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This study was undertaken to investigate whether, in rat interactive activities, recurring sequences of behavioural events might be identified and how and to what extent each component of the pair is involved. To this aim, the multivariate temporal-pattern (t-pattern) analysis was applied to the social interactions of 9 pairs of male Wistar rats tested in open field. Interactive activities were classified into intra- and inter-subjects. Quantitative evaluations showed that intra-subject behavioural elements represented 62.37% and inter-subject ones 37.63% of the comprehensive behaviour. T-pattern analysis revealed the presence of 221 different t-patterns organized in four different categories: containing exclusively inter-subject elements; containing both inter- and intra-subject elements; consisting of rat 1 and rat 2 intra-subject elements and, finally, consisting of intra-subject elements carried out by one of the two subjects. Results show that the activity of two interacting Wistar rats is structured on the basis of several recurring temporal sequences. Moreover, social interactions appear to be expressed also by t-patterns where the behavioural elements are carried out by animals seemingly not interacting. A support of t-pattern analysis to studies on Autism Spectrum Disorders is proposed.

Aim of present research was to assess, by means of descriptive and multivariate approaches, in Wistar rats tested in hole-board apparatus, whether a microstructure of hole exploratory behavior may be identified in the behavioral response to anxiety. Two groups of 15 subjects were tested: one received 1 ml of saline IP and one was IP injected with diazepam at 0.5 mg/kg dissolved in 1 ml of saline. Following saline, six not yet reported hole-exploratory components were identified: active-dip, static-dip, rapid-dip, circular-sniff, point-sniff and central-sniff. Diazepam provoked significant changes of their per cent distribution. Results of multivariate analyses revealed a complex microstructure of hole-exploratory elements characterized by behavioral flows between sniffing and dipping patterns. Diazepam significantly modified several patternings, mainly those involving point-sniff and static dip. Hence, the hypothesis of an important role of such behavioural elements and of their patternings, in anxiety-related hole-exploratory behavior, can be proposed. It is suggested that modifications of point-sniff and static-dip patternings could evidence even subtle changes of animal anxiety condition.