[FieldTrip] extracting virtual time series in MNI space

Arjen Stolk a.stolk8 at gmail.com
Mon Mar 21 18:37:00 CET 2016


Hi Vasan,

Hard to tell based on this information, but did you copy over the
template's dim and pos fields after normalization and/or check for
(mis-)matches in geometric units (cm vs. mm) between grids and ROIs?

Arjen

2016-03-21 10:17 GMT-07:00 Sreenivasan R. Nadar, Ph.D. <
sreenivasan.r.nadar at gmail.com>:

> Hi Arjen,
>
> Thank you. I tried the method give in that link with ft_volumelookup for
> ROIs in MNI space and make a new leadfield for the ROIs  and use the
> following commands for visualization:
>
> figure; hold on;
> ft_plot_vol(headmodel, 'edgecolor', 'none', 'facealpha', 0.4);
> ft_plot_mesh(lf_new.pos(lf_new.inside,:), 'facecolor','r');
>
> However, this method doesn't work properly as the grid sometime do not
> fall in the expected anatomical location.
>
> -Vasan
>
> On Mon, Mar 21, 2016 at 12:51 PM, Arjen Stolk <a.stolk8 at gmail.com> wrote:
>
>> Hey Vasan,
>>
>> One way to do that is by 'normalizing' the subject's grid such that its
>> points relate to specific points in MNI space. The procedure is described
>> here:
>> http://www.fieldtriptoolbox.org/tutorial/sourcemodel
>>
>> Using ft_volumelookup you can subsequently find the subject's grid points
>> (now in MNI space) belonging to ROIs.
>>
>> Hope that helps,
>> Arjen
>>
>> 2016-03-21 9:40 GMT-07:00 Sreenivasan R. Nadar, Ph.D. <
>> sreenivasan.r.nadar at gmail.com>:
>>
>>> Hi Arjen,
>>>
>>> The example scripts are for on the individual "subject space". I want to
>>> do the source analysis and also extracting time series for any ROIs in MNI
>>> space.
>>>
>>> -Vasan
>>>
>>> On Mon, Mar 21, 2016 at 12:35 PM, Arjen Stolk <a.stolk8 at gmail.com>
>>> wrote:
>>>
>>>> Hey Vasan,
>>>>
>>>> This page ("Extract the virtual channel time-series" section) provides
>>>> an example:
>>>> http://www.fieldtriptoolbox.org/tutorial/connectivity
>>>>
>>>> Arjen
>>>>
>>>> 2016-03-21 9:08 GMT-07:00 Sreenivasan R. Nadar, Ph.D. <
>>>> sreenivasan.r.nadar at gmail.com>:
>>>>
>>>>> Hi All,
>>>>>
>>>>> Is there any standard procedure (in Fieldtrip) for extracting virtual
>>>>> (source) time series from ROIs in Talariach or MNI space?
>>>>>
>>>>> Thank you
>>>>>
>>>>> -Vasan
>>>>>
>>>>>
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