# Zone transition

Definition

This is the number of times an animal visits two or more zones in a sequence. For example, in a T-maze study, the transition Long Arm > Left Arm > Right Arm.

A Zone transition is scored when the animal enters the last zone of the sequence.

How to specify Zone transition

1.Click the Add button next to Zone transition.

2.In the Zone transition tab, to add a sequence click the Add button.

3.Select a zone and click or double-click a zone to include it in the sequence you want to define. Repeat this step to add more zones and complete the sequence.

Under Zone sequence you can view the current selection.

If the sequence is not correct, click and select the correct zones.

4.When ready click Add. Repeat steps 2-3 to add more sequences.

5.Depending on which option under Settings you select, you can get different results. See the notes below.

6.Under Threshold, enter the Zone exit threshold. That is, once the animal is detected in a zone, the animal is considered to be in the zone until its distance from the zone border exceeds that threshold. Use this option to remove false re-entries resulting from random movements of the body point around the zone border.

Click for an example.

7.Click the Body points tab, select the body point(s) you want to use for calculation.

8.Complete the procedure to add the variable. See Calculate statistics: procedure.

Zone transition counting options

For all options below, the zone transitions found in the data are marked in green. Zone transitions ignored are marked in red. The numbers in blue show the statistic Total number.

▪Allow intermediate visits to any zone

With this option the sequence ABC is found in the zone visit data ABDC, where D represents any zone defined.

In the following example, the zone sequence CAB has been defined. A total of four transitions have been found.

▪Allow intermediate visits to zones not in the sequence

With this option the sequence ABC is found in the zone visit data ABDC, just like in the example above, because D does not belong to the sequence defined. However, the same sequence ABC is not found in the zone visit data ABAC, because the second A is defined in the sequence.

In the following example, two transitions CAB have been found. The last two sequences are ignored.

▪Only count direct transitions

With this option, sequences with intermediate visits to any zone are ignored.

Do not use this option if your focal zones are not adjacent (for example, zones for a novel object and a familiar object), the arena includes multiple zone groups. In that case, direct transitions from the focal zones may not be counted if the subject crosses a third zone in another zone group. However, if your arena only includes one zone group with the non-adjacent zones, the results are reliable.

▪Include overlapping sequences

You can apply this additional option to any of the options above. Overlapping sequences may occur if the first zone of the sequence defined is visited again before the previous instance is completed. Consider the following zone visit data:

...BABAB...

When looking for the sequence BAB, two overlapping sequences BAB are found:

...BABAB...

...BABAB...

Consider the following zone visit data:

...BABABAB...

If the option Include overlapping sequences is selected, the sequence BAB is found three times.

If the same option is not selected, the sequence BAB is found two times.

However, overlapping sequences that are completed at the same time point (that is, the same zone visit) are counted as one. In the following example, the sequence CAB is defined, and the method Allow intermediate visits to any zone is used. The two sequences CAB ending at the same visit to B are scored as one. Note that transitions are scored at the end of the last zone entry.

Notes

▪The Body Points tab is only available if your experiment is set to Center-point, nose-point and tail-base detection.

▪When you visualize the Zone transition variable, only the end of the transitions (which equals the last zone entry) is marked on the time plot. EthoVision does not calculate the duration of the transition.

▪To delete a sequence, select that sequence under Settings and click the Delete button.

▪Effect of missing samples. A transition from Zone 1 to Zone 2 is also counted when the subject enters Zone 1, then it becomes missing before exiting the zone, it is found again outside Zone 1 and finally enters Zone 2.

Applications

▪In a Novel object test, calculate the number of transitions from the zone Familiar object to the zone Novel object, and from Novel object to Novel object. Or in a PhenoTyper or home cage test, calculate the transitions between the different corner visits. When the focal zones are not adjacent, select Allow intermediate zone visits.

▪For Y-maze tests, see Zone alternation.