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Aim of this article is to illustrate the application of a multivariate approach known as t-pattern analysis in the study of rat behavior in elevated plus maze. By means of this multivariate approach, significant relationships among behavioral events in the course of time can be described. Both quantitative and t-pattern analyses were utilized to analyze data obtained from fifteen male Wistar rats following a trial 1 - trial 2 protocol. In trial 2, in comparison with the initial exposure, mean occurrences of behavioral elements performed in protected zones of the maze showed a significant increase counterbalanced by a significant decrease of mean occurrences of behavioral elements in unprotected zones. Multivariate t-pattern analysis, in trial 1, revealed the presence of 134 t-patterns of different composition. In trial 2, the temporal structure of behavior become more simple, being present only 32 different t-patterns. Behavioral strings and stripes (i.e. graphical representation of each t-pattern onset) of all t-patterns were presented both for trial 1 and trial 2 as well. Finally, percent distributions in the three zones of the maze show a clear-cut increase of t-patterns in closed arm and a significant reduction in the remaining zones. Results show that previous experience deeply modifies the temporal structure of rat behavior in the elevated plus maze. In addition, this article, by highlighting several conceptual, methodological and illustrative aspects on the utilization of t-pattern analysis, could represent a useful background to employ such a refined approach in the study of rat behavior in elevated plus maze.

A basic tenet in the realm of modern behavioral sciences is that behavior consists of patterns in time. For this reason, investigations of behavior deal with sequences that are not easily perceivable by the unaided observer. This problem calls for improved means of detection, data handling and analysis. This review focuses on the analysis of the temporal structure of behavior carried out by means of a multivariate approach known as T-pattern analysis. Using this technique, recurring sequences of behavioral events, usually hard to detect, can be unveiled and carefully described. T-pattern analysis has been successfully applied in the study of various aspects of human or animal behavior such as behavioral modifications in neuro-psychiatric diseases, route-tracing stereotypy in mice, interaction between human subjects and animal or artificial agents, hormonal-behavioral interactions, patterns of behavior associated with emesis and, in our laboratories, exploration and anxiety-related behaviors in rodents. After describing the theory and concepts of T-pattern analysis, this review will focus on the application of the analysis to the study of the temporal characteristics of behavior in different species from rodents to human beings. This work could represent a useful background for researchers who intend to employ such a refined multivariate approach to the study of behavior., peer-reviewed

The aim of present research is to study the temporal structure of the behavior in two strains of rats with different basal level of emotionality. To this purpose, the temporal profile of the behavior in Wistar rat and in the spontaneously more anxious DA/Han strain was analyzed in the Elevated Plus Maze. Both quantitative and multivariate t-pattern analyses were carried out. In comparison with Wistar, DA/Han subjects showed a significant reduction of the permanence in open arm and a significant increase of the time spent in the central platform of the maze. Mean frequencies of each behavioral element showed significant modifications both in open and in closed arm. Multivariate t-pattern analyses demonstrated a very different temporal profile of behavior in the two strains: Wistar rats presented 197 t-patterns of different composition, whereas DA/Han rats only 26; as to the mean number of t-patterns, Wistar presented a value of 698.90, whereas DA/Han only 92.80. Similar clear-cut differences were detected for the mean number of t-patterns in the two arms and for the time course of such t-patterns. Present study has evidenced that the temporal organization of the bahavior in Elevated Plus Maze is differently structured in two strains of rats with different basal level of emotionality.

Aim of the research was to evaluate, by means of quantitative and multivariate temporal pattern analyses, the behavior of Wistar rat in elevated plus maze (EPM) test. On the basis of an ethogram encompassing 24 behavioral elements, quantitative results showed that 130.14 ± 8.01 behavioral elements occurred in central platform and in closed arms (protected zones), whereas 88.62 ± 6.04 occurred in open arms (unprotected zones). Percent distribution was characterized by a prevalence of sniffing, walking and vertical exploration. Analysis of minute-by-minute duration evidenced a decrease for time spent in open arms and central platform and an increase for time spent in closed arms. As to multivariate t-pattern analysis, 126 different temporal patterns were detected. Behavioral stripes, summarizing distribution of such t-patterns along time, showed that several t-patterns were not homogeneously distributed along the test observational period: t-patterns encompassing behavioral events occurring prevalently in central platform-open arms were observed during the first minutes, whereas t-patterns structured on the basis of events occurring mainly in central platform-closed arms were detected during the last minutes. Therefore, during the observation in elevated plus maze, rat's behavior undergoes significant rearrangements of its temporal features. Present research demonstrates, for the first time, the existence of complex and significantly timed behavioral sequences in the activity of Wistar rats tested in elevated plus maze. Application of t-pattern analysis can provide useful tools to characterize the behavioral dynamics of anxiety-related rodent behavior and differentiate the effect of various anxioselective substances.

Rationale: By means of t-pattern analysis, it has been observed that the different events, characterizing rat behavior in hole board (HB), present close interrelationships which occur sequentially and with significant constraints on the interval lengths separating them. Objectives: The aim of present research was to study, by means of descriptive and multivariate t-pattern analyses, the effects of the reference anxiolytic drug diazepam (DZP) on temporal structure of a rat’s anxiety-related behavior in HB. Methods: Fifty-six male Wistar rats were tested for 10 min in HB. Video files, collected for each animal, were coded by means of a software coder, and event log files, generated for each subject, were analyzed by means of a specific software for temporal pattern analysis (t-pattern analysis). Results: Significant diazepam-induced modifications were observed for durations of walking, climbing, edge-sniff, and face grooming. Dose-dependent decreases of t-patterns’ total amount, of their mean occurrences and of their mean length for each group were detected. Also, t-patterns’ mean occurrences, in terms of different composition, were reduced. Percent distributions showed a significant increase of t-patterns including walking for all administered groups, and significant reductions of t-patterns including climbing, immobile sniffing, and edge-sniff. Front-paw licking and face grooming were reduced at the higher DZP dose. Conclusions: Present study demonstrates, for the first time, that the temporal structure of Wistar rats’ behavioral response to anxiety in HB changes following pharmacological manipulation of anxiety condition. Moreover, t-pattern analysis is suggested to represent a useful tool to evaluate and compare different classes of anti-anxiety molecules.

The aim of present research was to analyze the temporal structure of rodent's anxiety-related behavior in hole-board apparatus (HB). Fifteen male Wistar rats were tested for 10 min. Video files, collected for each subject, were coded by means of a software coder and event log files generated for each subject. To assess temporal relationships among behavioral events, log files were processed by means of a t-pattern analysis. 14 two-element t-patterns, four t-patterns encompassing 3 events and 2 t-patterns encompassing 4 and 5 events respectively were revealed. It was demonstrated that rat behavior in HB was mainly structured on the basis of the temporal patterning among exploratory events; these ones were the most structured t-patterns detected and appeared mainly during the first 5 min of exploration, while grooming t-patterns were present prevalently after the fifth minute. Specific t-pattern parameters, such as overall occurrences and mean duration of each given t-pattern in each subject, were also studied. Present research: (a) reports for the first time that some behavioral events occur sequentially and with significant constraints on the interval lengths separating them; (b) presents the temporal flows of some behavioral elements through multimodal behavioral vectors; (c) could also be used to improve HB test reliability and its ability to detect even small induced behavioral changes.