A tiny area of the brain about the size of a sunflower seed—the bed nucleus of the stria terminalis (BNST)—can stimulate food intake in humans and mice. This is the conclusion reached by researchers at Columbia University in New York. Their work has been published in the journal Cell Reports. To study the role of this area, the team first obtained images of the brains of mice as they tasted water with five basic flavors: sweet, bitter, sour, salty, and umami (the taste of high-protein foods).

Previous studies have shown that the pleasure of sweet taste is associated with the amygdala. The scientists did indeed find neurons in it that responded only to sweet water. These cells, in turn, activated neurons in the BNST, a structure called the “extended amygdala.” This was the first direct evidence that the BNST receives taste signals.

Further experiments showed that activation of BNST neurons affects appetite. When researchers genetically modified the cells so that they would not activate when exposed to sweet water, the mice drank significantly less. Conversely, artificially activating BNST neurons caused the animals to drink more of any liquid — even bitter or tasteless ones, which they normally avoid.

It was later discovered that hungry or salt-deprived mice had significantly more BNST neurons activated when exposed to sweet or salty water compared to satiated animals. This suggests that the BNST not only responds to taste, but also integrates signals of hunger and nutrient deficiency, helping the body regulate food intake. 

According to the scientists, the new data is also important for humans: the structure of the BNST in humans is similar to that in mice. The researchers suggested that in the future, drugs that affect these neurons could help stimulate appetite in patients with severe appetite loss, such as those undergoing cancer treatment.

It was later discovered that hungry or salt-deprived mice had significantly more BNST neurons activated when exposed to sweet or salty water compared to satiated animals. This suggests that the BNST not only responds to taste, but also integrates signals of hunger and nutrient deficiency, helping the body regulate food intake.

According to the scientists, the new data is also important for humans: the structure of the BNST in humans is similar to that in mice. The researchers suggested that in the future, drugs that affect these neurons could help stimulate appetite in patients with severe appetite loss, such as those undergoing cancer treatment.