Knowledge Base

3 - Program Trial Control

3 Program Trial Control

If you just want record data for a specific time, you can do so by setting the maximum trial duration (page 21). If you want to start and stop data recording in relation to a few simple conditions (for example, start recording when the animal is detected in the water maze, and stop when the animal reaches the platform), define the Start/Stop trial rule (page 47). In other cases, see below.

procedure

1. Before defining Trial Control in the program, it is helpful to draw your experimental procedure as a flow diagram, where each block represents an action or a condition which, when met, triggers other actions or conditions. The logical order in the example below reads from left to right.
2. From the Setup menu, select Trial Control Settings, select New, enter a name of the new Trial Control Settings or accept the suggested one, and click OK. The default Start/Stop trial rule appears on the screen.
3. Build the Trial Control sequence outlined in step 1, using the components available. To define a Condition or an Action, click one of the buttons under Conditions or Actions. Insert the box in the appropriate place in the sequence. For conditions See page 26 and page 67 For actions on hardware devices See page 117 For actions on Trial Control variables See page 28 To define a set of actions and conditions to be repeated (Sub-rule), under Structures click the button next to Sub-rule (see page 55). Figure 9 An example of flow diagram representing the control of an operant conditioning test. The sequence is assumed to be repeated a number of times. 3 - Program Trial Control To define the command that calls a sub-rule, under Structures, click the button next to Reference. Insert the box in the appropriate place in the sequence (see page 57).
4. Test the Trial Control sequence (see page 42).
5. To apply Trial Control to your trials, before starting data acquisition make sure that the Trial Control Settings are highlighted in blue in the Experiment Explorer (see page 45).

Notes

When you create a new Trial Control element (action, condition, sub-rule or reference) and another of the same type has already been defined in this or other Trial Control Settings, a message appears asking you whether you want to create a new element or make a copy of the existing control. For more information, see page 36. A Trial Control variable is a variable that you can define to control your trials. For example, a counter variable that is incremented every time a specific event occurs. You can then define conditions and actions based on this variable. For more information, see page 28. If the experimental protocol is very complex, like in the case of a multiple-day recording session, it is handy to split the procedure in main blocks; then, for each block specify the basic actions and conditions, and whether the logical sequence should be repeated. This helps you identifying the main building blocks of your Trial Control logic, which will translate into Sub-rules. If you have inserted Condition boxes based on Activity in your Trial Control rule and then deselect Activity analysis in the Experiment settings (see Activity analysis in the EthoVision XT Help), the Condition boxes based on Activity are removed from your sequence and the connecting arrows are removed. This makes the rule invalid. Redesign your Trial Control rule and connect the arrows between the boxes. example A trial is to be run for a few days. On day 5 after the start, during the dark phase, an operant conditioning session must be repeated 10 times. On day 6, the same sequence must be carried out just once. If you choose to record video with EthoVision XT by selecting the option Save video only, track later in the Acquisition screen, Trial Control is applied when you do tracking, not when you record video. To start and stop video recording, do so manually. 3 - Program Trial Control Procedures that must be repeated or represent a specific task must be defined as Sub-rules (see page 55). Sub-rules can be called at specific times or under specific conditions. In the main Start-Stop diagram, draw a block that calls each sub-rule. See also the Main cases on page 38 for examples of logical blocks combined for a specific function. Figure 10 An example of a block diagram representing a multi-day conditioning schedule.

Figure 11 An example of a block diagram with

the main Start-Stop procedure (top) and two subroutines (sub-rules). 3 - Program Trial Control

conditions

A Condition is a statement that EthoVision checks during the trial. When the Condition is met (True), the program evaluates the next Trial Control element (another condition, an action or a reference to a sub-rule).

example Conditions are indicated in italics:

When the rat reaches the platform, stop tracking. When the mouse is around the novel object, switch on the light. When the animal presses the lever, drop a pellet.

To define a condition

1. In the Components pane, under Conditions, locate the type of condition you want to define.
2. Double-click the condition name or click the button next to it.
3. If the Add a condition window appears, it means that there is at least one condition of the same type in your experiment. You are asked to choose between creating a new condition, or re-use an existing one (see page 36). Choose the option you require and click OK. If this window does not appear, skip this step.
4. Next to Condition name, type in the name you want to give to the condition, or accept the default name.
5. Specify the condition properties (for details see page 67).
6. Enter a Comment (optional), then click OK.
7. Insert the condition box in the sequence. If the condition is complex (for example, Stop the trial either if the rat has reached the platform or it has been swimming for 60 seconds), then you must define separate conditions and combine them (see page 34). important If you have inserted Condition boxes based on Activity in your Trial Control rule and then deselect Activity analysis in the Experiment settings (see the EthoVision XT Help), the Condition boxes based on Activity are removed from your sequence and the connecting arrows are removed. This makes the rule invalid. Redesign your Trial Control rule and connect the arrows between the boxes. See also Main cases on page 38, and a detailed overview on page 67. 3 - Program Trial Control

actions

An Action is a command that EthoVision carries out during acquisition and that influences the trial.

example Actions are indicated in italics:

When the animal is detected in the arena, start tracking. This is an example of system actions (start tracking and stop tracking). When the animal enters the maze's left arm, do C= C+1. This is an example of actions on a Trial Control variable. See page 28. When the animal is found on the shelter, drop a pellet. This is an example of actions on hardware devices. See page 117. When the animal leaves the shelter, play a sound or present a visual stimulus. Or, when you start tracking, also start ultrasound recording with UltraVox XT. Those are examples of actions based on an external command. See page 31.

To define an action

1. In the Components pane, under Actions, locate the type of action you want to define: Trial Control variable for an action on a Trial Control variable. The device type name for actions on a Hardware device. External command to start an external program or run a batch file.
2. Double-click the action name or click the button next to it.
3. If the Add an action window appears, it means that there is at least one action of the same type in your experiment. You are asked to choose between creating a new action, or re-use an existing one (see page 36). Choose the option you require and click OK. If this window does not appear, skip this step.
4. Next to Action name, type in the name you want to give to the action, or accept the default name.
5. Specify the action properties: See page 28 for actions on Trial Control variables. See page 31 for actions on External commands. See page 117 for actions on Hardware devices.
6. Enter a Comment (optional), then click OK.
7. Insert the action box in the sequence. You cannot create additional actions of type Start track and Stop track, nor can you delete the existing ones. For an overview of frequent actions, see also page 38. 3 - Program Trial Control

trial control variables

You can define variables to be temporarily stored during a trial, that you can use to influence the control of the experiment. example 1 Variable as a marker. The variable Phase has been defined to specify the various phases of a trial (Phase = 1 means Conditioning; 2 Testing, etc.). The researcher can then program EthoVision to follow specific Trial Control sequences according to the current value of Phase. example 2 Variable as a counter. A researcher has defined the variable SR (successful response) to count the number of times the subject responds correctly to a stimulus. To increment the value of SR after a correct response, specify the formula SR= SR+1.

To define a Trial Control variable

1. In the Components pane, click the button next to Trial Control variable under Conditions or Actions. Next, click the TC Variables button.
2. The Trial Control Variables window lists the variables currently in the experiment (also those defined in other Trial Control Settings). To add a new variable, click Add variable.
3. A new row is appended to the table. Under Name, type in the name you want to give to the variable. Under Initial Value, enter the value of this variable at the start of the trial (default: 0).
4. Click OK. In the TC-variable action/condition window, define the action or condition you require. Click Cancel if you do not want to create a condition or action based on this variable at this point. To delete a variable, click the variable name in the Trial Control Variables window and click the Delete variable button. To rename a variable, click the variable name in the Trial Control Variables window and edit this name. The variable name cannot contain blank spaces. The default name of a new trial control variable is VarN, where N is a progressive number.

Actions on a Trial Control variable

To assign a new value to a variable in Trial Control, define a Variable action in your Trial Control rule. 1. In the Components pane, under Actions, click the button next to Trial Control variable. 2. If the Add an action window appears, it means that there is at least one action of the same type in your experiment. You are asked to choose between creating a new action, or re-use an existing one (see page 36). If this window does not appear, skip this step. 3 - Program Trial Control 3. Next to Action Name, enter the name of the action (for example, Increment Counter) or accept the default name. 4. Under Action to perform, select the variable from the list. You can also create the variable by clicking the TC Variables button if you have not yet done so. 5. Next to the "=" symbol, do one of the following: To assign the same value of another variable (for example A = B), select the other variable (B) from the second list. To enter a formula, click the double-arrow button. Select the operator from the list and specify the formula in the second and third lists. For example, A= A + 1.

To assign a random value, select Random from the second list, and enter the

Minimum and Maximum limits (only integer numbers 1 up to 999) in which the

random value must lay. When you select Random, the Permutation option also

appears. See below for details. 6. Enter a Comment (optional), then click OK. 7. Insert the resulting Action box in the Trial Control rule.

Random values and the Permutation option

When programming Variable ratio schedules, it is a good idea to use the Random option. Define a random variable R that specifies the number of rewards to be provided. Insert the resulting box in a sub-rule (see page 55). Every time the sub-rule is repeated, the variable R gets a new value. Make sure that the food dispenser is activated as many times as specified by R during that repeat. You can do this by calling a second subrule that activates the food dispenser (Action "drop pellet" followed by a time condition that waits for a short time interval like a few seconds). This second subrule is repeated as many times as specified by the value of R. You cannot combine Random with a formula (for example, to compute A= Random+1). The equivalent solution is the following: define first an action B= Random, and then one more action A= B+1. Place the two boxes in sequence. Select the Permutation option to generate a value in such a way that all n values within the specified range occur once before a value is generated again. For example, if you specify 1 as Minimum and 5 as Maximum (n = 5), the value 1 will be generated only when all five values in the range are generated in previous repeats of the action. In the following example, the Action is inserted in a subrule that is repeated a number of times at regular intervals. In the first five repeats, the numbers are generated in the following sequence: 5, 4, 2, 3, 1 (see the next image). A new value 5 can only occur at the 6th repeat (indicated with the arrow) or later, after all the numbers within the range 1-5 have been generated. 3 - Program Trial Control Use the Permutation option to create sequences of unique numbers, for example to define which door of a maze must be opened in a pseudo-random sequence.

Notes

If your setup includes multiple arenas, each arena receives an instance of the variable. Thus, a variable can have different values in different arenas. You can define several instances of variable-based actions and conditions in the same Trial Control profile. Such instances may well become active at the same time. Make sure that they do not interfere with each other. For example, two actions on the same variable are carried out in two different sub-rules (see page 55): If the actions A=1 and A=2 are evaluated at the same sample time, the value of the variable A after the actions are executed depends on the order of the Reference boxes those sub-rules refer to. If the reference to Sub-rule 1 comes first, A=1 is executed first. If references are placed in parallel, the order is undefined. In the Visualization, you can check which action is executed first (see page 42). 3 - Program Trial Control To analyze the values of a Trial Control variable, or visualize its values plotted against time, also for testing purposes, in the Analysis profile choose Trial Control variable.

external commands

Actions based on an External command

1. In the Components pane, under Actions, click the button next to External command.
2. Next to Action Name, enter a name for the (for example Play sound) or accept the default name. Click the Information button to get additional information about defining an External command.
3. Under Actions to perform, select which file you want to run by clicking the ellipsis button.
4. Next, select one of the file types from the list: Executables (.exe). Batch Files (.bat, .cmd). All Files (.*).
5. Locate the file and click Open.
6. Optionally, enter a Command line option.
7. To test the command, click the Test button.

Example 1 - Trigger Media Recorder to record video

You carry out live tracking during a 24-hour period and you want to record video with Media Recorder, but only when the animal is not in the shelter (defined as a Hidden Zone, where it spends most of its time). note For this configuration you need an analog camera. You must split the video signal from the cameras (using a BNC T-splitter connector) and send it to two BNC connectors of the Picolo Alert encoder board: one for tracking in EthoVision XT and the other for Media Recorder. In order for the board to receive correctly the two signals, you need to adjust the dip switches on the encoder board: usually On for the first input and Off for the second input. 1. First, create an External command box to start Media Recorder. Choose Executables (*.exe) and select MRCmd.exe as the application to run. As a Command line option, enter /E to specify that the external command launches Media Recorder. 3 - Program Trial Control 2. Next, insert a Condition Out of shelter and combine this with a Time condition to make sure that Media Recorder is launched before recording starts (see Figure 12 for an example). 3. At the right of the Operator box insert a second External command box, this time to start video recording: select MRCmd.exe as the executable to run and enter /R as a Command line option to start recording (see the last box in the figure below). 4. Similarly, you can have EthoVision XT stop recording (Command line option: /S) when the subject enters the shelter again (not shown here). note There may be a delay between the command Start Recording and the moment Media Recorder actually starts recording. Run a test recording to measure that delay.

Example 2 - Trigger UltraVox XT to record ultrasound

In this scenario, you plan to video-track mice with EthoVision XT and, at the same time, record their ultrasonic vocalizations with UltraVox XT. For ease of use you want to start and stop recording from one place - EthoVision XT. Define an External command action based on the batch file SUV.bat (see 1 in the figure below). This file is located in C:\ProgramData\Noldus\Common\Tools\UltraVox XT 3 Control. Note that you need to edit this batch file depending on your computer name or IP address. In the figure below, Condition 2 determines the duration of the recording. Action 3 stops recording in UltraVox XT. Figure 12 Example of the External command action to start a recording with Media Recorder when the animal leaves a shelter. The left Start MR action box starts up Media Recorder. The Start Recording action box on the right starts the recording when both the Out of Shelter and Time(1) conditions are true, that is, the center-point of the animal has left the shelter at least 5 seconds after Media Recorder was started. 3 - Program Trial Control Furthermore you must set UltraVox XT to automatic start/stop recording. For more information, see Control UltraVox XT from other software in the UltraVox XT 3 Help.

Example 3 - Run a batch file

You want to play a sound during your trials. You can do this by running a batch file (*.bat or *.cmd) using an External command action in EthoVision. In the figure below, an action has been defined with the batch file Play sound.bat. The batch file Play sound.bat starts Windows Media Player and plays the sound file

Stimulus_sound.wav. Its content is:

start "%ProgramFiles%\Windows Media Player\wmplayer.exe" D:\temp\Stimulus_sound.wav Arena and Trial names. When using a batch file, you can use the command line options

%an% and %tn% to send information about the Arena and the Trial name in command

lines from the Trial Control rule. For example, during a batch acquisition of trials you could send the trial name information to an external program, which starts a procedure when trial name (%tn%) becomes Trial 10. In the following example, a batch file has been created to display the current Trial name and Arena name in the DOS window (one for each arena, in the case of multiple arenas). Echo %1 and Echo %2 listen to the values of %an% and %tn% in the order specified in the command line options. The DOS window is set to close 5 seconds later: echo %1 echo %2 PING 1.1.1.1 -n 1 -w 5000 >NUL 3 - Program Trial Control In the External command Action window, specify the name and location of the batch file, and enter the command line options %an% %tn% (lower case only; parameters must be separated by space). important Contrary to what worked in EthoVision XT 12 and older, %an% %tn% are not written with quotes. For example %tn% becomes Trial 1, not "Trial 1".

operators

Aim

The Operators help you combine actions, conditions and sub-rules in various ways.

examples

When at least one of the two conditions A and B is met, then do … . This is an example of conditions combined by an operator of the "Any" type (OR logic). When two conditions are met at the same time, then do … . This is an example of conditions combined by an operator of the "All" type (AND logic). When at least/at most/exactly 4 of 8 conditions are met, then do … This is an example of conditions combined by an operator of the "N of All " type.

Procedure

1. Define the conditions/actions/rules that you want to combine. Place them in your Trial Control sequence as parallel branches as in the figure below. 3 - Program Trial Control
2. In the Components pane, under Structures, double-click Operator or click the button next to it.
3. If the Add an operator window appears, it means that there is at least one operator of the same type in your experiment. You are asked to choose between creating a new operator, or re-use an existing one. If this window does not appear, skip this step. Create a new operator. A new operator is created. Re-use an existing operator. Select the name of the operator already present in your experiment. See page 36 for more information. Click OK. The Operator window appears.
4. Under Name, enter the Operator name or accept the default name Operator (n), where n is a progressive number.
5. Under Operator triggers when, select the option that applies: Any (at least one) of the inputs is 'true'. All inputs are simultaneously 'true'. N of All inputs are simultaneously 'true'. Where 'true' means a condition met, an action carried out, or a sub-rule finished (depending on the elements you want to combine). If you choose the third option, specify how many inputs must be 'true': = (exactly equal to), not= (not equal to), >= (at least), <= (a maximum of), etc. Specify the number in the box.
6. Enter a Comment (optional) to describe this operator, and click OK.
7. A new Operator box appears in the Trial Control. Place the box right of the elements defined in step 1, and connect each element to the operator box. 3 - Program Trial Control
8. Connect the operator to the next element in Trial Control sequence.

Notes

Names of operators must be unique in your experiment. You cannot define two operators with the same Operator name, even if these are defined in two different Trial Control Settings. An Operator can also have just one input box. In that case the operator is of no use, because control passes immediately to the next box as soon as the input condition becomes true or the input action is carried out. EthoVision informs you about this. Operators can also combine sequences of elements. For example:

Sequence 1 - When the animal presses a lever (Condition), then drop a food item

(Action). Sequence 2 - Time= 5 minutes (Condition; this equals to waiting 5 minutes). If you want the program to take an action when either sequence has been completed, combine the two sequences with an "Any" operator.

re-use trial control elements

The elements of Trial Control (conditions, actions, operators, sub-rules and sub-rule references) that you have defined in other Trial Control Settings can be duplicated and re- used in the current Trial Control Settings to reduce your time spent editing. To re-use all the elements defined in your current Trial Control Settings profile, make a copy of it: right-click the profile in the Experiment Explorer and select Duplicate.

To re-use a Trial Control element

1. Click the button next to the category of element that you want to re-use.
2. The Add window appears. Select Reuse an existing condition/ action/ sub-rule/ reference. This window does not appear when the experiment contains only one Trial Control Settings profile, or the experiment contains more Trial Control Settings profiles but none of them contains an element of the same type as that you have chosen.
3. Select the name of the existing element from the list next to the option. The second list shows the Trial Control Settings profile that contains that element. If the element is present in multiple Trial Control Settings, choose the appropriate one from the list.
4. Click OK. 3 - Program Trial Control
5. A window appears for the type of element chosen. The Name and settings specified here are the same as in the element chosen in step 3. To create an identical copy of the element, click OK and go to step 7. In all other cases, edit the settings and click OK, then go to step 6.
6. If you have changed any property of the new element (including name and comment), a window appears showing two options: Apply the new settings only in the current Trial Control profile. Apply the new settings in all writable Trial Control profiles. The program asks you whether you want to apply the properties only to the new copy, or to extend those changes to the original elements in all Trial Control Settings that are writable (that means, not locked after acquisition). Choose the option you require and click OK.
7. Insert the resulting box in the Trial Control sequence.

Notes

If you choose the option Apply the new settings in all writable trial control profiles, changes are not made in those profiles made read-only after data acquisition. The program does not ask you whether you want to re-use the Trial Control element if no element of the same type has been defined in the other Trial Control Settings. You cannot re-use a Trial Control element from the same Trial Control Settings. This is because the Trial Control elements must be unique in order for correct analysis to be done. 3 - Program Trial Control

frequently-occurring cases

Have an action taken when a condition is met

example A food pellet is dropped (Action) when the mouse is detected in the zone that marks the top of the shelter (Condition). The condition must precede the action. In the example above, the condition is based on a zone. The action is performed on the Pellet dispenser.

Have two actions taken at the same time

example In a radial maze experiment, make sure that the device Door 1 opens at the same time when Door 2 closes. Define two action boxes, one for each door device. Next, do one of the following: Place the two action boxes in parallel, and combine them with an All operator (see page 34). Place the two action boxes one after the other. The time between the two actions is negligible.

Specify a time interval between actions/conditions

example Wait one minute between the action Cue Light On and the action Drop one pellet. Insert a Time condition box between the two existing boxes (see also the next case).

Make multiple instances of an action

example In a conditioning experiment, drop two food pellets in sequence. The two actions are placed in a linear sequence. If the action is performed on a hardware device, insert a Time condition between the two action boxes, for example wait 10 s before proceeding to the second action. If you do not do this, EthoVision XT interprets the twin actions as one. In the example above, it would deliver one food pellet only. 3 - Program Trial Control If the pellet dispenser is almost empty, it may take up to 30 seconds to deliver a pellet. make sure that the time specified in the Time condition exceeds the time that it takes the action to be carried out. Another possible solution is to place a condition based on hardware between the two actions, that checks that the Number of pellet drops is >=1 before taking the next Drop pellet action.

Have a sequence of conditions and actions repeated

example Make sure that the sequence Mouse on Shelter --> Drop one pellet on page 38 is repeated every time the animal is found on the shelter. Define a Sub-rule (see page 55) and insert the sequence of conditions and actions in it. Next, create a Reference to that sub-rule, and specify when and how many times the sequence must be repeated (see page 57).

Give a reward after multiple instances of the subject's action

example In a Fixed Ratio schedule, it is required that the animal has to press the lever three times (Action) before getting a reward. Define a Trial Control variable C that counts the number of lever presses. The action C=C+1 is triggered every time the condition Lever pressed is met.

Define a Sub-rule that includes the sequence Condition Lever pressed

Action C=C+1. Define a Reference for that sub-rule, and specify that the sub-rule must be repeated until C reaches the value required 3. Place the Action box for Drop a pellet immediately after the sub-rule's Reference box. For more information: On Trial Control variables. See page 28. On sub-rules and references to sub-rules. See page 55 and page 57. 3 - Program Trial Control

Have an action taken when a condition is met within a specific time

example Have EthoVision XT drop a food pellet when the animal visits zone A within 1 minute from the release of a light stimulus. Define the main condition (in the example above, animal in zone A. Specify that the Current value of In zone must be true. Define the action that must be taken (Drop a pellet). Define the accompanying Time condition (Wait one minute). Place the main condition followed by the action. Place those two boxes in parallel with the Time condition, using an operator of "Any" type. With such a sequence, the food pellet is dropped as soon as the animal is found in zone A. If the animal does not go to zone A, one minute after the light was switched on the Time condition is met, and the operator becomes active. Therefore, control passes to the box following the operator, and the In zone condition is no longer evaluated. With this solution, the action Drop a pellet is not taken when the animal enters zone A more than one minute after the light has been switched on. important If you combine the two conditions above with an operator of All type, the program may wait indefinitely until both conditions are met.

Have different actions taken according to different conditions

example A T-maze is provided with two doors, one in the middle of arm A and one in the middle of arm B. It is required that door A is opened when the animal enters arm A, and door B when the animal enters arm B. Define two conditions, one for arm A and one for arm B. For both conditions, specify that the Current value of In zone must be true. 3 - Program Trial Control Define two actions, one for opening door A and one for opening door B. Connect each condition to the corresponding action. Next, connect the resulting sequences through an operator of the "Any" type.

Define phases in a trial

example It is required that tracking occurs in different phases of a trial, for example, Baseline, Conditioning, and Testing. In each phase, different trial control rules must be applied. For each phase, define a Sub-rule (see page 55) with its actions and conditions. Specify when the sub-rule must start. For each sub-rule, define a Sub-rule reference and insert it in the Start/Stop rule. Make sure that the references are in the order specified in your experimental protocol. 3 - Program Trial Control

test the trial control sequence

It is not easy to make a complex Trial Control sequence work right the first time. To check that Trial Control works as expected, follow this procedure: 1. Make sure that the Trial Control Settings that you want to test are highlighted in blue in the Experiment Explorer. Otherwise, click the Trial Control Settings you want to test. 2. Open the Acquisition menu (Choose Acquisition > Open Acquisition. 3. Click Show/Hide and choose Show Dependent Variable. Choose Trial Control Event for simple events like Action Drop a pellet becomes active, or Condition Subject in zone A becomes true. Choose Trial Control State to select the time between events occurred during the trial. for example From Action Light On To Condition In Trigger zone True. This will show the time interval from when the light switches on to when the animal enters the Trigger zone. 4. Start a trial. Watch the Trial Control Events or States in the Analysis Results and Scoring Pane at the bottom of your screen. 5. Create an Analysis profile and use the Trial Control event /state/variable and other dependent variables to specify the events you want to visualize. See page 168 for details. 6. To visualize the trial, choose Analysis > Results > Plot Integrated Data. Trial Control data are visualized as vertical segments (for events, with no duration) or horizontal bars (for states, with a duration) along the time line. Examine the data and check that EthoVision XT has responded as expected. Figure 13 Visualizing Trial Control data. Top: Dependent variable In zone "On Shelter". Middle: Trial Control event that marks the time when the Zone transition condition is met. Bottom: Trial Control event that marks the time when a food pellet is dropped. 3 - Program Trial Control 7. You can also check when exactly a condition becomes active or true, or when a command is given by looking at the Trial Control Events pane at the bottom-right corner of your screen. Select an Arena name from the list to visualize the sequence of Trial Control for that arena. Play the track. The red hairline moves along the sequence and shows at what point Trial Control is. Play the track frame-by-frame to see when exactly a condition becomes true, or a command becomes active. In the following example, a Trial Control sequence is defined: Condition: In trigger zone Action: Drop pellet Condition: In feeder zone. Play the track until the cursor gets between Condition: In trigger zone - becomes false and Condition: In trigger zone - becomes true. This is the time when the condition is activated and the program waits until the animal enters the trigger zone. At 15.48 s the condition becomes true. The program executes the instructions that follow (Action: Drop pellet) and positions at the next condition (In feeder zone) until that becomes true too. 8. Make the necessary corrections to the Trial Control rules and start again from step 2. Figure 14 The Trial Control Events pane. 3 - Program Trial Control

Notes

For a clear overview of the Trial Control events occurring during a trial, for each Trial Control box (except the Rule End box) define three dependent variables (step 3 above):

Trial Control event - under Element, choose which box to test, and under Event,

choose becomes active. This marks the time when an action is taken, a condition is evaluated, or a sub-rule is activated.

Trial Control event - under Element, choose which box to test, and under Event,

choose becomes inactive. This marks the time immediately after an action is taken (this is usually not distinguishable from the time the action is taken), a condition is met, or a sub-rule is completed.

Trial Control state - Select From when the box becomes active To when the box

becomes inactive. This will display a colored bar that marks the time that the box is activated up to when it is deactivated. Define also one or more a In zone dependent variable to monitor the position of the animal. Once you have carried out a trial, the Trial Control Settings used for that trial are locked. To edit them, either delete the trial acquired in step 2 or make a copy of the Trial Control Settings (right-click the Trial Control Settings in the Experiment Explorer and select Duplicate). To check at what time an action is taken or a condition is met, you can also export the Trial Control events specified in step 2 and the Hardware log data (see page 185). You can also test your Trial Control Settings by providing visual/audible feedback during the trial. Define an action box that calls up some feedback once the program has reached a specific point in the Trial Control sequence. Insert this box immediately right to the condition/action/rule reference box that you want to test. To test hardware devices, see page 115. 3 - Program Trial Control

apply trial control to your trials

To apply Trial Control to your trials, make sure that the Trial Control Settings profile containing that logic is highlighted in blue in the Experiment Explorer. Test your setup thoroughly before carrying out the actual trials (see page 42).

For setups with multiple arenas

Trial Control is applied to each arena independently.

Locked Trial Control Settings

When a Trial Control Settings profile is used for acquiring at least one trial, it becomes locked. Locked settings are indicated by a lock symbol in the Experiment Explorer, and cannot be edited. To edit a locked Trial Control Settings profile, make a copy of it and edit this copy.

Track from pre-recorded video files

When you track from video files, Trial Control checks conditions using video time instead of the real time. Conditions based on time. If you select the Detection Determines Speed option, Trial Control is carried out at the speed set by EthoVision in order not to skip video images). This results in the video playing faster or slower than normal (1x), depending on the processor load necessary to detect subjects. For example, if detection requires little processor work, the program tracks the subject faster than normal. A time condition (for example, 60 s) is therefore met earlier than at real time.

Using Clock time. If you define a condition based on clock time, or schedule a

sub-rule with Clock time, this is translated into the video start time, that is, the date and time the video file used for tracking was created. example 1 You set a Time condition to start tracking After clock time 11:30. The video file was created on March 6, 2008 at 11:00. once you start the trial, the condition is met half an hour later in the video. If you had set to start tracking After clock time 10:30, tracking would start immediately after starting the trial. example 2 You set a sub-rule to start at 10:00 (1st day). The video file was created on March 6, 2008 at 11:00. Once you start the trial, the sub-rule never starts, because the planned start occurs before the initial time of the video. To make a sub-rule start when tracking from that video, set the start time between 11:00 and the video end time. 3 - Program Trial Control

Record video, then track the subject

You can choose to record video first and then acquire data from the resulting video file. You do this by selecting Save video only, track later in the Acquisition screen. When recording video, Trial Control is turned off. You get an appropriate message when selecting the option Save video only, track later. When you track from the video recorded in the previous stage, Trial Control for Start- Stop is activated, but you cannot control hardware devices.

Re-do a trial

For video files recorded with EthoVision, you can re-do the corresponding trial (see 'Redo trials' in the EthoVision XT Help). However, if you re-do a trial the Trial Control log files recorded with the previous instance of the trial are deleted.

Stop a trial

When you stop the trial, all rules active in the Trial Control Settings are ended immediately, and hardware devices are reset.

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