MIT explained how habits are formed

Every day, almost any person performs routine operations that have long become a habit. Make coffee in the morning, brush your teeth, look out the window to check how the weather is there, check if electrical appliances are turned off before leaving the apartment. Without noticing it, we do dozens or even hundreds of similar actions.

And all of them are a sequence of smaller actions. Brushing your teeth, if you think about it, is a difficult and complex task: take a brush, take a tube of paste, squeeze the paste onto the brush, start brushing your teeth. If you think about it, then elementary actions of this kind we perform a huge amount daily. At the same time, scientists do not know too much about which parts of the brain are responsible for these actions.

Experts from the Massachusetts University of Technology were able to find out that certain neurons of the human brain are responsible for the formation of the beginning and end of the chain of routine actions. These neurons, so to speak, serve as a kind of ignition key, allowing you to perform the entire process of composite action. Neurons are activated by initiating the start of the process, then they do not manifest themselves during the whole action and are activated again when the action comes to an end.

As it turned out, this is an extremely important mechanism for performing routine actions. The research team engaged in MIT scientists led by Professor Anne Greibel. The results are published by scientists in the eighth issue of the scientific journal Current Biology.

As it turned out, a part of the brain called the striatum (lat. Corpus striatum) is responsible for the formation of a certain kind of habits in a person. This part is the anatomical structure of the end brain, belonging to the basal nuclei of the hemispheres of the brain. On the horizontal and frontal sections of the brain, the striatum has the form of alternating bands of gray matter and white matter. Several years ago, Greibel and his colleagues discovered that the work of the neurons in this part of the brain changes as soon as the habit is formed. The study was conducted not on humans, but on animals. For example, it may be a habit to make a turn to the right in a maze at the sound of a bell.

When the animal begins to study the maze, a certain group of neurons begins to work actively. But as soon as the training goes into fixing the material, the action is performed automatically, these neurons begin to work only at the very beginning of the action and at its end. By the way, once a habit is formed, it becomes extremely difficult to get rid of it - not only in terms of conscious suppression (if we are talking about a person), but also in terms of affecting neurons - they still work for a very long time, lighting the chain, like only there is an external factor known to the brain.

Previous studies conducted by the same team of researchers did not clarify why the work of specialized striatal neurons leads to the formation of habits and how this happens. In order to do this, experts trained the rats to press the levers in a certain sequence. This can be 1-2-2 or 2-1-2. In the end, the rats understood what they wanted from them and received chocolate milk as a reward for completing the assignment. In most cases, the formation of the corresponding habit took several weeks. As soon as the rats became more accurate and fast in fulfilling the task, the scientists noticed a corresponding change in the functioning of the “incendiary cells” of the brain.

And regardless of what sequence of pressing the levers were performed by the rats, the same neurons started working for them, which made it possible to understand exactly what they are responsible for starting the execution of the whole process.

Thus, it was possible to understand that the detected pattern of activity of the striatal neurons is responsible for combining small actions into one “big” action, that is, habit formation. To start the task, the “ignition” is turned on, which is then turned off for the duration of the necessary actions. By the end of the action, the neurons are switched on again, as indicated above.

In the course of the experiment, specialists managed to find out that in the course of performing a routine action, another group of neurons, known as interneurons, works. They intensified around the middle of the process. Scientists suggest that inteyrneurons can prevent animals (or humans) from performing any third-party tasks during the implementation of the main one. Now the authors of the study are conducting an additional study of the interaction of all involved groups of neurons in order to understand the whole process more deeply.