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

[Kaelasha Tyler]

Hi Eric,

Here is a link to the paper whose analysis I am replicating:
https://www.ncbi.nlm.nih.gov/pubmed/25348645

The use of Dipfit2.2 in conjunction with ICA is on page 474:

" ...The remaining components were fitted with individual inverse dipole
solutions using the DIPFIT 2.2 algorithm. Components with nondipolar
equivalent dipole solutions usually represent nonbrain signals ........and
were also removed."

This paper does not deal source localisation per se, and this use of Dipfit
is only in conjunction with removal of ICA components.

I just wasn't familiar with use of Dipfit in cases where there is no
intention to analyse source based data, and wondered how necessary it
really is?

Thanks for the help.

Cheers,
Kaelasha






On Tue, Jul 9, 2019 at 4:07 AM Eric Rawls <elrawls at email.uark.edu> wrote:

> Hi Kaelasha,
> Could you link to the paper you are trying to replicate?
> As others have mentioned, I have a hard time thinking of a use of dipole
> fitting if you are categorically not interested in source localization.
> One possibility that I saw at a recent conference (don't know if the paper
> is out yet, it was a poster presented by Sid Segalowitz) is to remove all
> ICs except those localized to certain anatomical regions, then to analyze
> the scalp projection made of only (for example) PFC generators.
> However, without knowledge of the analysis you're trying to replicate this
> is speculatory.
> You can also technically fit a dipole to the scalp map of EEG activation
> at a specific time point but this is not advisable, because many individual
> dipoles are active at each point in the time series.
> Cheers
> Eric Rawls, M.S.
> Graduate Research Assistant, Instructor
> Department of Psychological Sciences
> University of Arkansas
>
> On Mon, Jul 8, 2019 at 5:51 AM Kaelasha Tyler <kaelasha.tyler at gmail.com>
> wrote:
>
>> 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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>