Knowledge Base

Analysis of Trial Control Data

What Do You Want to Do?

Trial Control data are analyzed as Dependent variables. Choose your dependent variables in the Analysis Profile.

Analyze Events That Occurred During the Trial

How many times a condition became true? How many times the food reward was given? What is the latency of the first reward? To answer these questions, we consider the events associated with single Trial Control boxes. See Trial Control Events below.

Analyze the Time Defined by Two Events

How much time elapsed from the moment the cue light switched on to when the subject entered the reward zone? See Trial Control States.

A special case in this category is the analysis of learning. Did the time between the event Light on and the event Subject in reward zone decrease during the test?

Analyze the Data Within the Time Between Two Events

How many times a certain behavior occurred when the stimulus light was on? What was the speed of the subject between event A and event B? To answer such questions, use the Nest function to define the time segments within which the event or behavior of interest occurred. See Analyze the Data Within Trial Control States.

Analyze Trial Control Variables

A Trial Control variable has been defined in the Trial Control procedure. Its value is increased every time the subject makes a correct choice. To analyze the performance of the subjects, calculate the maximum value of the variable, and visualize when the maximum value occurred. See Trial Control Variables.

Analyze the Commands Sent to Hardware Devices

How many times did EthoVision XT send a command to a pellet dispenser to drop one pellet? See Hardware Command.

Analyze Variables Associated With Hardware Devices

For example, analyze the data from the Lickometer. For hardware devices, there are continuous variable and state variables. See Hardware Continuous Variable and Hardware State Variable.

Notes

• For more general information on analysis variables, see Dependent Variables in the EthoVision XT Help.
• To visualize Trial Control data, from the Analyze menu, select Results and then Plot Integrated Data (see the EthoVision XT Help).
• To export Trial Control data, see the Export section.
• Trial statistics of Duration and Latency can only be a multiple of the sample interval (= 1/sample rate). For example, a condition like Subject in zone A for >= 3 s is met when the time elapsed from its activation exceeds 3 s. If the sample rate is 12.5 frames/s (sample interval = 1/12.5 = 0.08 s), the condition is met at the first multiple of 0.08 greater than 3 s, that is 3.04 s. For this reason, the latency of the event Condition becomes true is 3.04 s.

Trial Control Events

If you are interested in the rate of events such as the number of times the lever was pressed, the number of pellets dropped, or the latency of an action, use the Trial Control event function in the Analysis Profile.

1. In the Experiment Explorer, right-click Analysis Profiles and select New, or click an existing profile.
2. In the Dependent Variables pane, under Trial Control, double-click Trial Control event, drag it to the middle of the screen, or click the button next to it.
3. The Trial Control event window appears. Under Event, from the Element list select the element to be analyzed. For example, to analyze the hardware-based action Drop pellet, locate it among Action: Drop pellet and select it.
4. From the Event list, select the event for the element selected. The options available depend on what you have chosen as Element (see Possible Events of Trial Control Elements below).
5. Click the Trial Statistics tab and select the statistic you want to analyze.
6. Click the Group Statistics tab and select additional statistics if you want summarized statistics over all trials, or the groups of trials defined in your Data Profile.
7. Click Add. The new Trial Control event appears in the list of Selected Dependent Variables.
8. Choose the option you require:
   • To calculate statistics of the selected events, choose Analyze > Results > Statistics & Charts.
   • To visualize the events, choose Analysis > Results > Plot Integrated Data.

Notes

• If one or more other instances of Trial Control event are listed under Selected Dependent Variables, the Trial Control event name is followed by a progressive number (1, 2, 3...).
• The Element list contains the Trial Control elements defined in all your Trial Control Settings. For each element, the list shows the name of the corresponding Trial Control box.
• Choose Latency to first to analyze the time of the first instance of the event defined since the start of tracking. Choose Latency to last to analyze the time from the start of data recording to the last instance of the event defined.
• For calculating frequency and latency of the subject's behavior, choose the appropriate Dependent Variable (see Dependent Variables in Detail in the EthoVision XT Help).

Possible Events of Trial Control Elements

• Becomes active (for Start-stop trial rule begin, sub-rule begin, conditions, actions, references and operators). Marks the time that the trial starts (for the Start-stop trial rule begin) or the element becomes active (in all other cases). This is the time when control passes from the previous box in the Trial Control sequence. See the notes below for the difference between Becomes active and Becomes true.
• Becomes true (for conditions and operators). Marks the time that a condition is met. Choose this option for example to analyze the instances when the condition In zone A was met.
• Becomes false (for conditions and operators). Marks the time that a condition is not met. Choose this option for example to analyze the instances when the condition In zone A was not met.
• Becomes inactive (for Start-stop trial rule end, sub-rule end, conditions, actions, references and operators). Marks the time that the element becomes inactive, that is, when control passes to the next box in the Trial Control sequence.

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