A previously unknown group of nerve cells in the brain has been shown to play a crucial role in aggressive behaviour among mothers. The study, led by researchers at Karolinska Institutet, SciLifeLab, and Stockholm University and published in Nature Communications, demonstrates that these "silent" nerve cells can be activated to influence how a mother defends her offspring.
The researchers behind the study identified a specific group of nerve cells in the mouse hypothalamus (a deep area of the mammalian brain) which are normally inactive but can be activated to induce aggressive behaviour in mice. The study was conducted using advanced optogenetic techniques, allowing the researchers to stimulate or inhibit these cells with light in order to influence their behaviour.
The results show that when these nerve cells are activated, the mice become more likely to defend their young through aggressive actions towards potential threats. The researchers were also able to demonstrate that the same cells remain inactive in mice without offspring, suggesting that motherhood alters brain function in a highly specific manner.
The study provides new understanding of how the brain regulates instinctive behaviours such as aggression and parenting and may have implications for research into neuropsychiatric conditions in which these behaviours are disrupted.
The study was led by Stefanos Stagkourakis , now Assistant Professor in Molecular Life Science at SciLifeLab and Karolinska Institutet, Department of Neuroscience , in collaboration with Christian Broberger's lab, Professor of Neurochemistry at Stockholm University.
Publication
Maternal aggression driven by the transient mobilisation of a dormant hormone-sensitive circuit.
Stagkourakis S, Williams P, Spigolon G, Khanal S, Ziegler K, Heikkinen L, Fisone G, Broberger C
Nat Commun 2025 Sep;16(1):8553
