[Eeglablist] Is dipfit ever used for purposes other than localising source space data?

[Downey, Ryan J]

If you don't plan to use ICA at all then I can't think of any purpose of using dipfit. 

If, however, you want to do analysis on channel data that has been cleaned by ICA, then you could potentially use dipfit. For example, you could run ICA on the data and then use dipfit to help you remove ICs that are artifacts and then finally reconstruct your channel level data with the bad ICs removed. But honestly, I would probably use visually assess the ICs rather than use dipfit to determine bad ICs. The reason being is that potentially you could have an ICA decomposition that wasn't perfect and contains an IC with two or more brain sources mixed together. This IC would have a bad dipole fit and could cause you to accidentally reject brain activity from your channel-level data. When cleaning channel data with ICA (i.e. not doing source analysis and clustering), I would err on the side of rejecting only ICs that are very obviously not brain (based on the spectra and time series plots) and keep ICs that could be mixtures of multiple neural sources or brain + noise. 


Ryan J. Downey
Postdoctoral Associate
Human Neuromechanics Laboratory
Biomedical Engineering Dept.
University of Florida

 

-----Original Message-----
From: eeglablist <eeglablist-bounces at sccn.ucsd.edu> On Behalf Of Kaelasha Tyler
Sent: Saturday, July 6, 2019 3:11 AM
To: eeglablist at sccn.ucsd.edu
Subject: [Eeglablist] Is dipfit ever used for purposes other than localising source space data?

Hi all,

EEG and MEG data can be analysed at the level of electrodes/sensors, or on the data as it is reconstructed back into anatomical space in the brain, using are range of processes (Beamforming, dipole fitting, LORETA etc).

*My question is: will dipfit ever be useful if you are content carrying out the analysis at the level of the electrodes or sensors (not in reconstructed anatomical space)?*

To explain:
I am replicating an analysis in the literature, and reference in the paper I am following is made to fitting dipoles using dipfit2.2. However I am not needing to calculate eeg as it wold have occurred within the brain, but am content performing the analysis on ICA components of data recorded at the electrodes.

In this case, is there any need at all to fit dipoles using dipfit2.2 ?
Does using diptfit serve any other purpose?

Thanks in advance.
Kaelasha
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