The neural circuits of mating and fighting in male mice

• Mating and aggression can be divided into appetitive and consummatory phases.
• In rodents, conspecific volatiles activate the main olfactory system to initiate approach towards a social target.
• Social investigation engages the accessory olfactory system and specifies subsequent consummatory actions.
• Hypothalamus is essential for the expression of both mating and fighting behaviors.
• Periaqueductal gray represents a key region to relay the hypothalamic signal to the spinal cord for motor execution of social behaviors.

Tinbergen proposed that instinctive behaviors can be divided into appetitive and consummatory phases. During mating and aggression, the appetitive phase contains various actions to bring an animal to a social target and the consummatory phase allows stereotyped actions to take place. Here, we summarize recent advances in elucidating the neural circuits underlying the appetitive and consummatory phases of sexual and aggressive behaviors with a focus on male mice. We outline the role of the main olfactory inputs in the initiation of social approach; the engagement of the accessory olfactory system during social investigation, and the role of the hypothalamus and its downstream pathways in orchestrating social behaviors through a suite of motor actions.