[Eeglablist] Can Dipfit 3.0 (LORETA) only fit dipoles to selected time points or does it create source space time series?

[Kaelasha Tyler]

Hi Arno and others,

I want to find the best way to calculate averaged time series data within a
ROI after using eLORETA.
Can anyone help with this?
(I have been successfully using the following wiki and FieldTrip code on
data originally preprocessed in EEGLab:
https://sccn.ucsd.edu/wiki/A08:_DIPFIT#Performing_source_reconstruction_in_a_volume
)

*Are there any simple maps or references of which anatomical grid points
(produced by eLORETA and ft_sourceanalsysis) to be included in a given
standard ROI?*

For example, if I wanted to average time series data occurring at all
anatomical points in the left auditory cortex, and my eLORETA has produced
a grid of 15 x 18 x 15 points using a template MRI, is there any index of
which of these grid points belongs to the left auditory cortex?

If so, can I just manually average the time series data across those grid
points, and would that be the simplest option?

Or does the solution to data averaging within ROIs need to be a bit more
sophisticated than that?
------------------

Previously Arno, you recommended modifying the following code to my
purposes:

https://github.com/arnodelorme/roiconnect

This may work, but if there is an index of which source grid points
correspond to various standard ROIs, would the above aproach work just as
well? It would certainly be simpler.

P.s. my end goal is to calculate cross frequency analysis on time series
data averaged within ROIs.

Thanks in advance,
Kaelasha











On Wed, Feb 5, 2020 at 11:48 AM Kaelasha Tyler <kaelasha.tyler at gmail.com>
wrote:

> Great, thanks Arno.
>
> I will go with the eLoreta across time method that you mentioned, and then
> do cross frequency analysis on that data separately.
> I have used Fieldtrip before, so this looks to be similar.
>
> The experimental plugin with Stefan Haufe looks good. But I will save that
> for another time.
>
> Cheers!
>
> Kaelasha
>
> On Wed, Feb 5, 2020 at 3:36 AM Delorme, Arnaud <adelorme at ucsd.edu> wrote:
>
>> Dear Kaelasha,
>>
>> > My question is, can Dipfit 3.0 be used to reconstruct EEG time series
>> > within the anatomical ROI, or does Dipfit 3.0 only fit dipoles at
>> selected
>> > timepoints?
>>
>>
>> There is some code on the page you are mentioning that allows to look at
>> eLoreta across time in 3-D
>>
>>
>> https://sccn.ucsd.edu/wiki/A08:_DIPFIT#Performing_source_reconstruction_in_a_volume
>>
>> Also, this can be done using the ERPsource EEGLAB plugin
>>
>> https://github.com/sccn/erpsource
>>
>> > I am wanting to look at cross frequency coupling at specific regions of
>> > interest within the brain.
>> >
>> > For this, I thought to reconstruct the EEG time series in the ROIs and
>> then
>> > do further frequency analysis on that data set, to asses levels of cross
>> > frequency coupling in different ROIs across different conditions.
>>
>> There is also this other experimental plugin on which I worked on with
>> Stefan Haufe
>>
>> https://github.com/arnodelorme/roiconnect
>>
>> It does not do cross-frequency coupling though - only within frequency
>> coupling between brain regions. The code could be modified to do
>> cross-frequency though because this plugins does the heavy lifting by
>> performing ROI eLoreta.
>> For cross-frequency coupling in specific region of the brain, Ramon
>> Martinez in our group is currently working on a solution for EEGLAB. There
>> might be a solution in Fieldtrip already, I am not sure.
>>
>> Cheers,
>>
>> Arno
>>
>> _______________________________________________
>> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
>> To unsubscribe, send an empty email to
>> eeglablist-unsubscribe at sccn.ucsd.edu
>> For digest mode, send an email with the subject "set digest mime" to
>> eeglablist-request at sccn.ucsd.edu
>>
>