In a 2011 published article, a team of researchers from the Hebrew University in Jerusalem was successful in erasing memories from the brain related to drug use, however, later would come 2 studies that refute the original findings. The Israeli researchers scoured through each stage from the original paper and were able to re-decipher the chain of events that lead up to the unwanted memory, along the way finding a new cognitive ability of the brain.

The initial finding and its dispute

In the original study, the researchers, led by professor Rami Yaka, were successful in developing a new method that enables the erasing of drug dependence memories from the brain. Furthermore, the team demonstrated how they were able to erase drug-related memories from lab rats, who were fed cocaine for two weeks at a certain spot in the lab (kind of like the street corner portrayed in Hollywood movies, which has become synonymous with drug trafficking).  

The researchers injected rats with a small protein, called Zeta inhibitory peptide, or better known as ZIP, straight into the prefrontal cortex into the area responsible for pleasure and reward - which has been directly linked to drug addiction. Following the compound injection, the rats were then returned to the “street corner” in the lab, where they would receive their cocaine doses, in order to monitor their behavior. Testing revealed that the rats don’t stay in one place and have stopped waiting frantically for their next fix - the finding displays that drug dependence memories have been erased from the brain. In addition, by using the same method, the research team was able to erase non-drug-related memories as well, like those of post-traumatic stress, fear, and more.

The original findings were refuted by two articles, which were published in the prestigious Nature magazine. In the refuting articles, scientists tried to recreate the Israeli experiment, by removing a target protein from the memory cells, called PKMzeta - which supposedly needed the ZIP to erase the “harmful” memory.  Nevertheless, these studies showed that it was possible to remove the memory even with the removal of the target protein, thus refuting the findings of the Hebrew University team.

“Since the two studies were published, research has halted, as no one is able to explain their findings and the fact that the process is successful even without the target protein,” said professor Yaka on the studies that refuted his own.

So what’s new?

In the new research study, which was led by professor Yaka with his research assistant Alexi Bingor, the researchers from the Hebrew University were able to re-decipher, piece by piece, the chain of events that led up to the erasing of the unwanted drug memory in rats. As part of the new research, the duo discovered a new mechanism in the brain, as well as demonstrating ZIP capabilities in erasing memories brought on by cocaine abuse - even without target protein PKMzeta, which was the highlight that refuted their first study.  

Professor Yaka explained that the team’s newly discovered brain mechanism challenges the standard approach of what was previously thought about the molecular base of memory. “Instead of looking at the bond created between the ZIP protein and receptor, we noticed that the ZIP protein is comprised of 13 amino acids -  with 5 of them are Arginine.”

According to Yaka, at the moment when the ZIP enters the cell, the Arginine dissolve and becomes free to produce 3 chemical reactions that enable the cell to continue functioning without regard to the receptor. “In other words, we realized that there is no need to focus on the target protein but rather on the Arginine, which are capable of erasing memories. A whole new world of possibilities has opened up to us, including the development of new medicine focused on addiction treatment,” explains professor Yaka.

He compares it to what the researchers knew before the new study began, the molecular base of memory is a change in electrical activity, and the ones mediating the process are ion channels, which operate as electric cables connecting the two cells, enabling transmission. The electric current is a neural conductor, which connects to the receptor at the end of the process. This enables the ions to be injected into the receiving cell, and works as a kind of doorway, facilitating information correctly into the cell.

“The process of remembering something is very [owerful and carries a high electric current flowing into the cell, which is capable of hoarding or changing memories. The whole process might change with ZIP, which delays the receptor’s activity. It’s enough to delay it for a short time in order to stop the cell from working because it is an active memory, the cell demands a continuous flow of ions to retain a memory long-term,” explains professor Yaka.

If your next thought was about the fact that erasing memory cells could affect other pleasure and reward-based memories, then lets the man behind the science, professor Yaka explain his team’s next phase after their interesting discovery: “The next stage is to erase specific memories that are related to drug addiction but leave other pleasure and reward memories intact, so only to disrupt the unwanted memories.”

Because the memory-erasing ZIP is injected directly into the brain - currently, there are alternative medicine transmission methods being tested. The team is finding simpler ways of distributing the molecules through medicine that can be swallowed and goes directly to the targeted cells in the brain that house the unwanted memory.