Brain breaks down eating process into different phases

19-Sep-2024

Food intake is apparently organized at the neuronal level in a similar way to a relay race: In the course of the eating process, the baton is passed between different teams of neurons until we have finally supplied ourselves with the right amount of Energy. This is the conclusion reached by researchers at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) in a recent study. The brain presumably uses this complex mechanism to ensure that we neither eat too little nor too much. If it does not function properly, eating disorders such as anorexia or binge eating attacks may be the result.

The results appear in the Journal of Neuroscience.

In order to survive, we need to regularly supply ourselves with energy in the form of food. This process is coordinated in the hypothalamus, an important control center in the brain. It constantly receives important information from our body and our environment, such as whether it is day or night or whether our blood sugar level is currently at an all-time low. Based on this data, it then initiates certain innate behaviors - we go to bed when it's dark and to the fridge when we're hungry.

But how does the brain ensure that we don't stop eating as soon as the first craving has passed and the stretch receptors in the stomach report that food has arrived? "When we eat, we switch very quickly from a behavior that we call appetitive to a consumption behavior," says Prof. Dr. Alexey Ponomarenko, Head of the Chair of Systems Neurophysiology at the Institute of Physiology and Pathophysiology at FAU. "We know little about how the brain controls the duration of this consumption phase. It must be neither too long nor too short to ensure that we consume the correct amount of energy."

Under the leadership of Prof. Ponomarenko, the FAU team, together with colleagues from the University Hospital of Cologne, investigated what happens in the brain during the eating process. The researchers looked at the hypothalamus of mice. In principle, it is structured very similarly to that of humans. "We analyzed the electrical activity of a specific hypothalamus region using an AI method," explains mathematician Mahsa Altafi, a senior co-author of the interdisciplinary study, who also works at the Chair of Systems Neurophysiology. "This enabled us to determine which nerve cells fire, i.e. generate electrical impulses, at which times during the eating process."

Four teams of neurons active in succession

The scientist was thus able to identify four different teams of neurons that become active in succession during the eating process. The nerve cell networks therefore work together in a similar way to the runners in a relay team, which are deployed in different phases of the race. "We suspect that these teams weigh the information they receive from the body - about blood sugar levels, the amount of hunger hormones, the filling level of the stomach - differently," says Prof. Ponomarenko. The fourth team then pays more attention to the stretch sensors, for example, than the first. "In this way, the hypothalamus could ensure that we neither eat too little nor too much."

The scientists have also investigated how the neurons in the individual teams talk to each other. It has long been known that nerve cells have a rhythm of activity: There are times when they are particularly easily excitable and others when they hardly fire at all. These phases alternate regularly - often ten times a second or more. In order to communicate with each other, neurons have to vibrate in the same rhythm. It's similar to a walkie-talkie: both devices must be set to the same frequency, otherwise all you hear is static.

"We have now been able to show that the teams involved in food intake all transmit at the same frequencies," says Prof. Ponomarenko. "However, the neuronal networks responsible for other behaviors - such as exploring the environment or making contact with conspecifics - prefer to communicate on a different channel." This should make it easier for the neurons for eating behavior to exchange information and end the eating process at the right time. There may also be therapeutic potential in this finding: it is already possible to influence the rhythm of nerve cells from the outside, for example using oscillating magnetic fields. Perhaps this could be used to improve communication between the "nutrition teams". If this works, it could possibly alleviate eating disorders - at least that is the long-term hope.

"In mice, the oscillation behavior of neurons can be influenced much more directly by optogenetic manipulations," explains the FAU scientist. "In a follow-up study, we now want to investigate what effects this has on their eating behavior."

Note: This article has been translated using a computer system without human intervention. LUMITOS offers these automatic translations to present a wider range of current news. Since this article has been translated with automatic translation, it is possible that it contains errors in vocabulary, syntax or grammar. The original article in German can be found here.

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