T-pattern analysis of diazepam-induced modifications on the temporal organization of rat behavioral response to anxiety in hole board

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.