Selective breeding for divergence in novelty-seeking traits: heritability and enrichment in spontaneous anxiety-related behaviors

Behav Genet. 2006 Sep;36(5):697-712. doi: 10.1007/s10519-006-9058-7.


Outbred Sprague-Dawley rats can be classified as high responders (HR) or low responders (LR) based on their levels of exploratory locomotion in a novel environment. While this novelty-seeking dimension was originally related to differential vulnerability to substance abuse, behavioral, neuroendocrine and gene expression studies suggest a fundamental difference in emotional reactivity between these animals. Here, we report the first study to selectively breed rats based on this novelty-seeking dimension. Response to novelty was clearly heritable, with a > 2-fold difference in behavior seen after eight generations of selection. Three tests of anxiety-like behavior consistently showed significantly greater anxiety in LR-bred rats compared to HR-bred animals, and this difference was diminished in the open field test by administration of the anxiolytic benzodiazepine drug, chlordiazepoxide. Cross-fostering revealed that responses to novelty were largely unaffected by maternal interactions, though there was an effect on anxiety-like behavior. These selected lines will enable future research on the interplay of genetic, environmental and developmental variables in controlling drug seeking behavior, stress and emotional reactivity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Anxiety / genetics*
  • Behavior, Animal
  • Breeding / methods
  • Darkness
  • Exploratory Behavior / physiology*
  • Genetic Variation
  • Genetics, Behavioral*
  • Humans
  • Light
  • Maze Learning*
  • Motor Activity / genetics
  • Rats
  • Rats, Sprague-Dawley
  • Reproduction / genetics*