Microstructure of rat behavioral response to anxiety in hole-board

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 behavioral 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. (C) 2010 Elsevier Ireland Ltd. All rights reserved.