Knowledge Base

Conditions

A condition can be based on:

• On Time (see below) or a Time interval.
• On a Trial Control variable.
• On a Dependent variable like Distance moved, In zone, Mobility, etc.
• A combination of dependent variables, like "is the subject moving above a certain speed and is it in a certain zone?"
• On a Manually-scored behavior.
• On a Hardware device.

Conditions Based on Time

With a Time condition, some time must elapse before the next Trial Control box is evaluated.

1. In the Components pane, under Conditions, double-click Time or click the button next to it. The Time condition window opens.
2. Under Name, enter a Condition Name.
3. Select one of the following options:
   • After. To have an action been taken some time after the condition becomes active.
     Example: Start tracking after two seconds.
   • After a random time. To have an action been taken with a delay chosen randomly between two time limits. Enter the lower and higher limits and choose the time unit (seconds, minutes, or hours). The random value is counted from the moment the condition becomes active. Choose this option when programming rewards in a variable interval schedule.
     Example: At the end of a random time between 10 and 30 seconds (condition), drop a food item (action).
   • At clock time. To have an action been taken at an absolute time (hh:mm:ss).
     Example: At 12:00 AM (condition), start tracking (action).
     Note: If you want to start tracking at 12:00 AM of the next day, and you click Start Trial in the afternoon of the current day, EthoVision XT starts tracking immediately because it sees that the condition 12:00 AM has been met already. For how to solve this, see the topic Start and stop the trial at specific clock times in the EthoVision XT Help.
   • Infinite time (condition never met). To wait indefinitely (see the notes below).
4. Insert a Comment (optional) and click OK.
5. The Condition box appears in the upper-left corner of the Trial Control screen. Insert it in the appropriate position in the Trial Control sequence. For information on how to insert a Trial Control box, see the EthoVision XT Help.

Notes:

• If you want to stop a trial after a specific time has been reached, refer to the relevant stop trial documentation.
• If you track from video files, see the note Tracking from video files under Apply Trial Control to your trials.
• The format for clock time is hh:mm:ss where: hh = hours, 24-hour format with leading zero; mm = minutes with leading zero; ss = seconds with leading zero.
• If you choose clock times, be aware of changeover between wintertime and summertime (Daylight Saving Time, DST) and vice versa. For example, the time 02:30:00 is encountered twice on the day of onset of wintertime (in which case the first occurrence makes the condition true), or never on the day of onset of summertime.
• If you create a condition to stop a trial after a specific time, say two hours, and within that time interval a changeover between summertime and wintertime (or vice versa) occurs, the trial lasts two hours as planned.
• The Infinite time option is useful in the following cases:
  • When you want to stop tracking manually. Place the resulting box immediately to the left of the Stop track box.
  • When two sequences have been placed in parallel, and you want the program to take further actions when Sequence 1 has been completed, independent of Sequence 2. Place a Time condition with the Infinite time option immediately to the right of Sequence 2. Combine Sequence 1 and the Time box with an Any operator.

Important: If you combine an Infinite time condition with an All operator, the program does not go further in the Trial Control rule, as it waits forever for the condition to be met.

Conditions Based on a Time Interval

A Time interval condition makes sense when it is combined with another condition. For example: take an action when the animal is found in Zone A (In zone condition) between 5 and 10 minutes (interval condition).

1. In the Components pane, double-click Time interval or click the button next to it. The Time interval Condition window opens.
2. Under Name, enter a Condition Name.
3. Under Condition is met, select one of the following:
   • Between. Define an interval between two time points (x and y seconds, minutes, or hours). Enter the time values and choose the time units. Note: The time points are counted from the time that the condition box becomes active, not from the start of the trial or tracking.
   • Between clock times. Define an interval between two absolute time points. For example, stop the track when the rat is in quadrant A between 12:00:30 and 12:01:00. The time format is hh:mm:ss where hh = hours, 24-hour format with leading zero; mm = minutes with leading zero; ss = seconds with leading zero.
4. Insert a Comment (optional) and click OK.
5. The Condition box appears in the upper-left corner of the Trial Control screen. Insert it in the appropriate position in the Trial Control sequence. For how to do this, see the EthoVision XT Help.

Notes:

• Combining Time interval and Zone conditions. In a conditioning experiment, the researcher wants to drop a food reward when the animal is found on its shelter some time between 30 s and 60 s from the previous action (for instance, a cue light being switched on). To do this, a Time interval condition must be defined that specifies the interval between 30 s and 60 s. This condition must be met at the same time as the condition "subject on shelter" in order to drop a food pellet. Therefore, the two condition boxes must be placed in parallel with an operator of type All.
• Be aware when using Time interval conditions combined with operators of type All. If the animal enters a zone after the upper time limit, the condition is never met, and Trial Control does not progress.

Conditions Based on a Trial Control Variable

A condition based on a Trial Control variable is essentially the comparison between a Trial Control variable and a value, another variable, or a formula at the time the condition becomes active and is evaluated.

1. In the Components pane, under Conditions, double-click Trial Control variable or click the button next to it.

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