Tutorial 9: Select files and run processes
Authors: Francois Tadel, Elizabeth Bock, Sylvain Baillet
Selecting files to process
First thing to do is to define the files you are going to process. This is done easily by picking files or folders in the database explorer and dropping them in the empty list of the Process1 tab.
- Drag and drop the following nodes in the Process1 list: Right/ERF (recordings), Right (condition), and Subject01 (subject)
- The number in the brackets next to each node represents the number of data files that where found in each of them. The node ERF "contains" only itself (1), Subject01/Right contains ERF and Std files (2), and Subject01 contains 2 conditions x 2 recordings (4).
- The total number of files, ie. the sum of all those values, appears in the title of the panel "Files to process [7]".
- The buttons on the left side allow you to select what type of file you want to process: Recordings, sources, time-frequency, other. Now select the second button "Sources". All the counts are updated and now reflect the number of sources files that are found for each node.
- If you select the third button "Time-frequency", you would see "0" everywhere because there are no time-frequency decompositions in the database yet.
Now clear the list from all the files. You may either right-click on the list (popup menu Clear list), or select all the nodes (holding Shift or Crtl key) and then press the Delete key.
Select both files Left/ERF and Right/ERF in the tree (holding Ctrl key), and put the in Process list. We are going to apply some functions on those two files. You cannot distinguish them after they are dropped in the list, because they are both referred as "ERP". If at some point you need to know what is in the list, just leave you mouse over a node for a few seconds, and a tooltip would give you information about it. Just like in the database explorer.
Selecting files in the database
Authors: Francois Tadel
When you have lots of files in a folder, like multiple source reconstructions of time-frequency files for each trial, it is difficult to grab just the ones you are interested in. Two mechanisms can help you: the Filter box and the process "File > Select files with tag".
Filter text box
You want to select only the averages in the data files in the protocol TutorialRaw. Drag and drop all your files there, then use the Filter search box at the bottom-right of the Brainstorm window. Type the string "Avg" to keep only the files that contain this string.
The options offered in the Filter menu are:
Search comments: Look for the string in the comments of the files, ie. what is displayed in the database explorer to represent them (the .Comment field)
Search file names: Look for the string in the full file names (including their relative path)
Select files: Only the files that contain the string are selected
Exclude files: Only the files that DO NOT contain the string are selected
Reset filters: Removes the current file filters applied on Process1 and Process2
Case insensitive: Note that the search is not sensitive to case. If you try to select the constrained sources using the string "Constr" in the comments, it would return all the files, because this matches at the same time "Constr" and "Unconstr". But you can do the opposite instead: exclude the files that contain "Unconstr".
Process: Select files with tag
You can get to the exact same result by adding the process "File > Select files with tag" before the process you want to execute, to keep only a subset of the files that were placed in the Process1 list. It is less convenient in interactive mode because you don't see immediately the effect of your file filter, but it can be very useful when writing scripts.
To see the list of files that was selected by the process, you can open the report viewer (File > Report viewer). This lists the input files (all the files) and the final files (the selected files), with a summary of how many files where selected on the top.
After
This process is useless if it is not followed immediately by another process that would do something with the selected files. An application can be the deletion of some files, by adding the process "File > Delete files".
How to control the output file names
If you are running two processes with different parameters but that produce exactly the same file names and file comments, you wouldn't be able to select them with this process. But immediately after calling any process, you can add the process "File > Add tag" to tag one specific set of files, so that you can re-select them easily later.
Example: you run twice the time-frequency decomposition with different options on the same files, tag the files after calculating them with different tags.
The main window includes a graphical batching interface that directly benefits from the database explorer: files are organized as a tree of subjects and conditions, and simple drag-and-drop operations readily select files for subsequent batch processing. Most of the Brainstorm features are available through this interface, including pre-processing of the recordings, averaging, time-frequency decompositions, and computing statistics. A full analysis pipeline can be created in a few minutes, saved in the user’s preferences and reloaded in one click, executed directly or exported as a Matlab script.
The available processes are organized in a plug-in structure. Any Matlab script that is added to the plug-in folder (brainstorm3/toolbox/process/functions/) and has the right format will be automatically detected and made available in the GUI. This mechanism makes the contribution from other developers to Brainstorm very easy.
Creating a pipeline
List of processes
- Click on Run. The Process selection window appears, with which you can create an analysis pipeline (ie. a list of process that are applied on the selected files one after the other). The first button in the toolbar shows the list of processed that are currently available. If you click on a menu, it's added to the list.
Some menus appear in grey (example: Sources > Spatial smoothing). This means that they are not meant to be applied to the type of data that you have in input, or at the end of the current pipeline. The "spatial smoothing" process may only be run on source files.
- When you select a process, a list of options specific to this process is shown in the window.
To delete a process: Select it and press the Delete key, or the big cross in the toolbar.
- With the "up arrow" and "down arrow" buttons in the toolbar, you can move up/down a process in the pipeline.
- Now add the following processes, and set their options:
Pre-process > Band-pass filter: 2Hz - 30Hz
- In some processes, you can specify the type(s) of sensors on which you want to apply the process. This way you can for instance apply different filters on the EEG and the MEG, if you have both in the same files.
Extract > Extract time: 40.00ms - 49.60ms, overwrite initial file
- This will extract from each file a small time window around the main response peak.
- Selecting the overwrite option will replace the previous file (bandpass), with the output of this process (bandpass+extract). This option is usually unselected for the first process in the list, then selected automatically.
Average > Average over time: Overwrite initial file
- Compute the average over this small time window.
Save your pipeline: Click on the last button in the toolbar > Save > New... > Type "process_avg45".
Saving/exporting a pipeline
The last button in the the toolbar offers a list of menus to save, load and export the pipelines.
Load: List of processes that are saved in the user preferences
Load from file: Import a pipeline from a pipeline_...mat file (previously saved with the menu "Save as Matlab matrix")
Save: Save the pipeline in the user preferences, to be able to access it really fast after
Save as Matlab matrix: Exports the pipeline for a Matlab structure in a .mat file. Allows different users to exchange their analysis pipelines (or a single user between different computers).
Generate .m script: This option generates a human-readable Matlab script that can be re-used for other purposes or modified.
Delete: Remove a pipeline that is saved in the user preferences.
Reset options: Brainstorm saves automatically for each user the options of all the processes. This menu removes all the saved options, and set them back to the default values.
Here is the Matlab script that is generated automatically for this pipeline.
Click on Ok, in the pipeline window. After a few seconds, you will see two new files in the database, and the "Report viewer" window.
Report viewer
Each time the pipeline editor is used to executed to run a list of processes, a report is generated and saved in the user home folder (/home/username/reports/). The report viewer shows as an HTML page some of the information saved in this report structure: the date and duration of execution, the list of processes, the input and output files. It reports all the warning and errors that happen during the execution.
The report viewer does not necessarily appear automatically at the end of the last process: it is shown only when more than one processes were executed, or when any of the processes returned an error or a warning.
When running processes manually from a script, the calls bst_report(Start, Save, Open) explicitly indicate when the logging of the events should start and stop.
You can add images to the reports for quality control using the process "File > Save snapshot".
After you close the report window, you can re-open the last report with the main menu of the Brainstorm window: File > Report viewer.
With the buttons in the toolbar, you can go back to the previous reports saved from the same protocol.
PROCESSES AND PLUG-INS
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