Promising Study: Memory Retrieval In Mice With Early Alzheimer's

Promising Study: Memory retrieval in mice with early Alzheimer's
Memory retrieval is a tricky thing if diagnosed with a neurodegenerative disease like Alzheimer's.
It seems that there's new hope for Alzheimer's patients. Based on a recent study from Nature, senior author Susumu Tonegawa says that patients still have the ability to form memories. Retrieving them though is a hefty task for them.
Tonegawa and his team facilitated a study last year which involves retrieving lost memories of mice and the process of optogenetics. Their technique, optogenetics, uses light to stimulate and
In that study, Tonegawa and colleagues found they were able to retrieve the "lost" memories of these mice using a technique known as optogenetics, which involves the use of light to activate and manage neurons or brain cells. This prompted the scientists to spearhead another investigation with their recent research.
The researchers genetically modified the two kinds of mice. This would prompt them to develop beta-amyloid protein, which is responsible for plaques in the brain that cause memory loss in humans.
The researchers did an experiment with the mice. They put them in a container with healthy mice where they all got an electric shock to the foot. All of them exhibited fear.
After a few days, the normal mice still showed fear which means that they remembered the shock whereas the ones with Alzheimer's did not exhibit any fear which suggests they don't remember the shock.
The lead study author Dheeraj Roy explains, "Short-term memory seems to be normal, on the order of hours. But for long-term memory, these early Alzheimer's mice seem to be impaired."
However, upon using optogenetics, they discovered that the little creatures still had recollection of the foot shock.
The group designed the mice to release a light-delicate protein called channelrhodopsin in neurons in the hippocampus associated to fearful events. The researchers activated the engineered neurons through light. They shone the light on the mice - the creatures exhibited fear instantly.
Roy states, "Directly activating the cells that we believe are holding the memory gets them to retrieve it." He added as well, "This suggests that it is indeed an access problem to the information, not that they're unable to learn or store this memory."
The next day, when the Alzheimer's mice were returned to their containers, not one showed any fear. This means that their memories of the shock were lost. The researchers looked into the possibility of using optogenetics to retrieve memories for longer retention.
Within the span of 3 hours, the scientists shone light on the cells continually. They did this in the entorhinal cortex of the mice which is linked to the cells in the hippocampus.
After one week, the mice were put back into their chamber and they exhibited fear. This means that they remembered the shock this time, even without optogenetics.
The researchers discovered that the cells connected to the fearful memory had dendritic spines which are longer. These spines help neurons communicate with others.
The longer spines mean that the optogenetic process was effective - it enhanced the link between the hippocampus and the entorhinal cortex. In Alzheimer's, one would find that these links are damaged. The researchers discovered that the process would fail if the targeted cells area was too large. In humans, the technique should have to be well-precise. It is too risky for use in humans as it affects too much of the brain.
Tonegawa believes though that there is a chance for a better process for memory retrieval. He says, "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. Basic research as conducted in this study provides information on cell populations to be targeted, which is critical for future treatments and technologies."


Dr. David Tal has more than twenty years of clinical experience. He strongly believes that medical treatment can improve the life of Alzheimer's and memory loss patients of any age. His participation at the Age Matters Clinic allows him to share his knowledge with patients and their families.