By Fattima Mahdi
New findings published in the Nature Neuroscience show that aggression and sexual behaviour are controlled by the same brain cells in male mice – but not in females. This suggests that males are more likely to exert aggression when they see a potential mate than females.
Senior investigator Dayu Lin, PhD, an assistant professor at the Neuroscience Institute at NYU Langone Health says that the brain regions that contain these cells look similar in mice and in humans. “Most research has overlooked aggression in females” Dr. Lin says. “I would say 90% of aggression studies have been done on males… we know very little about aggression in females.” She went on to say that “our study furthers our understanding of how these behaviors are organized differently in female and male mice brains.”
In 2011, Dr. Lin and her team were among the first to trace the origins of male aggression in mice to a distinct part of the hypothalamus. This brain region is responsible for regulating, temperature, thirst, hunger, sex drive, mood amongst other behaviours. The results revealed that a set of cells within this region controlled both aggressive and sexual behaviours. Lin et al. have now been able to show that the cells controlling these behaviours are separate in female mice.“The cells for aggression are close to the centre of the hypothalamus, while cells for sexual behaviour are at the edge,” says Lin. “But in the male, the cells are totally mixed up and overlap.” Dr. Lin believes that this finding could be due to the fact that aspects of mating resemble aggression for male mice. A male mice has to approach and mount a female. Whereas the female mice stays still when mating.
According to Dr. Lin, having a detailed breakdown of brain functions by gender is a “fundamental step” toward any future attempt to develop drugs that suppress extreme aggression in humans. However, according to Daphna Joel from Tel Aviv University, it is not yet clear if these findings have relevance in human behaviour. Joel says that “sexual and aggressive behaviours are complex and context-dependent in mice, and of course much more so in humans.” Joel’s own research also suggests that there is no such thing as a “female brain or a male brain.”
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