Dear Vladimir,
With regard to hidden source, I still have several simple questions. In the paper(David O, etc. 2011) you recommended to me the last time, David specify the hidden source's coordinate as [0 0 0]. However, you suggest that we can specify the position further that 200mm from the origin (like [300 300 300]). Are there any differences between [0 0 0] and [300 300 300]?
I don't know whether this is ture or not: as for any subcortical regions, if I want to specify them as hidden sources, I just need to plus 200mm to their coordinates respectively(e.g. Cingulate [0 36 28] , change to [200 236 228] )?
Further, could I specify two or more hidden sources in my model? If so, how can I specify the coordinates for them? Set both of them to [0 0 0] or others?
Thank you!
Best wishes to you!
Haoran.
At 2011-06-11 00:56:11，"Vladimir Litvak" <[log in to unmask]> wrote:
>Dear Haoran,
>
>There are two answers to that. The first answer is that whether there
>is any signal in the MEG from amygdala or hippocampus is subject to
>debate and there is some evidence in favor of that but it's not
>conclusive. The second answer is that you can include sources in your
>DCM model even if there is no signal in the MEG/EEG from these sources
>and learn something about those 'hidden' source from their
>interactions with sources that are observed. As an example you can
>look at http://www.ncbi.nlm.nih.gov/pubmed/21325540 . You can either
>just place sources e.g. in the hippocampus the usual way or (in an
>up-to-date SPM) if you specify the position further that 200mm from
>the origin (like [300 300 300]) the lead field of the source will be
>set to zero and then it will be truly hidden source. You can compare
>the two ways with model comparison to see if there is really any
>evidence for the source being at particular location or not.
>
>Best,
>
>Vladimir
>
>2011/6/9 飞鸟 <[log in to unmask]>:
>> Dear spm's users,
>> Thanks for your concern! As DCM for EEG/MEG is based on nerual mass model,
>> I wonder that can I apply DCM for EEG/MEG to cerebral limbic system( such as
>> cingulate, hippocampus and amygdala etc). In other words, is it valid to
>> specify my model not only include cortex regions(e.g. frontal lobe, temporal
>> lobe etc.), but also include cingulate or other limbic system's regions?
>> Any help will be appreciated!
>>
>> --
>> Haoran LI (MS)
>> Brain Imaging Lab,
>> Research Center for Learning Science,
>> Southeast University
>> 2 Si Pai Lou , Nanjing, 210096, P.R.China
>>
>>
--
Haoran LI (MS)
Brain Imaging Lab,
Research Center for Learning Science,
Southeast University
2 Si Pai Lou , Nanjing, 210096, P.R.China
