Familiarity Gates Socially Transmitted Aggression via the Medial Amygdala

Area of Science:

• Neuroscience
• Behavioral Science
• Social Psychology

Background:

• Aggression can be learned through observation, posing social risks.
• Understanding the environmental and neural factors of observationally acquired aggression is crucial.

Purpose of the Study:

• To investigate the role of social familiarity in the observational learning of aggression.
• To identify the neural mechanisms underlying socially transmitted aggression (STA).

Main Methods:

• Developed a novel "socially transmitted aggression (STA)" behavioral paradigm in mice.
• Used fiber photometry to monitor neural activity in the medial amygdala (MeApv).
• Employed chemogenetics and optogenetics to manipulate MeApv neuron activity.

Main Results:

• Male mice showed increased aggression only after observing familiar demonstrators.
• Excitatory neurons in the posterior-ventral medial amygdala (MeApv) were selectively activated during familiar demonstrator attacks.
• Inhibiting MeApv neurons suppressed STA, while activating them promoted aggression.

Conclusions:

• Social familiarity is essential for the observational transmission of aggression.
• Excitatory MeApv neurons are critical mediators of socially transmitted aggression.
• Findings suggest potential clinical intervention points for aggression.