Just as humans feel frustrated or aggressive when they are maliciously directed by others or receive some kind of provocation (social provocation), when male mice are provoked by rival individuals, their aggressive behavior is more intense than usual. I know it will be.In this way, research groups at the University of Tsukuba, Keio University, and Tohoku University have clarified the mechanism in the brain when social provocation increases aggression.
The group has previously shown that when social provocation increases aggression in mice, the input of the excitatory neurotransmitter glutamate increases in the dorsal raphe nucleus in the brain.Glutamic acid is input to the dorsal raphe nucleus from various brain regions. This time, nerve projection from the lateral habenular nucleus to the dorsal raphe nucleus, which is involved in discomfort and stress (LHb-DRN projection neuron). ) Found that it was activated when the offensive behavior became intense due to social provocation.
It was confirmed that when the neural activity of LHb-DRN projection neurons was artificially activated, the aggressive behavior of male mice increased more than usual, and conversely, when the neural activity of LHb-DRN projection neurons was suppressed, it was social. It was found that the attack behavior decreased to the normal level even if it was provoked.From the above, it is suggested that LHb-DRN projection neurons are involved in the increase in aggressive behavior due to social provocation.
Furthermore, among the neurons present in the dorsal raphe nuclei, it was also found that the aggressive behavior is promoted when the neurons projecting to the ventral tegmental area are activated.That is, it is considered that the projection neurons from the lateral habenula activated by social provocation increase the aggressive behavior by further activating the projection neurons from the dorsal raphe nucleus to the ventral tegmental area. It is said.
This result clarifies a part of the mechanism by which aggressive behavior becomes excessive more than necessary, and may lead to an understanding of the problem of human violence.
Paper information:[Nature Communications] Lateral habenula glutamatergic neurons projecting to the dorsal raphe nucleus promote aggressive arousal inmice
