Stress hunger: why do we crave food?

The part of the brain responsible for stress has some nerve cells that stimulate the feeling of hunger even in its actual absence.

Often, even after a sufficient meal, we again go to the kitchen in search of food, although the feeling of hunger is already more than satisfied. And the reason here is clearly not hunger or unsatisfied appetite, but the property of certain nerve cells responsible for our behavior in moments of fear, anxiety, panic.

Scientists have studied a number of stress reactions accompanied by activation of the central gray matter of the midbrain. This is the area that is directly adjacent to the canal connecting a pair of cerebral ventricles - cavities with cerebrospinal fluid. This cerebrospinal fluid is an exchange fluid between the ventricles, the aqueduct and the spinal canal. Also in this area there are centers of nervous regulation, endowed with certain properties, such as control of pain impulses, control of social and behavioral reactions (including in extreme situations).

This area contains different groups of nerve cells that react differently to different situations. Scientists conducted experiments on rodents, using optogenetic techniques and observing the direct activity of neural structures in the brain. As a result, the researchers identified one group of nerve cells that did not cause a panic reaction at the time of stimulation, but pushed the mice to actively explore the environment. It turns out that the same neural zones demonstrated both a false hunger reaction and a desire for reconnaissance actions. Meanwhile, if a rodent found food while exploring the environment, it would certainly eat it, even despite the lack of a feeling of hunger. Preference was given to high-calorie food.

If scientists artificially blocked the work of the corresponding nerve cells, the rodents sharply limited their activity and stopped studying anything and even looking for food, despite the appearance of hunger. Although they ate, but only the food that was in close proximity to them.

Scientists analyzed the results of the experiment and once again proved the complexity of controlling eating behavior. It is not enough that the body is hungry to go in search of food: a signal from certain neural zones is necessary. At the same time, the corresponding nerve cells not only encourage the search for food, but also direct the search to more caloric food.

Despite the fact that the study was conducted on rodents, experts are confident that similar neural groups are present in humans, and their function is the same. It turns out that with active corresponding nerve cells, a person will often eat food - for example, in the form of snacks, and quite high-calorie ones. And when these structures are inhibited, "food indifference" will occur, which in the worst case can lead to anorexia. In general, the significance of the neural structures under study has not yet been fully studied: much work lies ahead, the results of which can subsequently be successfully used in the correction of eating disorders.

The results of the study were published on the page of the journal Nature