Figure 5.

Homebase choice in the open field and novel tank diving test. (A,B) Parameters used to determine homebase choice are time spent in a zone, frequency of visits to a zone and distance moved in a zone. (A) Example of two fish in the open field test and (B) novel tank diving test. (C,D) Percentages of homebase choice. (E,F) Summary scheme of homebase behavior in the open field (E) and novel tank diving test (F). (A,B) Homebase behavior was determined on the top three scores for three different parameters: Time spent (%) in a zone, frequency of visits to that zone and distance moved in that zone. If a zone has the highest score for all three parameters, it is considered a homebase. The heatmaps show the time spent in a certain zone, and the homebase is indicated with a red rectangle. Yellow arrows indicate the hotspots in the heatmaps, which are located in the homebase. (C) Percentage homebase choice in the open field test, note that upon aging, the 3-zone homebase is much less frequent, while the 1-zone homebase is much more frequent. (D) Percentage homebase choice in the novel tank diving test. (E,F) Each homebase is indicated as a dot where the color corresponds to the fish’s age. Often, a 3-zone homebase was established (indicated as dots on the outer border, meaning that they use the three zones on that side of the tank as a homebase). Both tanks were divided into nine zones (S1–S9). The figures on the colored dots indicate the number of animals of that age that have their homebase on that location. When a dot is placed on a line between two zones, it means that the fish has a 2-zone homebase. A dot in the corner of the 3 zones indicates an L-shaped homebase.