Knowledge Base

Cumulative Zones

Analyze two or more zones as one. The procedure below creates a cumulative zone using two or more existing zones. The original zones are not deleted; the cumulative zone is added as a new zone, outside the original zone group.

For example, in an Elevated Plus Maze test, if you have defined two open arms and two closed arms, you can define the two open arms as cumulative zone Open Arms, and the two closed arms as cumulative zone Closed Arms. You can add zones from different zone groups to a cumulative zone.

Procedure

1. In the Arenas and Zones section, click a zone group in which you want to create a cumulative zone.
2. Click the Add Cumulative Zone button at the bottom of the Arenas and Zones section.
3. In the Add Cumulative Zone window, choose one of the following options:
   • Create New Cumulative Zone: Type in the name of the new cumulative zone, click OK, and select the zones in the window that appears.
   • Use Existing Cumulative Zone: From the drop-down list, choose the name of an existing cumulative zone in another Arena Settings profile.

Duplicate a Cumulative Zone

Use the option Use Existing Cumulative Zone to replicate a cumulative zone that was defined in another Arena Settings profile and include it in a new Arena Settings. Make sure that all the zones that make up the existing cumulative zone are also defined in the new Arena Settings.

For example, in a radial-arm maze test, four zones can be either baited or not baited. In some trials zones 1 and 3 are baited; in other trials zones 2 and 4 are baited.

1. In Arena Settings 1, define all zones. Next, define a cumulative zone Baited with zones 1 and 3. You can double-click the label Cumulative Zone 1 and rename it to Baited.
2. Create a new Arena Settings (or duplicate Arena Settings 1). Make sure all relevant zones are defined.
3. Swap the labels for the zones.
4. If you created Arena Settings 2 anew, create a cumulative zone and choose Use Existing Cumulative Zone. Choose the existing cumulative zone from Arena Settings 1. If you have duplicated Arena Settings 1 to obtain Arena Settings 2, the cumulative zone is already pointing to the correct zones after you swap the labels.

Note that the same physical zone is labeled with different names in the two Arena Settings profiles; take this into account when you analyze single zones.

Important: Do not rename the cumulative zone in Arena Settings 2 when it is pointing to physical zones other than those in Arena Settings 1. If you do so, the name also changes in Arena Settings 1, which would create confusion.

Notes

• A cumulative zone is not the same as a zone group. A zone group is one of the layers in the Arena Settings, where zones are always analyzed separately. A cumulative zone is an extra zone, outside the zone group it originates from. For example, zones S2 and S3 can form Cumulative Zone 1.

Shelters and Other Hidden Zones

Hidden Zones and Entry Zones

You can define a shelter or any zone where the animal is out of view as a Hidden zone. After you have defined a hidden zone, you must define at least one Entry zone for that hidden zone. The entry zone is used to determine whether the animal has entered or left the hidden zone.

Entering a Hidden Zone

Suppose you have a square shelter defined as hidden zone and an entry zone on the side of the shelter where the animal can enter it. When the animal enters the entry zone, one or more body points are tracked in that zone. As soon as a body point is not detected anymore, that body point is assumed to have entered the hidden zone and this body point is positioned in the center of the hidden zone during the time the animal is inside the shelter.

Leaving a Hidden Zone

By default, the animal is considered to have left the shelter when it is next detected, that is, when its body points are "not missing". However, every time an animal pokes its nose out, this may be recorded as an exit. Subsequently, retracting back into the shelter without ever really leaving the shelter would count as entering again. This results in an overestimation of how often the animal enters and exits the hidden zone. Therefore, EthoVision XT versions 5.1 and up have the possibility to also use the entry zone as leaving zone. The animal is then considered to have left the hidden zone when it was first considered to be in a hidden zone, and subsequently detected outside of the entry zone.

In other words, the exit is counted only when the body point crosses the border between the entry zone and the rest of the arena. We recommend you use this function if you want to prevent an overestimation of entrances into, and exits from, the hidden zone.

If the animal's center point is first detected in the entry zone, and then disappears because the apparent size of the animal becomes smaller than the minimum size set in Detection Settings, then the animal is considered to be in the shelter.

The detection for exiting the hidden zone differs depending on whether you use the entry zone as a leaving zone:

• Without using the entry zone as a leaving zone, the subject is detected as having left the hidden zone as soon as the minimum subject size is detected anywhere within the arena. Depending on the minimum size set, only poking out the nose could count as "exiting".
• When using the entry zone as a leaving zone, the subject is detected outside the hidden zone, but will only be recognized as "out of the hidden zone" as soon as it crosses the border of the entry zone into the rest of the arena.

Define a Hidden Zone

1. At the bottom of the Arenas and Zones section, click the Add Hidden Zone Group button.
2. Create a zone covering the area you want to define as a hidden zone. If the Auto-label zones option is switched on, the zone is automatically named Hidden Zone 1. Right-click the name to rename it. If the auto-label option is switched off, click the Add Zone Label button on the toolbar, click the zone, and rename the zone.

Note: If a hidden zone is included in a larger, overlapping zone, the time spent in the hidden zone is not included in the results for the larger zone. See the note under the topic In Zone.