Differential entrainment of a social rhythm in adolescent mice

Jules B. Panksepp, Jenny C. Wong, Bruce C. Kennedy, Garet P. Lahvis

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

Daily routines in animal activities range from sleep-wake cycles, to foraging bouts, to social interactions. Among animals living within groups, it is unclear whether the motivations that underlie social interactions respond to daily light-dark (LD) cycles or endogenous circadian rhythms. Employing two mouse strains (BALB/cJ [BALB] and C57BL/6J [B6]) with genetically based differences in social affect and circadian rhythms, we examined how social investigation (SI) is modulated by social deprivation and circadian factors. We found a genetic influence on SI that was moderated by the preceding duration of social deprivation, requiring 3-6 h of social isolation prior to testing. Following 6 h of social deprivation, the SI responses of adolescent B6 mice were greater than those of BALB mice only when the isolation period was imposed during the dark phase of the LD cycle. When B6 mice were weaned into conditions of constant darkness, a novel, endogenous social rhythm emerged, which was characterized by two pronounced peaks of social responsiveness (relative to one peak under LD entrainment) that were separated by 12-h intervals. Irrespective of the lighting conditions during social isolation, the SI responses of adolescent BALB mice did not oscillate across the day. Similar strain-dependent patterns of sociability were evident within groups of mice that were left undisturbed in their home cage under LD entrainment or constant darkness. Overall, genetic influences on the social phenotypes of adolescent mice are thus moderated by an interaction between social deprivation and oscillations of an endogenous social rhythm that entrains to the LD cycle.

Original languageEnglish (US)
Pages (from-to)239-245
Number of pages7
JournalBehavioural Brain Research
Volume195
Issue number2
DOIs
StatePublished - Dec 22 2008

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Keywords

  • Behavior
  • Chronobiology
  • Circadian biology
  • Circadian rhythm
  • Mus musculus
  • Social motivation
  • Social neuroscience

ASJC Scopus subject areas

  • Behavioral Neuroscience

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