The mice come to help an unconscious partner on the ground and do not stop getting borderline until he recovers. In science there are no absolute truths, but that three groups of scientists from three different laboratories have observed it in hundreds of mice are very close. Through a series of experiments whose results have been published in Science (Two and), the researchers verified that when a rodent was with another fallen, first he had him, then he licks him, especially his face, and, if he did not respond, he ended up nibbling his mouth and throwing him out of his tongue. The animals thus treated were recovered long before. Such behavior did not observe it if the other was active or asleep. A third work not related and published a few days ago had found that it was activated in the fallen and that the good Samaritans received a chute of oxytocin.
Help who falls or going to help someone unconscious or injured is among the most human and humanitarian behaviors there are. But it is not exclusive to humans. Among the great apes, solidarity and even altruism have been demonstrated. The long journey (and twice) with the body of its exciting breeding. Same dramatic was the finding of and not precisely by people. All this would indicate that among animals, especially the most social species, they help each other and. But also the mice?
Starting from previous observations in which they found that some mice (Homo sapiens) from their laboratory groomed colleagues who had gone through a stressful situation, researchers from the University of Southern California (United States) have conducted a series of experiments to study the behavior of rodents to another motionless on the ground, if applicable unconscious. They compared two hundred couples in different situations: the interaction with another asset, with some who slept, with other unconscious (after anesthetizing them) and a few newly deceased.
The first thing they saw is that mice interact much more with the unconscious than with assets (47.7% of the recorded time compared to 5.8%). The second is how that interaction is changing. At first they sniff both awake and anesthetized. But to the initial olisqueo (which stars almost all the time they pass by the assets), the typical mammalian lameteo followed. Thanks to high -speed cameras, they also observed another behavior: if the partner did not respond to their pampering, their actions became more energetic, with the eyes concentrated in the eyes, emels and, above all, bites in the snout. And they kept biting until they get their tongue and pull it (see photography). Before the fallen, the different mice passed 5.9% of their interaction smelling them, another 37.8% licking them and 56.3% concentrated in their snout and eyes.
For an accident, in one case, the Yacente had an object in the mouth. In addition to the tongue, the observer rodent took it out. Intriguedos, the researchers placed a polyethylene ball in a group of mice to verify that, on 80% of the occasions, they took it out. And it turns out that this worked: the mice to those who threw from the tongue and/or took the ball recovered much faster than those who had no help. The authors thought it could be due to the fact that they facilitated their breathing, but the reason would be another (see below).
In a new series of experiments, they saw that the assistants discriminated between friends and strangers. Although they did not see that their behavior was different according to the sex of the fallen, the lameteos and snacks in the snout reserved them for the mice with which they shared box.
Looking for what was behind these behaviors, the researchers were fixed in the neuronal activity of a region of the hypothalamus, which concentrates the production and release of oxytocin. This neurotransmitter and at the same time neuron favors social interaction, or capable of. They observed that the activation of these neurons tripled when a mouse was facing an unconscious. To confirm it, the scientists manipulated the release of oxytocin, blocking or forcing it. Again, they saw how it modulated the behavior until the repair against the strangers. It is told in an email the researcher of the Keck of Medicine of the Californian University and co -author of the first of the studies, Huizhong Tao: “According to our results, the activation of oxytocin neurons promoted a prosocial attitude towards strange mice.” And vice versa, by blocking the release of this hormone, they minimized their resuscifying actions even if they were cash companions.
The neurobiologist Ye Emily Wu, responsible for the University of California in Los Angeles (United States) is co -author of another work very similar to that of Tao. The WU team, led by the professor of neurobiology Li Zhang, did not anesthetized the mice, but thirsty with dexmedetomidine, an anxiolytic and sedative. In one of their evidence they put the subject in a box connected with two others, in one there was a sedated mouse and in the other one active. As in the other study, the mice always spent more time with the fallen. The other big difference is that, while the Tao group pointed to the activity in the hypothalamus, WU’s found a great activation in the tonsil, another part of the deepest brain and that, among other things, processes the olfactory signals and the pheromone system.
William Sheeran, from the University of Colorado Neuroscience Center in Boulder (United States) has not participated in these experiments, but has written a comment in. On the apparent contradiction that two different regions of the brain intervene in the same prosocial behavior, Sheeran explains it in an email: “While each group only observed a region, it is reasonable to think that these two regions could be participating together in a single circuit neuronal that is important for resuscitation behavior. ” This idea would be supported by other previous works that have shown that both the hypothalamus and the tonsil “are connected anatomically and that oxytocin shapes the processing of social information in other parts of the brain.”
The penultimate question remained, why do mice snoop, lick and throw their tongue to those who do not move? The first answer is because it works, since they regained consciousness faster. How the third work would point, published a few days ago by a different group of researchers. Like the previous two, they performed a series of similar experiments, but with them they were looking for what happened in the brain of the unconscious animal, not only in which it helped him. And they found what the previous ones did not find :. Through the use of chemiogenetic, they saw as many nerve endings of the tongue were extremes of neurons that display their action from an area of the brain stem that produces the largest amount of corenaline in the brain, key to the activation of the organism.
“When we talk about humans, it is easy to infer intentions to actions. When we talk about animals research, you have to be very cautious in attributing intentions to behaviors as a cause-effect, ”warns the Spanish neuroscientific Cristina Márquez, the main researcher at the University of Coimbra (Portugal). It is very tempting to humanize animals. That helps details of the experiments, such as those of the first study: when they found that one of the rodents took an object from the mouth to another, they replied the situation, but not only putting balls in the mouth, they also intermingled them in the anus and, in the case of females, in the vaginal area. The lifeguards or noticed them, going to which they could complicate the breathing of the other mouse.
Both Márquez, and Sheeran and the authors of the experiments reject the temptation to humanize these behaviors. “Surely there is a very simple mechanism that explains it, without the need to attribute intentions to animals to try to save the lives of others,” says the Spanish researcher, adding that “there are many examples of behaviors that seem complex that are explained by a mechanism Very simple, which is perhaps the evolutionary origin of actions that we see as very human. ” That also points Sheeran: “It is believed that innate social behaviors are preserved evolutionarily. If so, although we can see those behaviors through our various cultural contexts, that does not necessarily make the human version of the underlying neural behavior or processes are truly different from those of an elephant or a mouse. ”
The authors of the first two works also indicate to the evolution of social species. Wu, one of the authors of the second work, summarizes it like this: “Our data suggests that it is an instinctive behavior triggered by the lack of response of the congeneres, attributable to conserved and connected brain circuits”, this would produce immediate beneficial effects, As the recovery of the fallen, already long term, since they save a member of the group by increasing the possibilities of survival.
