Cingulate to septal circuitry facilitates the preference to affiliate with large peer groups

Area of Science:

• Neuroscience
• Behavioral Biology
• Animal Social Behavior

Background:

• Large-group living is common in animals, yet the underlying neural mechanisms remain poorly understood.
• Spiny mice (Acomys) naturally form large social groups and prefer larger congregations.

Purpose of the Study:

• To identify the neural circuitry responsible for the motivation to affiliate with large social groups.
• To investigate the role of the anterior cingulate cortex (ACC) to lateral septum (LS) circuit in group affiliation.

Main Methods:

• Identified a neural circuit (ACC-LS) responsive to group size in spiny mice.
• Utilized chemogenetics to manipulate ACC-LS circuit activity in male and female mice.
• Assessed the impact of circuit inhibition on social and nonsocial affiliative behaviors.

Main Results:

• The ACC-LS circuit showed greater activation in response to large versus small groups of peers.
• Chemogenetic activation of this circuit influenced group investigation preferences in both sexes.
• Circuit manipulation specifically affected males' preference for larger groups and impaired social, but not nonsocial, affiliation.

Conclusions:

• The ACC-LS neural circuit is essential for regulating mammalian peer group affiliation.
• This circuit plays a sex-specific role in the preference for larger social groups.
• Findings highlight a key neural basis for the evolution of complex sociality.