Prof. Ami Tsari and PhD student Anna Terem from the Hebrew University found the area in the brain that is responsible for connecting an experience to the context in which the experience took place. This understanding explains the behavior patterns of people who are addicted to drugs and their renewed submission to the drug even after withdrawal
Do you remember where you were when you heard that Yitzhak Rabin was murdered?
Our brain makes a connection between significant experiences in our lives and the context in which they occurred. This mechanism also underlies drug addiction and is the reason why proximity to places or people associated with memories of drug use often causes people who have withdrawn to return to previous patterns of use. But how does this mechanism work? A new study by Prof. Ami Tzatari and PhD candidate Anna Tarem from the Edmond and Lily Safra Neuroscience Research Center and the Institute of Life Sciences at the Hebrew University, presents a relatively mysterious area of the brain, known as the claustrum, which has been found to play a significant role in creating these connections. The study was published in the prestigious scientific journal Current Biology.
The researchers' findings correspond to an idea that is already known and accepted in the research literature on the brain, which says that there are areas of the brain that participate in the connectivity between experience and reward. For example, the front of a candy store becomes very attractive to children after repeated associations with the rewarding treats inside. Over time children unconsciously learn to want to see the store, separate from the actual candy reward. Prof. Tzatari and his team actually focused the general understanding that exists in the research to a specific area of the brain. The researchers found a group of neurons within the claustrum that was activated during cocaine use. In addition, they discovered that the activity of these nerve cells is essential for the formation of the coupling between the consumption of the drug and the context in which the drug is consumed.
In order to determine when and how the claustrum participates in the experience of using a drug, the researchers "taught" laboratory mice to associate a drug with a context. The researchers gave cocaine to mice and placed them in an area with different visual elements and distinct from their normal living environment (an area with rough floor patterns and differentiated wall patterns). After several similar rounds, when the mice were given the choice of walking around in an area similar to the one associated with cocaine or in a neutral area, the mice chose to stay in the area where they had experienced the drug. If the experimenters neutralized the activity of the claustrum cells while consuming the drug, the mice no longer formed the preference to stay in the environment associated with cocaine.
Despite the distinct change in the behavior pattern of the addicted mice, the team discovered that claustrum activity is not necessary for cocaine memory retrieval. Once the mice made the association between the context and the drug, neutralization of the neurons in the claustrum did not affect their preference to be in the area with the cocaine-associated visual. "These findings increase our confidence that the claustrum participates in the link between experience and reward. The observations proved that there is a strong connection between the mouse's awareness of where it is and the experience it experiences as a result of consuming the drug," said Prof. Tsari.
"Our research has wide-ranging implications for the understanding of addiction patterns and the great importance of severing the link between location and experience before they develop," she added. "Recognizing that the claustrum plays a central role in creating the connection between context and reward, allows us to understand more about the behavior patterns of addicted people and why some of them return to using drugs even after they seem to have quit. We hope that this knowledge will lead to the development of new diagnostic tools to identify populations susceptible to addiction, as well as new therapeutic approaches."
More of the topic in Hayadan:
