Knowledge Base

Analysis of Trial Control Data

When the animal actually enters the zone (and thus Current = true for that sample).

• If you use any other statistic to define the condition (for example, "when Frequency of In zone >= 1"):
  • When the condition becomes true after the condition box is activated, the Trial Control State starts (or stops) at the expected sample time (see A in Figure 47).
  • When the condition is already true when the condition box is activated (for example, a condition "Frequency of In zone = 1" is activated when the animal is already in the zone), such statistic is only evaluated at the next sample (or in the second next sample, in the case of Heading). In that case, the Trial Control state starts (or stops) one sample (or two) later than expected from the condition (see B in Figure 47). However, for the consecutive frequencies of In zone = 2, 3, etc., the condition is already active by definition; therefore the Trial Control State starts at the expected time, when the condition becomes true.

Figure 47: In this example, a Trial Control condition has been defined in the Trial Control Settings, which checks that the Frequency of In zone is >= 1 for the Center of the open field. A Trial Control state has been defined in the Analysis profile, which starts when the condition "Frequency of In zone >= 1" is true.

• A1 — The animal enters the Center zone (and therefore the condition becomes true) after the condition is activated. The Frequency statistic is evaluated at the same sample time.
• A2 — Plot of the variables "In zone" for the Center and the Trial Control state. The Trial Control state starts at the expected sample time, that is, when the animal actually enters the zone.
• B1 — The animal is already in the zone when the condition is activated. Therefore, the condition becomes true at the same time that it is activated, but the Frequency statistic is evaluated at the next sample (here, sample rate = 5/s, thus after 0.2 s).
• B2 — Same plot as A2; here, the Trial Control state starts 0.2 s after the In zone state.

If you de-select Calculate statistics per interval, the Cumulative duration statistic is the total duration of the intervals in that trial.

If you want to know how many occurrences of the intervals a specific trial contains, follow the procedure above making sure that Calculate statistics per interval is not selected, and Frequency is selected under Trial Statistics. 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. Next, run the analysis. The table shows the number of intervals under Frequency for that dependent variable. The occurrences are counted if the From condition is met. If the trial ends before the To condition is met, the interval is still counted in the Frequency.

Examples of Trial Control States

Example 1

In a conditioning test, it is required that the subject must go to zone A in order to receive a reward. The researcher wants to know the time from the moment the subject could have responded (Condition Subject in zone A becomes active) to the moment the subject eats the reward (Condition Subject in feeder zone becomes true).

The Trial Control sequence is as follows: Rule Begin → Condition - In zone A → Action - Drop a food item → Condition - In Feeder zone → Rule End.

In the Analysis profile, click Trial Control state and select:

• From - Element Condition: In Zone A, Event = becomes active
• To - 1st occurrence of Element Condition: In Feeder zone, Event = becomes true

In the Trial Statistics tab, make sure that Cumulative duration is selected.

Example 2

In a variant of the experiment above, the researcher wants to know the time that it takes the mouse to get the pellet after being in zone A. Here we assume that if the animal enters zone A, then gets out and subsequently gets back in before collecting the food item, one wants to analyze from the first instance that the mouse went in zone A.

In the Analysis Profile, click Trial Control state and select:

• From - Element Condition: In Shelter zone, Event = becomes true (because one wants to analyze the time from when the condition is met)
• To - 1st occurrence of Element Condition: In Feeder zone, Event = becomes true

In the Trial Statistics tab, make sure that Cumulative duration is selected.

Analyze Learning Behavior

When a sequence like Cue stimulus → Subject's action → Reward is repeated a number of times, you may want to know whether there is a trend of decreasing or increasing duration of intervals from one component of the sequence to the next. For example, is the time from the cue stimulus to the subject's lever press decreasing during a 30-minute test?

To analyze learning behavior, follow the procedure on page 180, and make sure that:

• In the Trial Control State Interval tab, select the Calculate statistics per interval option.
• Next to For consecutive intervals, select which occurrences of the interval you want to analyze.
• In the Trial Statistics tab, make sure that Cumulative duration is selected. 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.

Calculate the statistics, and export the results (see Calculate Statistics in the EthoVision XT Help).

Analyze Data Within Trial Control States

If you want to calculate statistics on or visualize data within intervals defined by Trial Control events, you must first define those intervals as Nesting intervals in the Data Profile.

1. In the Experiment Explorer, right-click Data Profiles and select New, or click one of the existing profiles.
2. In the Components pane, under Nesting, double-click Trial Control state or drag it to the middle of the screen, or click the button next to it.
3. The Trial Control state window appears. Define the interval as described in the procedure on page 180 (the options are the same, only the Statistics tab is not present).
4. Click OK. The Nest box appears on the screen. Insert this box between the Start and the Result box.
5. In the Experiment Explorer, right-click Analysis Profiles and select New, or click one of the existing profiles.
6. Define the dependent variables you want to analyze and run analysis or visualize the data.

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