JUL 28, 2017 08:09 AM PDT

Researchers Discover a Toggle Switch for Aggression in Male Mice

Researchers from the Stanford University School of Medicine have pinpointed a particular cluster of approximately 5,000 nerve cells within a mouse’s brain that invoke territorial-based male aggression when activated. They've published the results of their study in the journal Neuron.

Male mice can be territorial, but certain aspects have an impact on these mechanisms, researchers found.

Image Credit: Alexas_Fotos/Pixabay

Compared to the high number of neurons (80 million or more) that exist in a typical male mouse’s brain, 5,000 isn’t a significant number. Nevertheless, they appear to have a large influence on a male mouse’s behavior.

When activated, the male mouse would behave in aggressive ways that are unheard of in the species, like attacking female mice, going after other animal species, and even becoming enraged after seeing itself in a mirror. What this told the researchers was that male mice could be manipulated to attack just about anything by exploiting this small nerve cell cluster.

Interestingly, this aggression could be overridden by a secondary component: judgment based on past life experiences.

Related: Octopuses change color when they are feeling aggressive

Male mice that are accustomed to solitary confinement, such as those kept as lone pets in cages, are significantly more territorial than those used to sharing an enclosure with other males. With that in mind, researchers saw more success invoking rage in the former rather than the latter.

Male mice that lived in solitude their entire lives had their nerve cells toggled for aggression and would lash out at unknown threats whether they were met with an intruder on their territory or were the ones doing the intruding on another male mouse’s territory.

On the other hand, male mice that were used to living alongside others only ever lashed out when the male mouse intruded on their territory, and never when they were the ones doing the intruding.

This clear distinction indicates that pheromones, the natural mechanisms that tip the creatures off to the presence of other males and lead to heightened alertness, and the aggression that ensues, can be influenced by a mouse’s previous social interactions.

“Nature versus nurture is a false dichotomy,” said Nairo Shah, the senior author of the study.

“We’ve showed, on the one hand, that genetically programmed circuitry massively influences mammalian behavior. And we’ve seen that, under certain circumstances, nurture wins: Your social conditions can override your natural impulse to fight.”

Related: These 3D-printed mouse ovaries are fully-functional

The research brings some solid findings to the table that could help us better understand male aggression in other mammalian species; not just mice. In fact, it may even help us better understand explosive outbursts of anger in humans.

More research is needed to understand how these systems work in their entirety. Nevertheless, these findings could open new doors to treating aggression.

Source: Stanford University

About the Author
  • Fascinated by scientific discoveries and media, Anthony found his way here at LabRoots, where he would be able to dabble in the two. Anthony is a technology junkie that has vast experience in computer systems and automobile mechanics, as opposite as those sound.
You May Also Like
AUG 26, 2018
Plants & Animals
AUG 26, 2018
These Are the Most Extreme Babies in the Animal Kingdom
Think you had it hard as a baby? Ha! Think again. Human babies have it easy compared to some of the animal kingdom’s most extreme. Barnacle goose hat...
AUG 28, 2018
Plants & Animals
AUG 28, 2018
Migrating Monarch Butterflies Are Experiencing Elevated Parasitism Risks
Monarch butterflies don’t take too kindly to the colder Winter months. The insects naturally avoid the cold by migrating to places that stay warm yea...
AUG 29, 2018
Plants & Animals
AUG 29, 2018
Current Animal Conservation Efforts Skip Over Key Habitats, Study Finds
When it comes to animal conservation, opinions vary from one person to the next concerning how to go about it. But a new study published this week in the j...
SEP 10, 2018
Plants & Animals
SEP 10, 2018
Does the Weather Impact Your Likelihood of Being Bitten by a Rattlesnake?
Venomous snakes, especially rattlesnakes, sport a somewhat salty reputation for biting humans when threatened in their natural habitat. Another frequently-...
SEP 28, 2018
Genetics & Genomics
SEP 28, 2018
How Genes Changed in Domesticated Foxes
Over fifty years ago, scientists in Russia began to selectively breed silver foxes to replicate domestication....
OCT 22, 2018
Genetics & Genomics
OCT 22, 2018
Duplication Events in the Genome Drive Evolution
The majority of plants that grow in the wild and on farms have undergone some kind of duplication event in their genomes....
Loading Comments...