Factor analysis to understand the inner structure of mouse agonistic
behavior
O.Vekovischeva1, T. Aitta-aho1, E.V. Verbitskaya2
and E.R. Korpi1
1Institute of Biomedicine/Pharmacology, University of Helsinki,
Helsinki, Finland
2Laboratory of Biomedical Statistics, Pavlov State Medical University,
St-.Petersburg, Russia
Male aggression appears a main behavioral pattern of mouse behavior and
widely involved
in pharmacological testing as a model for human psychiatric disorders.
However, a complete
interpretation of all behavior data that might suffer from subjectivity
remains problematic.
We wanted here to test a usefulness of Factor analysis that allows to
group behavioral
elements based on their space vectors and indicates causal relationship
between them,
for comparison of social behavior of Turku Aggressive (TA) with acute
form of aggression
towards an intruder and Turku Non-aggressive (TNA) mice displaying feebly
marked
agonistic behavior.
The pair encounters between TA or TNA males and group-housed unfamiliar
Swiss albino males on neutral territory were video-recorded and analyzed
subsequently using computerassisted data acquisition software (Ethograph
2.06, Ritec, St. Petersburg, Russia). Total and mean durations of the
elements as well total and relative frequencies were monitored. To compare
behavioral structures of TA and TNA males Factor analysis was used with
Equamax rotation method (SPSS 12.0.1). This is a combination of the Varimax
method, which simplifies the factors, and the Quartimax method, which
simplifies the variables.
Two main Factors were identified in behavior of TA mice based on very
emotional aggression (biting, rush and tremor) and avoidance any near
contacts with the partner (kicking, evasion, freezing). The behavior of
TNA mice contained also an aggressive patter (biting) that was related
most likely with provocation from the partner. It was accompanied by prior
exploration of the partner and demonstration of the aggressive intentions
(tail rattling, threats). Moreover, the elements which were highly associated
with the same Factor as ambivalent demonstration was, might be interpreted
similarly.
Factor analysis confirmed statistically that TA and TNA mice demonstrated
opposite coping strategies despite of presence of an aggressive pattern
in both of them. The behavioral structure of expressed aggressions was
different suggesting distinct regulative mechanisms.
Paper presented
at Measuring Behavior 2005
, 5th International Conference on Methods and Techniques
in Behavioral Research, 30 August - 2 September 2005, Wageningen, The
Netherlands.
© 2005 Noldus
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