Hunger is a hard-wired motivational state essential for survival.

American scientists clearly established, where does the signal indicating about the need of food intake come from, the Nature writes.

Agouti-related peptide (AgRP)-expressing neurons are already known to be crucial for the control of hunger.This substance acts on arcuate nucleus of the hypothalamus (ARC), where end the afferent neural pathways from the tongue and face, thus controlling the sense of hunger. During the natural or artificial simulation of this brain area, the body's need in calories is being activated, which can induce intense hunger and subsequent food intake. Nevertheless, until recently it was not known exactly where does the activation signal of agouti-related peptide come from.

Researchers conducting scientific experiments on mice with the help of modern equipment, with certainty say that the agouti-related peptide is activated by hormones produced by the paraventricular nucleus of the hypothalamus.