When Mice Attack
Researchers can control aggression in mice by turning on specific neurons – but what are the implications for human rage?
“Septal rage” is a phenomenon that occurs when the lateral septum (LS) of an animal is lesioned, causing elevated levels of aggression. To find out more about how the LS controls aggression, researchers at New York University investigated the relationship between the LS and various cells in and around the ventrolateral section of the ventromedial hypothalamus (VMHvl) – a region associated with aggression in male mice (1). By stimulating specific groups of cells with a light-emitting probe, they were able to switch on or off aggressive outbursts in the animals.
“Two things surprised me about our study. The first was the clear lack of effect of the LS–VMHvl pathway in suppressing sexual behaviors, suggesting that aggression and sexual behaviors can be separately controlled,” says Dayu Lin, lead researcher and Assistant Professor in the Department of Neuroscience and Physiology at NYU. It’s surprising because, in male mice, the regions of the brain that mediate mating and aggression overlap. Lin continues, “The second surprise was how the LS modulates aggression-related cells. During aggression, the LS excites cells that are normally inhibited, as well as inhibiting cells that are normally excited.” Lin described this as a “push and pull” effect, which allows instantaneous control of aggression through a shift in this excitation–inhibition balance.
Even though septal rage isn’t found in humans, the researchers’ findings could have implications for human behavior. Lin explains, “Limited studies show that this region is defective in patients with psychiatric disorders. Our study certainly suggests that, beyond the traditional regions researchers focus on for emotional modulation (for example, prefrontal cortex), the LS could be another region to investigate.” A lot more research needs to be done on the related circuitry in humans, but this study could at least point researchers in the right direction.
- LC Wong et al., “Effective modulation of male aggression through lateral septum to medial hypothalamus projection” Current Biology, (2016). PMID: 26877081.
My fascination with science, gaming, and writing led to my studying biology at university, while simultaneously working as an online games journalist. After university, I travelled across Europe, working on a novel and developing a game, before finding my way to Texere. As Associate Editor, I’m evolving my loves of science and writing, while continuing to pursue my passion for gaming and creative writing in a personal capacity.