Memory Stimulation

Memory Stimulation

By: Christian Roque 

When it comes to memory, not many people can recall every single information that was ever presented to them. The brain is like a self-serving computer and keeps memories it thinks are important and throws out memories it doesn't think are important. Almost everyone can agree that we have memories that are beneficial to us, but we also have memories that serve no purpose to us. No matter the time span, we cannot always remember beneficial information. An article published by Scientific American explains how it can be possible to do so. 

The article states that a new study published in Nature Communications by senior author Michael Kahana found a way to electrically stimulate the brain during learning. Kahana and his team recruited 25 epilepsy patients. These patients, because of their epilepsy, already have electrodes implanted into their brains. This way, their neural electrical activity can be monitored without having to implant novel electrodes into their brains. The study found that a certain area in the brain was responsible for memory, the lateral temporal cortex. During poor learning states, this area was stimulated with an electrical signal, like a pacemaker. This is referred to as constant or "closed loop" deep-brain stimulation (DBS). 

In the same article Andres Lozano, a neurosurgeon, performed DBS on Alzheimer patients. However, he stated that closed loop DBS only works for a certain desired outcome. For memory occurring in small time frames, closed loop DBS is beneficial. For memory occurring over longer time frames, days or years, intermittent stimulation is more efficient. From Lozano's clinical trials, the results were rather astounding. Alzheimer's patients over the age of 65 showed less cognitive decline in the next year than those who did not receive DBS and also increased their brain glucose metabolism. 

These two studies are parallel to Dr. Ken Paller's study in memory and sleep. In his study, he and his team focused on what is now called Target Memory Reactivation (TMR). He and his team would teach participants something, which is accompanied by a sound, before they go to sleep. During sleep, the same sound was played in the background of white noise. After the participants woke up, they performed whatever was being taught to them and increased in their accuracy, which showed memory improvement/reactivation. Both Dr. Paller and the studies in Scientific American focus on memory activation, but they both still have much more to learn, and hopefully one day their techniques will be implemented in the near future. 

Reference: 

Smith, Dana G. "Brain 'Pacemaker' Could Help You Remember Only What You Might Forget." Scientific American, 6 Feb. 2018, www.scientificamerican.com/article/brain-ldquo-pacemaker-rdquo-could-help-you-remember-only-what-you-might-forget/#.