Editing Channel Locations

In order to perform operations such as Topographic Interpolation or viewing topo maps in Mapping View, you will need in to import your own channel locations so the channels analyzed in the data set are in the same orientation as how you collected the data. BVA by default does not have any preset channel orientations. Channel locations can be imported to only be applied to a specific data set or can be imported as default channel locations that can be saved for future use.

Coordinate files

Coordinate files that are accepted in BVA are .bvef files. For the EGI HydroCel GSN 256-channel coordinate .bvef file, e-mail Edward Lau (eplau@ucla.edu) or Sam O'Connell (samroconnell@gmail.com) to obtain the files. For other configurations, feel free to e-mail BVA support at support@brainproducts.com.

Coordinate files can be created by the user if you know the radial, theta, and pi coordinates of the electrodes in the array that the data were collected. By choosing Edit Channels under the Transformations tab, these values can be inputted for each channel in the table. After inputted, by choosing Save Positions to File in the lower right corner of the screen, you can save these coordinate settings into a .bvef file; however, if not certain that these are the coordinates, creating your own .bvef file can be risky and may not give you the topographic results you were hoping to see, so we suggest contacting BVA support to see if they have a ready-made .bvef file for your particular net. Otherwise, contact Edward Lau and he may be able to help.

Importing Default Channel Locations

1. Under the File tab, choose Preferences
2. In the Preferences window, choose the Electrodes tab
3. Under the Electrodes tab, it asks for the Default Coordinate File. Choose Browse and find the .bvef file you would like as your default coordinate file.
4. Press OK and the default file should be saved for all times you open BVA.

Applying Channel Locations to a Data Set

1. Under the Transformations tab, choose Edit Channels.
2. In the bottom right of the window, you will see a Positions section.

• To load new positions from a file, select Load Positions from File and select the file that you would like to .bvef file you like to apply to the data set
• To load default positions, select Default Positions. A window will ask you if you really want to set all channel coordinates to default positions. Select yes and the default positions will be loaded in. See above to set default coordinate locations.

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