Impulsivity and aggressive behavior in Roman high and low avoidance rats: Baseline differences and adolescent social stress induced changes

Caroline M. Coppens*, Sietse F. de Boer, Thierry Steimer, Jaap M. Koolhaas

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

30 Citations (Scopus)
398 Downloads (Pure)

Abstract

Adverse and stressful experiences during adolescence are often of a social nature. The social defeat model in rats is used as an animal model for bullying in humans. Usually large individual differences in response to social defeat are found. The personality type that is mostly affected and the underlying mechanisms are unknown. We used male rats of the Roman selection lines to test whether social defeat (between postnatal days 45 and 57) followed by social isolation has a different impact in animals with divergent levels of emotional reactivity and coping style. The level of offensive aggression, impulsivity and performance during frustrating non-reward (extinction) were used as measures for the adult coping style of animals. Impulsivity was measured by performance on an unpredictable operant conditioning schedule (variable interval-15, VI-15) for food reinforcement.

This study demonstrates that the adult, baseline level of impulsivity is higher in Roman high avoidance (RHA) rats. RHA rats showed a higher number of lever presses compared to Roman low avoidance (RLA) rats on a VI-15 schedule. The level of offensive aggression did not differ between the two lines. Surprisingly, a tendency towards more offensive aggression in KA rats was found.

Social stress during adolescence disturbed the normal development of adult personality, mostly in RHA rats. RHA rats that were defeated during adolescence reduced the number of lever presses on the VI-15 schedule of reinforcement and were more persistent during a session of frustrating non-reward. However, we did not find an effect of social defeat on performance during extinction. A tendency towards increased attack latencies after social defeat in adolescence was found. The time spent on offensive aggression was unaffected by social defeat. (C) 2011 Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)1156-1160
Number of pages5
JournalPhysiology & Behavior
Volume105
Issue number5
DOIs
Publication statusPublished - 20-Mar-2012

Keywords

  • Roman rats
  • Adolescence
  • Social defeat
  • Aggression
  • Operant behavior
  • Impulsivity
  • Extinction
  • MALE GOLDEN-HAMSTERS
  • AGONISTIC BEHAVIOR
  • PREFRONTAL CORTEX
  • COPING STYLES
  • RISK-FACTORS
  • WISTAR RATS
  • ANXIETY
  • DEFEAT
  • NEUROENDOCRINE
  • VULNERABILITY

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