Knowledge Base

13 Data Preparation

Smooth The Tracks

Track Smoothing profiles in the template experiment

No Smoothing. Smoothing filters are not activated.

MDM 0.2 mm - With this Minimal Distance Moved filter, you can

reduce the effect of 'jitter' on the Distance moved variable. Applying this filter is recommended, however, it results in longer calculation times in the analysis. Change these settings for your setup, if necessary.

More options

Use the Maximum Distance Moved filter to remove outliers in the track, due to erratic detection of objects within the arena. when the margin of the well is sometimes detected as the fish.

For more information on smoothing data, see Smooth the Tracks in the

EthoVision XT Help.

Select Data

Data profiles in the template experiment

All Data. With this Data profile you analyze all tracks separately.

Treated vs. Control - The data are split for analysis based on the two

values of the user-defined variable Treatment: Treated and Control.

Analyze dark vs. light periods

In this example, the researcher wants to analyze the data in different light and dark periods, determined by the activation of the white light.

In the Data profile, the function Trial Control State under Nesting is

used to create intervals corresponding to the state of the white light. 1. Choose Analysis > Data Profile > New. Give the new Data profile a name and click OK. 2. In the Components pane, under Nesting, click the button next to Trial Control State. 3. Select the period you are interested in, using the Trial Control

actions. For example From Light On To Light Off (depending on what

name the Light On/Off actions have in the Trial Control Settings). 4. Insert the Nest box in the Data profile sequence. 5. If you want to analyze different periods and have the results in the

same table, create more Results boxes as shown in the picture

below. To add a Result box, in the Components pane click the button

next to Result. In each sequence, add a Nest box that specifies a

different Trial Control State. 6. Choose the dependent variables and run analysis (see page 113).

tip See also the sample experiment DanioVision with 96 wells XT

which you can download from our web site. There you can find the Data profile mentioned here.

Analyze data excluding periods of inactivity

In this example we want to exclude the interval in which a larva was not moving. 1. Choose Analysis > Data Profile > New. Give the new Data profile a a name and click OK. 2. In the Components pane, under Nesting, click the button next to Movement. 3. In the Movement tab, you can set the following:

Averaging interval (range 1 - 1000) - This is the number of

samples across which changes in speed are calculated to determine whether the subject is moving or not. In order to reduce the sensitivity of the Movement variable to brief changes in velocity, the velocity data can be smoothed by taking the running average of the last n samples. Enter the averaging interval n or leave 1 if you do not want to smooth the velocity data.

Start velocity - The velocity above which the subject is

considered to be moving.

Stop velocity - The velocity below which displacements of the

subject's body points are no longer attributed to locomotion but to system noise, body wobble or pivoting on the spot. 4. Under Calculate nesting for, select Not moving. 5. Click OK. Insert the Nest box in the appropriate position between the Start and the Result box. 6. Choose the dependent variables and run analysis (see page 113).

For more information on the Nesting functions, see Analyze Track

Segments in the EthoVision XT Help.

Analyze the intervals around the onset of the white light

In this example, we want to analyze two intervals: From 5 seconds before the onset of the White light stimulus, to the onset of the stimulus. From the onset of the White light stimulus, to 5 seconds after the onset of the stimulus. The aim is to compare activity, speed and other parameters between the two intervals. 1. Choose Analysis > Data Profile > New. Give the new Data profile a a name and click OK. 2. In the Components pane, under Nesting, click the button next to Free interval. 3. Do the following:

Under Start criterion, select Trial Control. Choose the options as in

the picture below.

Under Stop criterion, select Time. Next to Elapsed time leave

0:00:00.000 after start event selected.

note "Start event" here refers to the White light selected under

Interval start. Click OK and insert the Nest box in the sequence. 4. To create the second interval, choose first Result under Common

elements. Click the middle of the Start box and drag to the Result 2

box; this will connect the two boxes. 5. Repeat the steps 2-3 to create a new Nest box, this time for the interval "from White light to 5-s after that". In the settings, choose the criteria for the second interval: from "Trial Control - 0 seconds before Action: Light on" to "Time - Elapsed time 5 seconds after start event". Click OK and insert the Nest box in the sequence. 6. Choose the dependent variables and run analysis (see page 113).

tip Click Settings in the Result boxes and rename them, to for example

"5-s Before white light" and "5-s after white light". Those names will be shown in your results.

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Source: Reference Manual - DanioVision DVOC-0041