Hierarchy manipulation in dyads

Male or Female C57BL/6 J mice were recombined into weight-matched dyads ( ± 0.5 grams) with an unfamiliar partner at 9 weeks of age. Following 2 weeks of hierarchy formation and 1 week of hierarchy testing (via tube test), dominant or subordinate mice were recombined with a weight-matched unfamiliar mouse that was of matching hierarchy position. These new dyads were then tested for hierarchy for 1 week before being placed into stress. Animals that were initially dominant and then remained dominant following recombination were called ‘DOM-DOM’, those that started dominant and become subordinate were called ‘DOM-SUB’. Mice that were initially subordinate and remained subordinate were termed ‘SUB-SUB’, and those that were initially subordinate but become dominant were termed ‘SUB-DOM’.