Rearing paradigm in a nonhuman primate affects response to beta-CCE challenge

Area of Science:

• Neuroscience
• Behavioral Science
• Primatology

Background:

• Early life experiences significantly shape adult behavior and stress responses.
• Controllability over environmental stimuli is a key factor in development.
• Benzodiazepine receptor inverse agonists, like beta-CCE, can reveal underlying behavioral predispositions.

Purpose of the Study:

• To investigate the long-term effects of early life control on behavioral responses to a pharmacological challenge.
• To determine if differential rearing conditions influence reactions to beta-CCE, a putative anxiogenic agent.
• To examine the impact of early mastery experience on aggression and anxiety-related behaviors in rhesus monkeys.

Main Methods:

• Two groups of rhesus monkeys were reared with differing levels of control over appetitive resources.
• At 18-24 months, beta-carboline-3-carboxylic acid ethyl ester (beta-CCE) was administered to assess behavioral and physiological responses.
• Behavioral changes and plasma cortisol levels were measured to evaluate drug effects and stress responses.

Main Results:

• Beta-CCE administration induced behavioral activation, primarily characterized by increased aggression, in both groups.
• Monkeys reared with early life mastery exhibited a significantly greater increase in aggression compared to yoked controls.
• Plasma cortisol levels increased in both groups, with a more pronounced elevation observed in the yoked control subjects.

Conclusions:

• Early life experience with environmental controllability has lasting effects on adult behavior.
• The capacity for control during development can modulate the behavioral response to pharmacological challenges, specifically increasing aggression.
• These findings highlight the critical role of early life mastery in shaping long-term behavioral phenotypes and stress reactivity.