Memory loss is one of the hallmarks of Alzheimer’s and heartbreaking for loved ones to watch progress. Gone are the detail; child’s wobbly first steps. The achievements of a distinguished 3o-year career. And the tall tales of traveling the globe that o rolling on the floor with laughter.
Scientists had assumed for a long time that the disease destroys how those memories are encoded and makes them disappe; what if they weren’t actually gone — just inaccessible?
A new paper published Wednesday by the Massachusetts Institute of Technology’s Nobel Prize-winning Susumu Tonegawa
strong evidence of this possibility and raises the hope of future treatments that could reverse some of the ravages of the dis€
“The important point is, this is a proof of concept,” Tonegawa said. “That is, even if a memory seems to be gone, it is still thf 1-ow to retrieve it.”
The research, described in the journal Nature, involved two groups of mice. One was a normal control and the other was ge engineered to have Alzheimer’s-like symptoms. Both groups were given a mild electric shock to their feet. The first group at remember the trauma of the incident by showing fear when placed back in the box where they had been given the shock. Th mice, on the other hand, seemed to quickly forget what happened and did not have an upset reaction to the box.
Their reaction changed dramatically when the scientists stimulated tagged cells in their brains in the hippocampus — the p- encodes short-term memories — with a special blue light. When they were put back in the box following the procedure, thei shock appeared to have returned, and they displayed the same fear as their healthy counterparts.
Tonegawa and his colleagues wrote that the treatment appears to have boosted neurons to regrow small buds called dendrit connections with other cells.
The revelations have “shattered a 20-year paradigm of how we’re thinking about the disease,” Rudy Tanzi, a Harvard neuro is not involved in the research, told the Boston Herald. He said that since the 198os, researchers believed the memories just stored properly.
The technique used in the study — optical stimulation of brain cells, or “optogenetics” — involves the insertion of a gene int, to make them sensitive to blue light and then stimulating them with the light.
By Arlene Eunjung Cha