Fig. 12.

Procedure for marking frames with particular attributes. In this example, frames associated with particular nose positions are marked, and then examined for abrupt changes in direction. a One frame showing positions of odor plates in the arena. b View showing nose positions before marking. c Same view during the process of marking a subset of frames near upper odor plate. d In this view, the marked frames are highlighted. e After switching to a different view, the marked frames are still highlighted. In the present example, this allows identification of frames that are both associated with particular positions and with high values of body angle changes. f Selection of one such dot reveals a frame in which the mouse is near the upper plate and the tail is mistaken for the nose (g)