, those mice with the condition reacted almost half as much as the healthy mice did.
When their hippocampi were examined, they found matching results--both red and yellow neurons of the healthy mice overlapped while the Alzheimer's mice had other type of cells glow red during recall. This means that people with Alzheimer's disease might have been retrieving memories from the wrong brain cells. Hence, can explain why they commonly "remember" false memories, Denny says.
With this at hand, they tried to reactivate the lemon-shock memory on the mice with the condition through what's called optogenetics. They exposed the brain with a blue laser to stimulate the yellow-glowing neurons to induce the freezing reaction as the mice smell the lemon scent.
This shows that people with Alzheimer's might not have actually had their memories wiped out or destroyed. Instead, the disease causes impairment that makes the recall of the memory harder.
This could be really revolutionary as “it has the potential to lead to novel drug development to help with regaining memories,” Ralph Martins at Edith Cowan University in Australia says.
However, the optogenetics technique isn't safe and practical to humans as it may cause unnecessary damage to the brain. Nonetheless, the findings show how people with Alzheimer's can still have their memories reawakened through activating the neurons involved.
What's more is that when looked at a wider perspective, the success of a possible technique for this could help even healthy and normal people retrieve memories as well. Is this a chance to "manually" forget and remember? We'll see.
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