title: 24-hour autonomic dysfunction and depressive behaviors in an animal model of social isolation: implications for the study of depression and cardiovascular disease.
abstract: OBJECTIVE
  To investigate the hypothesis that long-term social isolation in an animal model would produce depression-relevant behaviors and disruptions in the 24-hour autonomic and activity parameters, and to further demonstrate the utility and validity of an animal model for the study of social environment, behavior, and autonomic function. Converging evidence from both experimental and epidemiological studies indicates that there is a bidirectional association between depression and cardiovascular disease; however, the precise neurobiological mechanisms underlying this relationship are not well understood. Disruptions in the social environment may influence this relationship.
  
  
  METHODS
  Depression-relevant behaviors and ambulatory electrocardiographic and activity data were measured in 12 adult, socially monogamous prairie voles (rodents) during a period of chronic social isolation or social pairing (control conditions).
  
  
  RESULTS
  Prairie voles exposed to 4 weeks of social isolation versus control conditions (social pairing) exhibited anhedonia, increased 24-hour heart rate, reduced 24-hour heart rate variability, and predictable correlations between the behavioral measure (anhedonia) and the autonomic measures.
  
  
  CONCLUSIONS
  Social isolation is associated with depressive behaviors, 24-hour autonomic dysfunction, and predictable interrelationships between these variables in prairie voles but does not seem to be associated with rhythmicity changes in activity level or autonomic function. These findings have implications for understanding the role of the social environment in mediating the association of mood and cardiovascular disorders in humans.
authors.affiliation: Department of Psychology, Northern Illinois University, DeKalb, IL 60115, USA. angelagrippo@niu.edu
authors.forename: Angela J
authors.initials: AJ
authors.lastname: Grippo
authors.forename: C Sue
authors.initials: CS
authors.lastname: Carter
authors.forename: Neal
authors.initials: N
authors.lastname: McNeal
authors.forename: Danielle L
authors.initials: DL
authors.lastname: Chandler
authors.forename: Meagan A
authors.initials: MA
authors.lastname: Larocca
authors.forename: Suzanne L
authors.initials: SL
authors.lastname: Bates
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Porges
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000818:Animals; D001146:Arrhythmia, Sinus / Q000503:physiopathology; D003411:Arvicolinae; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001342:Autonomic Nervous System Diseases / Q000503:physiopathology; D001522:Behavior, Animal / Q000502:physiology; D002318:Cardiovascular Diseases / Q000503:physiopathology*; D002940:Circadian Rhythm / Q000502:physiology; D003866:Depressive Disorder / Q000503:physiopathology*; D004195:Disease Models, Animal; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000294:innervation / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D012934:Social Isolation