Summary: Mouses, like humans, sail on social hierarchies using subtle clues, but instead of reading facial expressions or clothing, they count on chemical signals. A new study reveals that male mice can determine the social rank of unknown opponents using airborne odors and physical perfume indices.
In a tunnel confrontation test, the mice withdrew or resisted their terrain according to the way in which they evaluated the other of the mouse compared to theirs. The deactivation of olfactory and vomeronasal systems has eliminated this capacity, but eliminating only one did, showing that the systems compensate for each other.
Key facts:
- Double sensory systems: Mouses use both olfactory (airborne) and vomeronasal (contacts) indices to assess social status.
- Dynamic treatment: Social rank is not based on fixed behavior but deduced by real -time sensory integration.
- Human parallel: Like mice, humans assess the social status of unknown individuals using available sensory indices, especially in unknown social environments.
Source: Francis Crick Institute
Like many mammals, mice live in a social hierarchy where some are more dominant than others. This helps to avoid conflicts and establish breeding partners.
It was previously suggested that some mice could display fixed behavior, regardless of whom they interact, or that physical properties can give clues to the social classification.
However, new research published today in Current biology shows that mice rather deduce a rank of mice unknown by chemical signals transmitted in the air (odors) or by direct contact (non -volatile perfume signals).
The Crick team has set this using a test where male mice enter a transparent tube at the opposite ends, meeting in the middle. In this type of confrontation, a more subject animal will generally be withdrawn.
The researchers first examined interactions in mice who shared the same cage, using this to classify each mouse on a hierarchy, before observing how the mice responded to a set of unknown opponents.
They found that foreigners could recognize the rank of the other, compare it to their own and withdraw or force the other mouse to withdraw.
The team then tested the mice in the dark, noting that this did not affect recognition of the rank, suggesting that signals such as physical size or behavior do not determine the recognition of a more aggressive opponent. Likewise, casting the mice to eliminate their sex hormones had no impact.
Finally, the team has experimentally blocked the two chemiosensory systems that mice use – one for odors in the air (olfactory system) and one for chemical signals transmitted by physical contact (vomeronasal system).
They found no effect when only one of these systems has been deleted; The two had to be ablated before the mice could recognize the rank of opponents. This has shown that mice use olfactory and vomeronasal systems to recognize rank and can compensate if we are missing.
Like mice, people can also deduce the social status of others around them compared to their own, also using sensory clues, including language, facial expression or clothes.
The next step for researchers consists in studying the brain areas of information on the rank and rank of opponent owners and to make a retirement or progression decision.
Neven Borak, a former doctoral student in the neuronal treatment laboratory depending on the state in Crick and the first author, said: “We have shown that mice weighed foreigners using chemical clues and can detect social status without the need for an extensive history of confrontations with these specific adversaries. It is a fascinating phenomenon that humans make too mainly visual quotes.
“Our work offers an interesting perspective on social mobility: humans, such as mice, can enter a new group of people, but maintain understanding of social rank and assess the social status of unknown people.”
Jonny Kohl, group leader of the neuronal processing laboratory dependent on the state in Crick and principal author, said: “We have shown for the first time how mice integrate internal and external information on domination.
“This shows that a decision based on the relative ranks is taken in the brain before the mice show subjected assault or behavior, rather than fixed differences in behaviors leading to an aggressive or docile mouse.”
The neuronal treatment laboratory dependent on the state studies how brain processes are affected by the state of the body.
By studying how physiological states, such as pregnancy, stress or sleep, have an impact on neural circuits in mice, researchers hope to advance a more integrative vision of brain physiology in health and sickness.
About this news of sensory and social research in neuroscience
Author: Clare Green
Source: Francis Crick Institute
Contact: Clare Green – Francis Crick Institute
Picture: The image is credited with Neuroscience News
Original search: Open access.
“Dominance classifies inference in mice by chemiosensation” by Neven Borak et al. Current biology
Abstract
Dominance Rank Inference in mice via chemiosensation
Social dominance hierarchies allow effective allocation of resources and avoidance of conflicts in animal communities.
Individuals can determine their relative status following the results of previous conflicts, as shown by the aggression formation and the effect of winners, where successive victories increase the probability of future victories.
The repeated optogenetic stimulation of the dorsomedial prefrontal cortex (DMPFC) leads to sustainable row increases, which suggests that social rank is derived as a statistic of past results.
However, the relative rank could be evaluated more effectively by incorporating information on the status of domination of an opponent.
The signals of pheromones, like Darcin, are enriched in the urine of dominant individuals, suggesting that hierarchical behavior can integrate information on clean and opposing rank.
Although previous studies have explored learning and neuronal representation of clean rank, the way in which the rank of opponents is detected and encoded remains uncertain.
Here, we approach this question in male mice using a tube test test.
We show that stable hierarchies are not based on fixed behavioral features and that mice can deduce the rank of unknown opponents by detecting evolving chemiosensory clues.
Sensory ablation experiences reveal that olfactory and vomeronasal signals are sufficient for the assessment of ranks. Males mice thus use chemiosensory signals to deduce dominance status during social interactions.
