Computerized monitoring of activity and spatial behavior is important in
different learning paradigms
R. Lohmann, O. Stiedl, J. Radulovic and J. Spiess
Department of Molecular Neuroendocrinology, Max Planck Institute of
Experimental Medicine, Göttingen, Germany
In order to analyze the activity and spatial behavior of mice during learning and
retention in different learning paradigms such as fear conditioning and object
discrimination, it is useful to apply automatic recording systems. We will demonstrate this
with two examples.
Fear conditioning
Fear conditioning is an emotional and stressful one-trial learning paradigm which has been
extensively used to study the mechanism of learning and memory and the involved brain
structures in rat and mice. Traditionally the degree of learning in this paradigm was
evaluated by only one subjectively measured behavioral parameter, freezing, which is
defined as the lack of movement besides respiration and heart beat. We have introduced two
automatically and objectively measured parameters, activity and exploration area during
training and retention, which permit a more detailed analysis of the degree of learning in
mice. Activity and exploration area are measured by a photobeam device which is positioned
around the box in which the animal is tested.
Object discrimination
The object discrimination test is a non-spatial, non-emotional and non-stressful one-trial
learning paradigm. The animal has to distinguish between a familiar and novel object. Such
evaluation has been traditionally performed by measuring frequency and duration of
exploring the objects, i.e. of directing the nose toward one of the objects in a distance
of less than 2.5 cm. Object-recognition memory was defined as the percentage of time spent
exploring the novel object as a function of the total time spent exploring both objects.
We have included automatically and objectively measured spatial parameters to have a
simpler and more detailed analysis of the discriminative ability of the animals. With a
computerized video system the distance of the animals to the objects is recorded during
the test sessions and analyzed for the following parameters:
- % time spent in the different distances to the familiar or novel object,
- % time spent close to the novel object as a function of the total time spent close
to both objects,
- frequency of visits to enter the area close to the object, and
- latency to visit the familiar or novel object.
Both examples show that automatic recording of activity and spatial parameters
significantly contribute to the detailed analysis of the behavior of the animals.
Poster presented at Measuring Behavior '98,
2nd International Conference on Methods and Techniques in Behavioral Research,
18-21 August 1998, Groningen, The Netherlands
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