Knowledge Base

1 - Introduction to Trial Control

1 Introduction to Trial Control

this manual

This manual is meant for all users of EthoVision XT: For users of the Base version. You can find extensive information on the Trial Control conditions (see page 67) and analysis of Trial Control data (see page 168). This information is not present in the EthoVision XT Help. For users of the Base version plus the Trial and Hardware Control module. You find all the information you need in this guide. If you use EthoVision XT in combination with hardware devices, you can find the relevant information in Section 7 (page 104).

EthoVision XT Help

For extensive information on EthoVision XT or for troubleshooting, see the EthoVision XT Help. In EthoVision XT, choose Help > EthoVision XT Help or press F1.

Other documentation

From the Windows Start menu choose All Apps > Noldus > EthoVision XT 17 Other

documentation. There you find:

EthoVision XT 17 - Application Manual for information on common tests including

conditioning tests that make use of sub-rules in the Trial Control Settings. PhenoTyper - EthoVision XT 17 - Reference Manual for information on PhenoTyper and how to connect it to EthoVision XT. PhenoTyper - EthoVision XT 17 - Service Manual for information about PhenoTyper and devices such as the Noldus Pellet dispenser, the Noldus L5ickometer and PhenoWheel. DanioVision DVOC-0041 - Reference Manual if you use Trial Control with the DanioVision Observation Chamber.

why use trial and hardware control?

Trial Control allows you to automate your experiment. For example: You want to set a maximum duration for your trials. See page 41. 1 - Introduction to Trial Control

You want to automate the start and/or stop of data acquisition. For example:

Start recording when the rat is first detected in the open field. Stop recording when the rat has reached the platform in the Morris water maze. Start recording at exactly 12:30:00. Stop recording after the animal has been in the closed arms of the plus maze for 5 minutes. See page 47 and also page 23 for general information.

You want to automate conditioning schedules, or operate hardware devices. For

example: When the animal presses a lever, have the food dispenser drop a food pellet. When the animal leaves the shelter, use an External Command action to start a recording with Media Recorder. When the animal enters the shelter, turn on a light. Close the door of a radial maze when the animal has exited that arm. See page 23 for general information and page 55 for making sub-rules.

To use Trial and Hardware Control

1. Open the Trial Control screen (see page 16).
2. Define the conditions that, when met during your trial, trigger specific actions. Organize conditions and actions in sequences (see page 23).
3. Before starting data acquisition, you make sure that those Trial Control Settings are active. For information on how to manage Trial Control Settings, see also Settings and profiles, under File management in the EthoVision XT Help.

conditions and actions

A Condition is a statement that EthoVision evaluates. An Action is a command executed on a variable or a hardware device. You can therefore control your experiment by linking conditions with actions. example 1 In a Morris water maze test, stop tracking when the rat reaches the platform (provided that the platform has been defined as a zone). Stop tracking is the action and Rat on the platform is the condition. example 2 In a Fixed Ratio schedule, have EthoVision send a command to drop a pellet when the mouse has been detected in the Trigger zone. Drop one pellet is the action and Mouse in the Trigger zone is the condition. 1 - Introduction to Trial Control You define and link conditions with actions in a graphical form. Example 2 can be represented with the following: For more information on conditions, see page 26 and page 67 For more information on actions, see page 27. You can copy, move, connect and delete Trial Control elements such as actions and conditions. For how to do so, see the EthoVision XT Help.

trial control rules

A Trial Control rule is a set of conditions and actions organized in a logic sequence. It can be viewed as a set of instructions executed during a trial. There are two types of Trial Control rules: Start-Stop trial rule. For starting and stopping data acquisition. This rule cannot be repeated or deleted. For details, see page 47. Sub-rules (available only in EthoVision XT with the Trial and Hardware Control Module, see page 14). Subroutines of the Start-Stop trial rule, which are meant to carry out specific actions. Sub-rules can start at specific times and be repeated according to conditions specified in a Sub-rule reference. For details, see page 55.

Figure 1 A condition is followed by an action. The

condition checks that the animal is in the zone named "Trigger zone". The action "Drop a pellet" is taken when the condition is met. Figure 2 Schematic representation of a generic sub-rule. 1 - Introduction to Trial Control

how trial control instructions are executed

The instructions contained in the Trial Control Settings are carried out from the moment you start a trial, to the moment the trial is stopped. Only the instructions in the Trial Control Settings currently active (that is, highlighted in blue in the Experiment Explorer) are carried out. The program evaluates the Trial Control sequence at each sample time. The rate at which this happens depends on your chosen sample rate, not on the video frame rate. For the Start-Stop trial rule and each active sub-rule, the program remembers which Trial Control boxes were evaluated (active) in the previous sample. Depending on the type of this box: For a Condition box. EthoVision XT waits until the condition is met. When this happens (condition becomes true - see 3 in Figure 3), the program passes control to the next box in the sequence. The condition becomes then inactive (see 4 in the same figure). For an Action box. EthoVision XT carries out the action (see 4 in Figure 3), and passes control to the next box, which becomes active. Then, the Action box becomes inactive (see 5). For a Sub-rule Begin box. Control is passed to the box that follows. The Sub-rule Begin box becomes inactive. For a Sub-rule End box. This marks the end of a sub-rule. The sub-rule becomes inactive. Control is passed to the Reference box that had called that sub-rule. This Reference checks whether the sub-rule must be repeated. If this is not the case, control is passed to the box following the Reference box. For a Reference box. Control is passed to the Sub-rule Begin box. The Reference box makes the sub-rule active. The Reference box stays active until the last sub-rule repeat is completed. Next, the Reference box makes the sub-rule inactive and passes control to the box that follows. Next, the Reference box becomes inactive. The events marked in italics above are those you can define in the Analysis profile and analyze or visualize in a chart (see page 168). When a box becomes active, the previous one becomes inactive. 1 - Introduction to Trial Control Figure 3 Schematic representation of how Trial Control Instructions are executed. The scheme shows an example of a Start-Stop trial rule (see page 47). 1 - Tracking starts, either manually or because a previous condition has been met. 2 - Control passes to a Condition box (for example "Is mouse on top of Shelter?"), which becomes active. The condition is evaluated. 4 - Control passes to the next box. In this case, it is an Action. Actions are taken immediately (but see the note below on actions on hardware devices). For clarity, step 3 and 4 have been placed separately. In reality, when a condition becomes true it also becomes inactive at the same sample time, and control passes to the next box. Hatched outlines - Condition box becomes active. Dark outlines - Condition becomes true or Action is taken. Pale outlines - Box becomes inactive. 1 - Introduction to Trial Control When plotted against time (see page 168), events like those in Figure 3 look like as follows:

Evaluation of Trial Control boxes

Boxes combined in parallel using operators (see page 34) are evaluated at about the same time, in random order. This means that you cannot establish which condition is evaluated/which action is taken first. When your trial control is complex, for example when it includes sub-rules or conditions combined with operators, it is possible that two or more Trial Control boxes are evaluated at the same sample time. When a condition based on a dependent variable is evaluated (and therefore may or may not be met) also depends on the statistic used. See page 78 for details. If two or more boxes are evaluated at the same time, an action on a hardware device is taken only after all active boxes that must be evaluated have been evaluated. If the next box to be evaluated contains a condition that is fulfilled immediately, the program passes control to the next box. Therefore, within one sample time the program can pass control to two or more boxes to the right. Figure 4 Time plot of the events of Trial Control represented in Figure 3. The time that the animal is in the zone "Top of Shelter" is indicated by a horizontal bar. When tracking starts, the Action "Start track" becomes active (1st line) and immediately inactive (2nd line) as control passes to the next box. The condition "On top of Shelter?" becomes active (3rd line; see 2 in Figure 3) and immediately false (4th line) since the animal is not in that zone. When the animal enters the zone, the condition becomes true (5th line), and becomes immediately inactive (6th line) as control passes to the next box (see 4 in Figure 3). The action becomes active (7th line) and immediately inactive (8th line) as the command "drop a pellet" is sent to the pellet dispenser. 1 - Introduction to Trial Control When you stop the trial or the Maximum trial duration has been reached, all Trial Control boxes are deactivated. When the Rule End box of the Start/Stop trial rule is evaluated for an arena, data recording stops for that arena. From that moment, Trial Control is deactivated for that arena, even in those sub-rules that were ongoing in the meantime (see also the next page). A trial stops when trial control is deactivated in all arenas. Actions on hardware devices. A command is sent to a device after all boxes that must be evaluated have been evaluated. However, it may take some time for the outcome to be seen. For example, when a pellet dispenser is almost empty it may take a few seconds before a pellet is released. important When two or more actions on hardware devices follow each other, it is possible that they are evaluated at the same sample time. This happens because the computer is fast enough to analyze multiple Trial Control boxes in the sample interval. To make sure that actions are taken in the correct sequence and do not interfere with each other, add a Time condition (see page 142) between the action boxes, so after the first action is carried out EthoVision XT waits for a short time (for example, 0.1 s) before carrying out the next one. Sub-rules. A sub-rule is completed when the Rule End box has been evaluated, or when it is interrupted (see page 61 for more information). If two or more sub-rules are evaluated at the same time, it is not possible to establish which sub-rule is evaluated first at a specific sample.

Trial Control in multiple arenas

If your experimental setup includes two or more arenas, Trial Control is applied to each arena separately. This means that, if a condition is met in one arena, EthoVision XT takes the corresponding action in that arena, not the others. example See Figure 5. The setup includes four cages, each defined as an arena. A Trial Control In zone condition (see page 84) has been defined so that tracking starts when the animal is first detected in the arena. When you first put an animal in Arena 2, the condition is met in this arena and tracking starts for that arena. When you release the second animal in Arena 4, 2 seconds later, tracking in that arena starts 2 seconds later than in Arena 2. 1 - Introduction to Trial Control The advantage of Trial Control in multiple arenas is that you can put one animal at a time into the arenas, and EthoVision XT will start tracking in each arena at the appropriate moment. If your setup includes multiple arenas, you cannot define a condition/action specific to one arena. This means that the zones and hardware devices specified in the condition/action must be present in all arenas, and have the same name. If a zone or hardware device is not present in an arena, and a condition is based on that zone or device, Trial Control cannot progress for that arena. Therefore, tracking does not stop unless you set a maximum trial duration or tracking reaches the end of the video. Trial Control executes the instructions for each arena separately, however one cannot establish which arena is evaluated first at a specific sample time.

your ethovision license and trial control

Your EthoVision XT license determines which type of Trial Control you can set up. EthoVision XT Base license. You can define a rule to start and stop data recording (Start- Stop trial rule; see page 47), not sub-rules. You can also use an External command action. You cannot control hardware devices. EthoVision XT Base + Trial and Hardware Control Module. You can define a Start/Stop trial rule (see page 47), and in addition sub-rules (see page 55) that serve as subroutines of the Start-Stop trial rule. Moreover, you can control hardware devices. To acquire data in an experiment created with the Trial and Hardware Control Module, you must have a license that includes this module.

Figure 5 Trial Control in multiple arenas. The

time values displayed on the monitor are the time elapsed since the start of tracking in a particular arena. Tracking started earlier in Arena 2 than in Arena 4 (see text), therefore at any time the Elapsed time (duration of tracking) is longer in Arena 2 than in Arena 4. 1 - Introduction to Trial Control For more information on your EthoVision XT license, see the EthoVision XT Help.

analysis of trial control data

The Trial Control function also allows you to easily analyze events that occurred during the trial. For example, in a conditioning experiment: Number of rewards. Calculate the number of pellets dropped during a trial. Latency between action and reward. Calculate the time interval between the time the animal pressed the lever and the time the animal approached the pellet dispenser. Number of failures. Calculate the number of times the animal approached the lever during the period between 'dropping the pellet' and 'animal approaching the pellet dispenser'. That is, how many times the animal pressed the lever when a reward was already available. You analyze Trial Control data the same way as for the behavioral variables. In the Experiment Explorer, open an Analysis profile, and specify the data you want to analyze (Trial Control event for point events, Trial Control state for time intervals between two events). For the detailed procedure, see page 168.

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Source: EthoVision XT 17 - Trial and Hardware Control Reference Manual