Investigation of food retrieval behavior in rats

I.V. Ermakova

Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia

A new model of studying of the food retrieval behavior (FRB) in normal rats and in rats with disturbed functions (e.g. olfaction and alimentary motivation) is suggested. Four small boxes like matchboxes (6 x 4 x 1 cm) are attached at the corners of the chamber (30 x 40 cm). A pellet is hidden randomly in one of these boxes. To be opened easily, all boxes are opened slightly (0.5 cm). The rats are food deprived for one day in their home cages before trials. The rat is placed into the chamber and is taken out after the finding of the food. Maximum time of staying in chamber is 10 min. For studying of FRB the following parameters are computed: 1) time of the food search till the moment of the taking out of the pellet; 2) the number of false attempts (when the rats open empty boxes); 3) unsuccessful searches (if the rats don't find the pellets in 10 min); 4) number of approaches to the boxes. The behavior of rats during search food period (grooming, rearing, freezing, etc.) can be investigated too.

In our experiments this model was used for studying FRB in rats with the lesioned amygdala and neurotransplantation (Ermakova et al., 1984, 1989; Ermakova, 1987, 1999). In one of our researches FRB was investigated during the first 30-40 days (10 trials) following the electrolytical destruction of the basolateral part of amygdala and the transplantation of the embryonic tissue into the lesioned region (Ermakova et al., 1989, 1990). A sampling experiment was carried out prior to the surgery. Only rats that found the food during 5 min were selected for experiments. Selected animals then were divided into groups, taking the time of food search in the sampling experiments into account.

The average amount of search time was 120-180 s. FRB of the operated rats was compared with the same of intact animals. The average value of the search food time in 10 experiments was significantly greater in the group with the lesioned amygdala (325 s) than in the group of transplanted rats (38 s) and in intact animals (40 s). This model has some modifications. For example using the model it is possible to study also cognitive functions (learning, memory, cognition, etc.) in rats, putting the pellet into the boxes in the special order, but not randomly.


Poster presented at Measuring Behavior 2000, 3rd International Conference on Methods and Techniques in Behavioral Research, 15-18 August 2000, Nijmegen, The Netherlands

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