Dear community,
I have a question regarding the connectivity on the source space.
I would like to compte different metrics of connectivity (mainly coherence and AEC), I have a question regarding the source reconstruction measure.
Since I wanted to compute the connectivity, should I employ the CSD, dSPM or sLoreta ?
If I corrected understand, dSpm and sLoreta are some ways to normalize the CSD, and this approach should not be employed for frequency representation.
In general it is better to measure the CSD for connectivity purpose ?
Thank you
Bests
Alex
The normalizations dSPM and sLORETA do not affect the frequency information of the signal, just the relative amplitude scaling between different sources in the brain. For one given source, the dSPM signal is the min norm current density multiplied by a constant factor.
Therefore it should not affect much the time-frequency or connectivity estimation. However as a normalization is not required for these measures, it is better not to apply any additional transformation to the min norm current density maps.
I think the recommendations in the introduction tutorials are clear:
https://neuroimage.usc.edu/brainstorm/Tutorials/SourceEstimation#Typical_recommendations
Thank you @Francois for you answer.