[FieldTrip] Estimate coherence between conditions?

[Maria Hakonen]

Hi Maria,
for obtaining the sources timecourses (aka virtual channels) you can
follow the tutorials pasted below.

Best,Maité
http://www.fieldtriptoolbox.org/tutorial/connectivity#extract_the_virtual_channel_time-series
http://www.fieldtriptoolbox.org/tutorial/shared/virtual_sensors#extract_the_virtual_channel_time-series

Hi Maité,

Thank for your answer again!

However, I would need to calculate coherence within certain frequency
bands and, therefore, I would like to use dics. The examples in the
links seem to use lcmv. Could you please let me know how I can get
coherence between conditions using dics?

Best,

Maria


2017-06-26 12:45 GMT+03:00 Maria Hakonen <maria.hakonen at gmail.com>:

> Hi Maria,
> maybe in this case it is better that you export the sources timecourses, build a data matrix with them and treat them in the same way as you did with the channels.
>
> Best,Maité
>
>
> Hi Maité,
>
> Could you please yet let me know how to get the sources timecources?
> source = ft_sourceanalysis(cfg, freq); only gives
> source =
>
>          freq: 18
>     cumtapcnt: [180x1 double]
>           dim: [19 15 15]
>        inside: [4275x1 logical]
>           pos: [4275x3 double]
>        method: 'average'
>           avg: [1x1 struct]
>           cfg: [1x1 struct]
>
> Best,
> Maria
>
> 2017-06-25 13:53 GMT+03:00 Maria Hakonen <maria.hakonen at gmail.com>:
>
>> Hi Maité,
>>
>> Thank you for your answer!
>>
>> I have managed to calculate the coherence between two conditions in the sensor space in the way you suggested. However, I haven't managed to calculate the coherence between conditions in the source space (i.e. Appendix 1 in http://www.fieldtriptoolbox.org/tutorial/coherence). ft_sourceanalysis doesn't have channelcmb. I wonder if anyone has any solutions for this?
>>
>> BTW. I didn't get the answer to my question in my email but found it from Fieldtrip archive. However, I have also got some other emails from fieldtrip discussion forum.
>>
>> Best,
>>
>> Maria
>>
>>
>> Hi Maria,
>> Here it is a possible solution. First, rename channels from one of both conditions: for example, for condition 2, {'ch01cond2', 'ch02cond2', ...}. Then, append the data from both conditions. In ft_freqanalysis introduce all the channels combinations you want:
>>
>> cfg.channel    = {'MEG' 'ch01cond2' 'ch02cond2' ...};
>> cfg.channelcmb = {'ch01' 'ch01cond2'; 'ch02' 'ch02cond2'};
>> As I understand, you could use the same channelcmb later on in ft_connectivityanalysis.
>> I hope it helps.
>> Best wishes,Maité
>>
>>
>>
>> Dear FieldTrip experts,
>>
>> I have just started to use Fieldtrip and would like to estimate coherence
>> between MEG responses measured in two different conditions from the same
>> cortical areas. The example in Appendix 1 is close to what I would like to
>> do:
>> http://www.fieldtriptoolbox.org/tutorial/coherence
>>
>> However, in the example, coherence is calculated between the reference
>> signal (EMG) and all MEG channels. Could it be possible to calculate
>> coherence between each MEG channel in one condition and the same MEG
>> channels in the other condition, that is:
>> ch1 in cond1 vs. ch1 in cond2, ch2 in cond1 vs. ch2 in cond2, ...
>>
>> As far as I understand, the example in Appendix 1 would do this:
>> ch1 in cond1 vs. all channels in cond2, ch2 in cond ch1 all channels in
>> cond2, ...
>>
>> Best,
>> Maria
>>
>>
>
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