[Eeglablist] How are units in SIFT connectivity outputs created from model coefficients?

James Jones-Rounds jj324 at cornell.edu
Thu Jul 30 11:57:46 PDT 2015

Hello all,

Looking thoroughly through the SIFT manual, and related references online,
I'm having trouble seeing definitively how the (unit-less?) SIFT
connectivity estimation, specificaly dDTF and rPDC, are converted to
Spectral Density or Decibels.

Can anyone give a summary, or point to a reference ( if possible, for
non-mathematicians), that describes a little more about how the final
output, in the EEG.CAT.Conn fields, results from the coefficients of the
MVAR model?

We typically check yes to convert spectral density to dB, when running
SIFT, and I see in the SIFT documentation that the spectral density matrix
and transfer function are obtained from the autoregressive model
coefficients. But we really want to be sure of what those final
(non-unit-less) values represent before we start manipulating them for the
purposes of group analysis and publication.

Thank you anyone who can provide some insight!


James Jones-Rounds
Laboratory Manager
Human Development EEG and Psychophysiology (HEP) Laboratory,
Department of Human Development,
Cornell University | Ithaca, NY
eeg at cornell.edu
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sccn.ucsd.edu/pipermail/eeglablist/attachments/20150730/0a8c6d29/attachment.html>

More information about the eeglablist mailing list