Microstructural assessment of rodent behavior in the hole-board experimental assay

The aim of the present methodological article was to assess whether a microstructure of hole-exploratory activity can be demonstrated in rats tested in the hole-board, an experimental assay widely used to study anxiety-related behaviors in rodents. Six never properly described hole exploratory behavioral components were identified: active-dip, static-dip, rapid-dip, circular-sniff, point-sniff and central-sniff. Results, assessed by means of descriptive and multivariate approaches, reveal a complex microstructural organization of these behavioral elements. The hypothesis of an important role of the relationships between point-sniff and head dipping activities, in anxiety-related hole exploratory behavior, is proposed. It is suggested that the microstructural analysis can evidence even subtle behavioral changes induced by manipulations of animal anxiety condition.