Directions of unconstrained dipole orientations

[ldemoel]

Hi!

After using the MN imaging with 'dSPM standardisation' and 'unconstarined dipole orientations', the following results are plotted for the scout 'Thalamus'.

I was wondering which directions corresponds to which number. Am I right that L.1 = Left thalamus x-direction, L.2 = Left thalamus y-direction, and L.3 = Left thalamus z-direction?

And is it possible to visualize this in the MRI/scout? So what would be the x,y,z direction?

Thanks in advance!

Kind regards,
Lisanne

[Raymundo.Cassani]

Hi Lisanne,

@ldemoel

Am I right that L.1 = Left thalamus x-direction, L.2 = Left thalamus y-direction, and L.3 = Left thalamus z-direction?

So what would be the x,y,z direction?

Yes, the numbers 1, 2 and 3 indicate the x, y and z components in the subject coordinate system (SCS) respectively.

@ldemoel

And is it possible to visualize this in the MRI/scout?

• Right-click on the dSPM sources, then select Display on MRI (3D).
• Switch to the Scout tab
• Select the Volume atlas that contains the Scout from the drop-box menu
• Select the desired Scout(s) from the list, and press on the button (Show only the selected scouts) on the right.

Best,
Raymundo

[ldemoel]

Thank you!!

[ldemoel]

Can you then assume that the activity shown in the figure corresponds to the direction in which it is measured? Since the magnetic field is perpendicular to the electric field.

Thanks in advance

[Raymundo.Cassani]

@ldemoel

Can you then assume that the activity shown in the figure corresponds to the direction in which it is measured?

For unconstrained sources, the source activation shown in the figures corresponds to the norm:
S = sqrt(Sx^2 + Sy^2 + Sz^2)

More info in this link:

https://neuroimage.usc.edu/brainstorm/Tutorials/SourceEstimation#Unconstrained_orientations

[ldemoel]

Sorry to bother you again, so can I say that the activity visible in (seeing the figure from the post above) the L.1 and R.1 (the x-direction) is from the origin to the nasia?

So from the thalamus to the anterior cingulate cortex and the prefrontal cortex?

Thanks!

[Francois]

@ldemoel

Sorry to bother you again, so can I say that the activity visible in (seeing the figure from the post above) the L.1 and R.1 (the x-direction) is from the origin to the nasia?

To visualize the axes (X=red, Y=green, Z=blue): open any 3D figure, right-click > Figure > View axis.

L1 and R1 correspond to the amplitude along the red axis.

So from the thalamus to the anterior cingulate cortex and the prefrontal cortex?

Note that this indicates the orientation of the dipoles within a specific brain tissue, it does not indicate that there is current flowing or any form of connection from the cingulate cortex to the prefrontal cortex.