[Neurochemical mechanisms of a need, motivation and goal-directed behavior]

In this review is analyzed four kinds of needs, which include both humans and animals. These are: 1--the need to eat 2--need to drink 3--sexual need and, 4--the need to enhance or prolong the positive emotional state, and conversely, the need to dispose or avoid pain and unpleasant effects or negative emotional state. The centers of the first three needs are localized in the hypothalamus. The fourth need induced by integrative processes and determined the key role of the mesolimbic dopamine (DA) system of brain. Leptin and ghrelin, a hormone of satiety and hunger form of food motivation in neurons food center of the hypothalamus interacting with DA signal. Vasopressin, antidiuretic hormone, form drinking motivation in the neurons of hypothalamus drinking center interacting with DA signal. Vasopressin, oxytocin and steroid hormones form a sexual motivation in the neurons of the sexual center of the hypothalamus interacting with DA signal. Terminals of the mesolimbic DAergic system innervate hypothalamic neurons, amygdala, habenula and nucleus accumbens. The part of the neurons of amygdala and habenula respond to positive stimuli, and the other part to the negative stimuli. Integrative structure of mesolimbic DAergic system is the nucleus accumbens. GABAergic terminals of this nucleus terminate on exterior and interior nucleus of the ventral pallidum. Describes and discusses the emotional and motivational network and their interaction on the global DAergic signal.