Knowledge Base

Arenas (Continued)

Apply Different Protocols to Different Arenas

Define the Protocols

Make a sketch of the events in each arena. Draw a time line for each arena. On the time line, write down the events that should occur, and their duration. This will help creating the Trial Control protocols.

Trial Control Settings

There may be parts of the protocol shared between arenas. In the example of Figure 59, the first 30 seconds after the start of the trial are the same for the two arenas. Therefore, one condition box after the Start track box will suffice.

The sequence of instructions for the two treatments must originate from the same point (so they will start at the same time) and proceed in parallel.

Note that the two branches do not have to end back into the main start-stop sequence. However, you must make sure that the trial does not stop before the two branches have been processed. In this example, we have set the trial to stop after 2 minutes. Therefore, a Time box has been added to the Start-stop sequence that waits 90 s to complete the trial (30 s of the first box + 90s = 120 s).

Sequence for Arena 1 — According to the protocol, for Arena 1 the light must be switched on immediately after the 30 s period, then 2 s later it must be switched off. This can be programmed with two hardware actions (ON and OFF) and a Time condition in between. The actions must specify the device Light Arena 1.

Sequence for Arena 2 — According to the protocol, for Arena 2 the light must be switched on at a time randomly chosen between 0 and 90 s. This can be programmed with a time condition that determines the random time, followed by a sequence similar to that for Arena 1. The actions must specify the device Light Arena 2.

The Random time condition defines a time between 0 and 88 seconds, to make sure that the 2-seconds light flash is always given in its entire duration within 90 seconds.

Repeat a Sequence Within the Trial

In most cases, a sequence of actions is repeated a number of times, or until a condition is met. If you want the two sequences described above to be repeated, you must use the Sub-rule function in Trial Control.

The Sub-rule settings ensure that the sub-rule is repeated 10 times, and the time between the start of 2 successive repeats is 2 minutes. For more information on how to use Sub-rules, see Sub-rules.

Advanced Case: Six Arenas

In this use case, we plan to record data in six arenas, with one animal per arena. This use case is considered advanced for several reasons:

• Each treatment (odor stimulus and a subsequent foot shock) is duplicated in two arenas. This example shows that even when two of a number of arenas share the same protocol, each arena must have its own trial control procedure with unique Device names defined.
• Together with two treatments that require different protocols, a third group (control) is added that requires no foot shock. Control animals are recorded simultaneously with the other animals.
• All animals share part of the protocol. They all receive an odor stimulus by means of an olfactometer. Therefore, part of the Trial Control procedure must work for all arenas.
• All hardware devices are assumed to be controlled through TTL commands.

Experiment Settings

1. Connect all hardware devices to the EthoVision XT computer, via the appropriate port in the Noldus USB-IO box.
2. In the Experiment Settings, select the Number of Arenas.
3. Under Trial Control Hardware click Settings.
4. In the window that opens, select Noldus USB-IO box.
5. In the Device Configuration window, assign a hardware device to a port of the USB IO box. Here Device ID represents a name for each physical device. For example, Shocker 1 will be installed in Arena 1, Shocker 2 in Arena 2, etc.

Since the olfactometers work the same way in all arenas, they can be connected to the same port of the USB IO box. Therefore, you need 4 ports for the shock generators (Arenas 1 to 4) and one port for the olfactometer.

Arena Settings

1. In the Arena Settings, define and calibrate the arenas as usual. Next, click the Arena - Hardware Mapping button in the Arena Settings window.
2. In the Arena - Hardware Mapping window, click Add Device two or more times to create multiple rows, one row for each physical device that has to work independently. In this case, 5 rows.
3. For each arena, assign a device in a different row. Make sure that the other cells of the row show <No device allocated>.

Note that:

• Although Arena 1 and 2 and Arena 3 and 4 share the same treatment, they must be linked to different Device names. This is to avoid that any command given to, for example, the shocker in Arena 3 does not go to Arena 4.
• In the last row of the Arena - Hardware Mapping window, the olfactometer is selected for all arenas, using the Device name Olfactometer. This name will be used in Trial Control.

Source: EthoVision XT 18 - THC - Trial and Hardware Control, Noldus Information Technology