Evidence that the behaviors in the Mouse Defense Test Battery relate to different emotional states: a factor analytic study

The Mouse Defense Test Battery (MDTB) has been designed to investigate defensive responses of Swiss-Webster mice confronted with a natural threat, a rat. These behaviors include flight, avoidance, defensive threat/attack reactions, and risk assessment activities. In the present study, a factor analysis was used to examine potential relationships between these behavioral responses. Five independent Factors were extracted from the 17 parameters obtained in the MDTB. Both Factor 1 and Factor 2 include cognitive aspects of defensive behaviors that appear to be related to the process of acquiring and analyzing information in the presence of threatful stimuli (i.e., risk assessment). Flight/avoidance responses heavily loaded on Factor 3 and to a lesser extent on Factor 4. Several defensive threat/attack reactions (i.e., upright postures and biting) highly loaded on Factor 4 and biting also loaded on Factor 3. Finally, the variables that loaded highly on Factor 5 were the number of wall rearings and climbings following the removal of the rat and the immobility time when the subject was trapped in a straight alley. Although the meaning of this latter Factor is not clear at present. Factors 1 to 4 seemingly relate to anxiety. Taken together with recent drug findings from the MDTB, the present analysis further supports the idea that this model provides measures that reflect different aspects of anxiety.