Simulate dipoles in 3D scouts

Discussions
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1

Dear Francois,

I ve just downloaded the latest brainstorm version

I need to simulate sources at certain 3D grid locations; for now, I use only individual grid points, no need to grow 3D scouts, also no need for noise addition.

  1. I duplicated an Ecog subject (volumetric source grid, unconstrained) to do simulations, with its forward model
  2. Added a Simulation condition to the subject by using the process Simulate generic signals
  3. I need to generate 3D scouts from individual grid points of interest

a. the cross in the Scout menu does not seem to work when I display sources on the MRI 3D, as suggested in the April 3D scout update; I click at certain points but nothing happens, no scout is generated. How do I go about it?
b. even if I make a work, some grid points may be hard to click on, I would like to be able to modify the generated scout file and input the vertex no or GridLoc coordinates for the point(s) of interest. Where is the scout file located, also please advise.
c. if a and b work, how do I link the generated scout/source to the Simulation time series, before simulating the recording and inverting?
related, is there a way to generate random scouts (each a noncontiguous 3D grid point) in the 3d grid, specifying perhaps the number of scouts to be generated?

Thank you,

Octavian

2

Dear Octavian,

a) To create a volume scout, you have to create a new “atlas” specifically designed for that. Display the sources (Right-click > Display on MRI (3D)), then in the scout tab select menu Atlas > New atlas > Volume scouts. Then move the one MRI slice where you want to create your scout, click on the [+] button to create a new scout, point on the slice. You may now see the scout seed, as it could be on the other side of the scout, just grow the scout so you can see it.

b) You can edit the 3D scout after you created it (only in a “Volume atlas”). Create a scout anywhere, select it in the Scout tab, menu Scout > Export to Matlab > “s”. Then edit the fields s.Vertices, s.Seed and s.Label, to select the sources indices you want. Then menu Scout > Import from Matlab > “s”. You should see your new scout added both in the scouts list and in the 3D figure.

c) The scouts are matched with the simulated signals in the order they appear in the interface. If you have 3 signals in your file, you need to select 3 scouts from the list.

c-bis) There is no function yet that generates a random number of scouts on volume grids.

Cheers,
Francois