Montage editor

Sensor selection

Let's switch to a nicer representation of the recordings time series: click on the "Display mode" button in the toolbar of the Record tab.

Now the traces are displayed in columns, but all the channels are displayed in the same figure, which makes it unreadable. Select a subset of channels by right-clicking on the figure > Montages, with the drop-down menu in the Record tab or with a keyboard shortcut (Shift+A, B, C...). Default groups of sensors are available for some MEG systems, but you can also create your own groups of sensors with the menu "Edit montages".

Montages

A better way to review a large number of MEG/EEG signals at once is to display only a subset of them at once. This can be done using the "montage" interface. The term refers mainly to EEG, to define the referencing system used to display the values recorded on the electrodes: bipolar montages, custom reference electrodes, average reference. However, the same interface can be used in MEG to select only a subset of sensors in a given figure, using a predefined or custom set of channels.

• Use the drop-down menu in the Record tab to several predefined sets (ex. CTF LF = Group of left frontal sensors). Alternatively, right-click on the figure > Montage. You may need to decrease again the gain of the channels (use SHIFT+Mouse wheel)

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• Note the keyboard shortcuts: SHIFT+letter. It makes it really easy to switch from a group of sensors to another (ex: Shift+A = all sensors, Shift+B = Left-frontal, Shift+C=Right-frontal...)

• To edit/create your own selections, use the menu "Edit montages". You can edit the channels selection groups or the electrodes montages available for this installation of Brainstorm. By default, it shows only the ones that are relevant to the type of recordings you are currently looking at (in this case: CTF MEG recordings). To see all the available options, click on the button "All".
• Click on "New channel selection" to create a new selection Test1, and select a few channels in the list.

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• Click on Save. Back to the time series figure. Look in the popup menu again, you can see your new selection in the menu: Test1. You can now use the time series view with those predefined selections of sensors.
• To display several montages at the same time, or with different different display options, you need to open twice the same file and then set the parameters differently. You have two option to clone the figure:

  • Do twice: Right-click on the file in the database explorer > MEG > Display time series

  • Right-click on a figure > Figure > Clone figure

  • To have the same scale in both figures, use the buttons "..." in the figures