Temporal patterns analysis of rat behavior in hole-board.

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. Copyright 2009 Elsevier B.V. All rights reserved.