Characterization of social behavior in young and middle-aged ChAT-IRES-Cre mouse

Area of Science:

• Neuroscience
• Behavioral Science

Background:

• The cholinergic system modulates brain functions, including social behavior.
• Previous studies on cholinergic nicotinic receptors used mutant mice with confounding alterations.
• ChAT-IRES-Cre mice offer a specific tool to study cholinergic circuits, but their behavioral phenotype, especially social behavior and aging effects, is undercharacterized.

Purpose of the Study:

• To characterize the social behavior phenotype of ChAT-IRES-Cre mice at young and middle ages.
• To investigate the impact of aging on the cholinergic system and social behavior in these mice.

Main Methods:

• Behavioral phenotyping of ChAT-IRES-Cre mice at 2-3 months and 10-11 months.
• Assessment of gene expression for cholinergic markers (ChAT, CHT, VAChT) in the striatum.
• Evaluation of social behavior, dominance, and anxiety-like behaviors.

Main Results:

• ChAT-IRES-Cre mice exhibited decreased ChAT, CHT, and VAChT gene expression in the striatum.
• These molecular changes correlated with mild social disturbances and a tendency towards anxiety.
• Aging led to decreased social dominance, an effect not exacerbated by the observed cholinergic alterations.

Conclusions:

• ChAT-IRES-Cre mice present a valuable model for studying the cholinergic system's role in social behavior.
• The model is suitable for investigating cholinergic circuit modulation using techniques like optogenetics or DREADD.
• Aging affects social dominance independently of the specific cholinergic alterations identified in this study.