Lasers recover memories in mice with Alzheimer’s disease

What would you give for a chance to remember lost memories? If you were suffering from Alzheimer's disease (AD), probably a lot. For some time researchers have speculated about whether the disease really destroys memories, or whether it instead might just lock them away, preventing us from recalling them. New research with mice and lasers suggests that the latter scenario might be the case.

The research team developed a technique for visualizing individual memories in the brains of mice in order to study how AD affects them. They genetically engineered mice whose neurons glowed yellow when they were storing memories, and red when they were recalling them. Two groups of these special mice were created: one was healthy, and the other was afflicted with AD.

The team observed that the AD mice were less likely to recall the correct memories when presented with stimuli. This was in line with previous human studies focusing on AD in which people with the disease would incorrectly recall where they were during the 9/11 attacks.

Observing the brains of the genetically engineered mice revealed that in the brains of the healthy mice, there was an overlap between the red and yellow neurons; the mice retrieved memories from the same place that stored them, the correct location. But in the mice with AD, the overlap was gone, meaning that the mice were recalling memories from the wrong location.

The researchers then used a technique called optogenetics, a genetic engineering technique that uses a fiberoptic laser. They shined the laser to activate the correct memories in the mice, proving that the memories still existed. Obviously researchers will need to confirm that the same process happens in humans, and then develop safe ways to use these kinds of lasers on the brain—laser-driven brain stimulation treatments—before this knowledge can be applied practically.

Still, this is fascinating information that has the potential to be applied in many ways. New Scientist points out that these techniques could help students recall their work more effectively, or help witnesses recall crime scenes and offenders more readily. This might also have the potential to help us tap into very early childhood memories, or improve our recall power in any setting substantially.

In other words, the brain training of the future might be a session of laser brain stimulation.