New research offers a tantalizing hope that memory loss a signature and heartbreaking symptom of Alzheimer’s disease may be reversed one day.
Scientists at the Massachusetts Institute of Technology discovered a way to retrieve old memories in mice with early Alzheimer’s symptoms.
In their experiment, described in the online journal Nature, the MIT scientists studied the ibehavior of mice that had been genetically altered to have Alzheimer’s symptoms and a group of healthy mice.
The mice were put in a chamber and given a foot shock. Retuned to the chamber an hour later, all the mice displayed fear — a sign they remembered what happened earlier. But several days later, the Alzheimer’s mice didn’t react when they were put back in the chamber, meaning that they had forgotten.
The researchers then used a technique called optogenetics to stimulate the brain. They tagged brain cells that store specific memories — in this case, the one associated with the fear fill experience with a light-sensitive protein. Then they shined light on the brain cells storing the fearful experience. The mice instantly showed signs of fear, indicating that their memory of the foot shock had been reactivated.
While optogenetics has not been used humans, the study offers hope that similar treatments maybe developed. “Even if a memory seems to be gone, it is still there,” said Susumu Tonegawa, senior author of the study.