Figure 5.

Preference of experimental zebrafish towards different zones of the experimental tank during probe trial. The data are expressed as percent of time spent per unit of area of the tank. Mean ± S.E.M. are shown, sample sizes (n) equal 10 in each group. Random chance is indicated by the straight horizontal line. Two types of probe trials are administered: one set of fish are given a probe in which the red cue card is presented (cue card) and another set of fish are given a probe in which no cue card is present (during this probe trial the fish may find the location of the previous target based on extra-maze visual cues). Note the strong preference towards the location of the red cue card (target zone, indicated by the black bar) shown by fish that received paired training (upper left graph). Note that the location of the red cue card randomly changed across experimental fish and that there were no stimulus fish present in any stimulus tanks during this probe trial. Also note the strong preference toward the past fixed location of the stimulus fish (target zone indicated by the black bar) shown by fish of the paired training group during this probe trial when no stimulus fish and no red cue card are presented (upper right graph). Last, notice that the target zone induced no preference (no significant difference compared to random chance) in the not-paired training group at either probe trial (lower left and right graphs).