Autonomic function in mice during aversive emotional behavior tests
O. Stiedl1 and M. Meyer2
1Department of
Developmental and Behavioural Neurobiology and Department of Functional
Genomics, CNCR and INW, Vrije Universiteit Amsterdam, The Netherlands
2Fractal Physiology Group, Max Planck Institute for Experimental
Medicine, Göttingen, Germany
The determination of autonomic function, i.e. sympatho-vagal interaction,
has been introduced to supplement traditional behavioral measures during
fear conditioning, an emotional learning paradigm in many species including
mice. This paradigm is used to investigate the dynamics of heart rate
and blood pressure in mice in order to determine three major aspects:
- Physiological adjustments.
- Pharmacological modulation.
- Genetic approaches using mutant mice to investigate the contribution
of specific neuropeptides to physiological cardiovascular conditions.
The understanding of physiological characteristics is mandatory to draw
proper conclusions as to the effects of pharmacological interventions
on retention or expression of aversive memories. Furthermore, autonomic
measures allow for stress-free behavioral tests in the home cage of mice
when conventional behavioral parameters are unreliable. The normal heart
rate displays complex fluctuations in time in response to environmental
factors (breathing, activity, emotion), all of which are mediated by different
central and peripheral feedback loops acting in parallel over a wide range
of time scales. Measures of sympatho-vagal balance derived from non-linear
analysis of heart rate variability re.ect a highly dynamical function,
the homeodynamics of which being accessible by advanced analytical techniques.
Analysis of heart rate dynamics by techniques derived from statistical
physics facilitates a translational approach from mouse to man. The methods
are useful to uncover physiological principles and their pathological
alterations, and hence, allow for assessment of cardiac risk in both man
and mouse irrespective of species-speci.c differences in absolute heart
rate. We hypothesize that:
- Central autonomic dysregulation may contribute to elevated cardiac
risk in the absence of genuine heart disease,
- Autonomic dysregulation is potentially linked to the enhanced incidence
of adverse cardiac events observed in epidemiological studies of psychopathological
disorders in humans.
With the implementation of autonomic measures, mouse models of chronic
stress or depression will be investigated.
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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