Sunday, June 24, 2018 | ePaper

Neurons that trigger aggression in brain identified

  • Print


Life Desk :
Aggression begins in the brain and researchers linked high activity in a relatively poorly studied group of brain cells to aggressive behaviour in mice, in a new study from Karolinska Institutet, Sweden.
Using optogenetic techniques, the researchers were able to control aggression in mice by stimulating or inhibiting these cells. The results, which are published in the scientific journal Nature Neuroscience, contribute to a new understanding of the biological mechanisms behind aggressive behaviour.
'In a study exploring fundamental biological knowledge about aggressive behavior and its origins, researchers linked high activity in a relatively poorly studied group of brain cells to aggressive behaviour in mice.'
Aggression is a behaviour found throughout the animal kingdom and that shapes human lives from early schoolyard encounters to - in its most extreme expression - armed, global conflict. Like all behaviour, aggression originates in the brain. However, the identity of the neurons that are involved, and how their properties contribute to the stereotyped expression that interpersonal conflicts often manifest, remains largely a mystery.
Researchers at Karolinska Institutet now show that a previously relatively unknown group of neurons in the ventral premammillary nucleus (PMv) of the hypothalamus, an evolutionarily well-preserved part of the brain that controls many of our fundamental drives, plays a key role in initiating and organising aggressive behaviour.
Studying male mice, the researchers found that the animals that displayed aggression when a new male was placed in their home cage also had more active PMv neurons. By activating the PMv through optogenetics, whereby neurons are controlled using light, they were able to initiate aggressive behaviour in situations where animals do not normally attack, and by inhibiting the PMv, interrupt an ongoing attack.
The mapping of the PMv neurons also showed that they in turn can activate other brain regions, such as reward centres.
"That could explain why mice naturally make their way to a place where they have experienced an aggressive situation," says the study's lead author Stefanos Stagkourakis, doctoral student at the Department of Neuroscience, Karolinska Institutet. "We also found that the brief activation of the PMv cells could trigger a protracted outburst, which may explain something we all recognise - how after a quarrel has ended, the feeling of antagonism can persist for a long time."
Aggression between male mice is often ritualised and focused less on causing harm than on establishing a group hierarchy by determining the strongest member. This can be studied experimentally in the so-called tube test, wherein two mice encounter each other in a narrow corridor, from which observations can be made about submission and dominance. By inhibiting the PMv cells in a dominant male and stimulating the same cells in a submissive male, the researchers were able to invert their mutual hierarchical status.
"One of the most surprising findings in our study was that the role-switch we achieved by manipulating PMv activity during an encounter lasted up to two weeks," says study leader Christian Broberger, associate professor at the Department of Neuroscience, Karolinska Institutet.
The researchers hope that the results can contribute to new strategies for managing aggression.
"Aggressive behaviour and violence cause injury and lasting mental trauma for many people, with costly structural and economic consequences for society," says Dr Broberger. "Our study adds fundamental biological knowledge about its origins."

Source: Eurekalert

More News For this Category

Asthma risk due to traffic-related pollution

Asthma risk due to traffic-related pollution

Life Desk  :Long-term exposure to traffic-related pollution may significantly increase the risk of asthma in early childhood, a study has warned. The findings, published in the Journal of Allergy and

Vitamin D3 for your heart

Life Desk  :A treatment with Vitamin D3 might help in heart disease. Photo: CollectedAre you suffering from heart disease? A treatment with Vitamin D3 might help restore damage to your

Right amount of fluid essential while working out

Life Desk :Fluid intake is very important for a runner. Hydrate yourself before, during and after the run or else it can lead to dehydration, fatigue and can hamper performance

Past failures can boost future performance

Life Desk  :Writing a note about your past failure may you help in boosting future performance as it lower levels of stress hormone cortisol, a new study suggests. The study

Breastfeeding may reduce hypertension risk

Breastfeeding may reduce hypertension risk

Life Desk  :Breastfeeding mothers, take note! New research suggests that women who breastfeed more children and for a longer duration were less likely to suffer from hypertension after they reach

10 calcium-rich foods for bones

10 calcium-rich foods for bones

Life Desk :Our body needs calcium for healthy bones. Not only that, calcium is also very important for proper functioning of our nerves and muscles. Here are some high calcium

Marriage must follow rules

Marriage must follow rules

Rifat Zafreen :Rabeya will tie the knot today. The groom is little known to Rabeya, she got attached through face book recently. She hardly knows the detail of him and

Yoga as a way of life

Prof. Dr. Gobinda Chandra Das :This 21st the world observes International Day of Yoga, a celebration of the unity between an enlightened spirit and a healthy body. Calling for adoption

Bacteria in placenta responsible for preterm births

Life Desk :Scientists have found a higher number of pathogenic bacteria in placentas from women who delivered prematurely, supporting the presumption that maternal infection may cause preterm birth - less

Replace your mattress

Replace your mattress

Life Desk :From its immune system to proper hormonal balance, memory or emotional health, the body requires an abundant amount of comfortable sleep to function well. However, most people pay