Knowledge Base

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 and analysis of Trial Control data. 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.

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 18 > Other Documentation. There you find:

• EthoVision XT 18 - Application Manual for information on common tests including conditioning tests that make use of sub-rules in the Trial Control Settings.
• PhenoTyper - EthoVision XT 18 - Reference Manual for information on PhenoTyper and how to connect it to EthoVision XT.
• PhenoTyper - EthoVision XT 18 - Service Manual for information about PhenoTyper and devices such as the Noldus Pellet dispenser, the Noldus Lickometer 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.
• 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.
• 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.

To Use Trial and Hardware Control

1. Open the Trial Control screen.
2. Define the conditions that, when met during your trial, trigger specific actions. Organize conditions and actions in sequences.
3. Before starting data acquisition, 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.

You define and link conditions with actions in a graphical form. 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.
• Sub-rules (available only in EthoVision XT with the Trial and Hardware Control Module): 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.

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 box:

• Condition Box: EthoVision XT waits until the condition is met. When this happens (condition becomes true), the program passes control to the next box in the sequence. The condition then becomes inactive.
• Action Box: EthoVision XT carries out the action and passes control to the next box, which becomes active. The Action box then becomes inactive.
• Sub-rule Begin Box: Control is passed to the box that follows. The Sub-rule Begin box becomes inactive.
• 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.

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