Alcoholism: what if we could force the brain to “forget” its addiction?

Alcoholism is a prison for those who are locked up in it. According to figures from the World Health Organization (WHO), in 2012, alcoholism was responsible for 3.3 million deaths worldwide and nearly 25% of deaths among 20-39 year olds are attributable to alcohol. Researchers at Boston University (United States) have succeeded in making the brain “forget” the reasons that pushed it to succumb to alcoholism. The results of their study were published in the journal Hippocampus.

Anxiety-inducing withdrawal

Alcohol has stress effects on the brain and on the memory system, which it can in particular fog up when a person drinks too much. When we consume alcohol, it enters the bloodstream and passes through the brain, slowing it down. By dint of drinking alcohol in excess, different regions of the brain end up adapting to this state.

When a person develops an addiction, withdrawal results in a negative affective state, where they may experience increased stress and anxiety, which likely leads them to crave and seek alcohol. This withdrawal also tends to increase negative emotions. The researchers wondered if the effects of alcoholism on the brain could be altered by manipulating memory.

“What really interests me is the intersection of memory and addiction research. Alcohol use disorders and post-traumatic stress disorder are often researched in isolation, but in the real world, the comorbidity of these two disorders is a huge public health concern. Depending on the populations taken into account, the comorbidity of alcohol-related disorders and post-traumatic stress can vary from 30 to 60%”. says Christine Cincotta, a researcher at Boston University. According to her, the two would be linked, and it would be necessary to treat the two problems together to make the negative affect coupled with alcohol disappear.

To see if they were right, Cincotta and his team studied alcohol exposure and withdrawal in mice to understand if they were able to affect their reactions to traumatic experiences. For several weeks, the mice were subjected to alcohol, in order to create an addiction in them. This dependence was accompanied for them by an abnormally high fear reaction, which the researchers learned to extinguish.

Artificially lowering anxiety and addiction

To do this, the mice were placed in a small chamber that they had never seen before. Mice are naturally curious, they will explore new environments if there is no threat. After giving them a few minutes to explore, the mice receive four light foot bumps about a minute apart. When they are frightened, the mice manifest an innate fear reaction behavior, they are “paralyzed”. Mice tend to stay in the corner of the box, hunched over and completely still.

These mice were then genetically modified to help them overcome their fear, thanks to ontogenetics. This technique makes neurons sensitive to light in order to control brain cells. The mouse cells were repeatedly activated to dampen artificial fear responses. Extinction training consisted of continually placing the mouse back into that same box. Over time, the mouse became less and less paralyzed as it refreshed its memory and will relearn that the bedroom is no longer a threatening place. Using this technique, it was possible to attenuate addictive behaviors in mice.

“Optogenetic technology as it exists today is too invasive to be used in humans, but other groups are working to develop non-invasive optogenetic toolssays Christine Cincotta. Nevertheless, the discoveries made continue to expand society’s knowledge of neural circuitry and, therefore, inform future treatments and change the way we treat patients with conditions such as post-traumatic stress disorder. and alcohol use disorders.”