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fScan Reference Manual, Chapter 1 (Topics): Tutorial
Step 5: Running ttests
For more information, see Running ttests
Sam had a scan performing language tasks, with alternating blocks of sense and nonsense sentences.The task timing has already been linked to the functional files (for more information on linking behavioral data and timing information, see paradigm files), so the next step is to open an activation map. This can be done straight from a command line, or by creating a task timing name (See Tasknames). For the purpose of this tutorial, you will create a task name which is a faster way to create the same activation again and again.
5.1 In your directory, open a text window.
5.2 Type in: -r 24 24 delay 4.5 -ttest 1 2
*Note:To break down the parts of this command:
- -r finds the appropriate timing information (To make a reference file with a complete timing schedule, see here).
- delay takes into account the natural delay of a scanner and places the ttest analysis at a more appropriate starting point
- the ttest command opens the activation map, and 1 and 2 refers to the first and second tasks being analyzed. The activation map will compare all the differences in the activation of the first task with the activation of the second.
5.3 Save this text file as Language.fscan.
5.4 Open Aligned.wdf again on fscan.
5.5 Open a command line and type: -set taskname Language. This will set the default task of the dataset to Language.
5.6 Go to the File taskbar and select the dataset header icon. A window will open. Scroll down, and the section labeled Task should be set to Language.
5.7 Select Bia3_7335_1_6 and then go to the Stats viewbar and hit the 'Autotask' icon. An activation map will appear immediatly. Anytime you want to open this activation map, simply select the autotask icon. As long as the Taskname in the header is set to Language, Autotask will run the timing reference you created in Language.fscan.
5.8 Click F to clean up the activation map.
5.9 Click F7 to set the standard ttest threshold level (+4.0,-4.0).
5.10 Open the anatomical image bia3_7335_1_400 and change it to a tiled-format from the View taskbar.
5.11 Overlay the activation map on top of it. The resulting image will showcase the activation map (in green and yellow) over the grayscale anatomical image. The yellow refers to the first task and the green refers to the difference in activation from the first and the second task.
See Also:
