[FieldTrip] Source Analysis

Eelke Spaak eelke.spaak at donders.ru.nl
Fri Dec 6 16:07:24 CET 2013


Hi Azeez,

For your question (1), I think it would be helpful if you give a bit
more information on what you are doing. If the source reconstruction
is not aligned to your MRI, probably some ingredient for the source
analysis was also misaligned. Could you see whether your source model,
volume conduction model, and sensor definition are all in alignment?
(See here http://fieldtrip.fcdonders.nl/faq/how_can_i_check_whether_the_grid_that_i_have_is_aligned_to_the_segmented_volume_and_to_the_sensor_gradiometer
)

Regarding (2): typically I would use cfg.taper = 'dpss' (the default)
and then choose a combination of cfg.foi and cfg.tapsmofrq that yield
the frequency band of interest. E.g. cfg.foi = 20 and cfg.tapsmofrq =
8 gives you a frequency band ranging from 12 to 28 Hz.

Best,
Eelke

On 5 December 2013 20:32, Azeez Adebimpe <ayobimpe2004 at hotmail.com> wrote:
>
> hello,
>
> 1. I used ASA head model to projected electrode on it  to calculated the
> lead field and perform source analysis. I ma having problem with the
> projection of source on MRI after source interpolation.  The source couldn't
> align with the  MRI image. The first picture is  for the source (before
> interpolation) and the second is after interpolation. I have tried several
> methods like volumeresclice but no good result. Please help me!
>
>
> 2. I want to do source analysis in frequency band (like alpha, beta  etc)
> with frequency analysed data (ouput of ft_frequencyanalysis). But in the
> source analysis, I can only select one frequency (not band). Please I how
> can I play with it to get the frequency range of interest?
>
> Best regards,
> Azeez Adebimpe
>
>
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