Temporal patterns of rat behaviour in the central platform of the elevated plus maze. Comparative analysis between male subjects of strains with different basal levels of emotionality

- The central platform is the zone of the EPM where the rat selects the arm to explore.
- The behaviour of two strains of rats has been studied in the central platform.
- The temporal structure of rat behaviour has been analyzed through T-pattern analysis.
- Results indicate two different approaches in the interaction with the environment.

We have analyzed the temporal patterns of behaviour of male rats of the Wistar and DA/Han strains on the central platform of the elevated plus maze. The ethogram encompassed 10 behavioural elements. Durations, frequencies and latencies showed quantitative differences as to walking and sniffing activities. Wistar rats displayed significantly lower latency and significantly higher durations and frequencies of walking activities. DA/Han rats showed a significant increase of sniffing duration. In addition, DA/Han rats showed a significantly higher amount of time spent in the central platform. Multivariate T-pattern analysis revealed differences in the temporal organization of behaviour of the two rat strains. DA/Han rats showed (a) higher behavioural complexity and variability and (b) a significantly higher mean number of T-patterns than Wistar rats.Taken together, T-pattern analysis of behaviour in the centre of the elevated plus maze can noticeably improve the detection of subtle features of anxiety related behaviour. We suggest that T-pattern analysis could be used as sensitive tool to test the action of anxiolytic and anxiogenic manipulations.

Wistar and DA/Han rats are characterized by a different basal level of emotionality. The application of multivariate T-pattern analysis to study their behaviour in the central platform revealed two completely different behavioural strategies. The illustration shows the ethogram and, on the right, all the different temporal patterns detected in the two strains.261