Scientists from Germany found that expression of mice reflects their emotional state. To do this, animals have emotions strong stimuli and recorded them on video. Software video processing has allowed to identify the six expressions of the muzzle that are consistent with such basic emotions as pleasure, disgust or fear. Stimulation of brain areas associated with emotional reactions, causes a change in the muscles of the muzzle, the appropriate one of the emotions. Article published in the journal Science.
Emotion is a behavioral, hormonal and autonomic response of the body to information from the external environment, signals of your own body and cognitive processes. Emotions are adaptive function, but still we are not completely clear on the mechanism of formation of emotions in the brain. Cause-and-effect relationships in the functioning of neurons and behavioral reactions can be conveniently studied in animals — for them there are more invasive techniques the results of which are more accurate and detailed.
But what are emotions animal, are they like human and how to distinguish them? To these questions science has no clear answer. In humans and primates universal indicator of emotions is facial expressions. Perhaps in other animals, for example, in rodents, the movement of the muscles of the muzzle to reflect emotional reactions, but to the naked eye to capture the expression of the muzzle is not so easy.
German scientists led by Naicom Dolinskom (Nejc Dolensek) from the Institute of neurobiology of the max Planck Society watched the movements of the muscles of the front part of the muzzle in response to a number of stimuli. Animals electrocuted on the tail, gave them a taste of the sweet sugar or bitter quinine were injected with lithium chloride, which causes discomfort, but also provoked active and passive avoidance. The authors assumed that each of the stimuli will evoke a certain emotional response.