[FieldTrip] Analyzing SSVEPs

[Eelke Spaak]

Hi Sarah,

If, as you say, the .mat files indeed contain data already
preprocessed with FieldTrip, then a simple "load <matfile>" should
work? (So using Matlab's own "load", rather than any FieldTrip reading
function.) If it doesn't work, then we'll need a bit more information
on what exactly is going wrong (error messages, exact script code,
etc.).

Best,
Eelke

On Fri, 1 May 2020 at 11:48, Sarah Kirchler <sarah.kirchler at gmail.com> wrote:
>
> Hi Eelke,
>
> thank you for your answer!
> I think you understood pretty much right, thank you also for the link to the website.
> The problem is, that I have data saved as .mat-files but already preprocessed with Fieldtrip.
> Now I want to use this data to do my SSVEP analysis, but if I try to load the .mat-file, I get error messages. I also get the error message, that the functions of the example script in Fieldtrip just work for ft_datatype_raw, that "contains sensor level time domain data typically obtained after calling ft_definetrial and ft_preprocessing." So it should work for my datastructure, but it doesn't. Maybe I make a bad mistake and should load the original vhdr-file and the mat-file together, I'm not sure, but in my comprehension all the data that I need should be in the preprocessed .mat-file.
> Please correct me if I do wrong, I'm a beginner willing to not give up!
>
> Thank you very much in advance,
>
> Sarah
>
> Am Do., 30. Apr. 2020 um 13:52 Uhr schrieb Eelke Spaak <e.spaak at donders.ru.nl>:
>>
>> Hi Sarah,
>>
>> If I'm not mistaken, your question is essentially: I already have data
>> in Matlab arrays, how can I make sure FieldTrip understands this? (So
>> the question is independent of SSVEP or any specific analysis
>> pipeline.) Have a look at
>> http://www.fieldtriptoolbox.org/faq/how_are_the_various_data_structures_defined/
>> and specifically ft_datatype_raw for pointers.
>>
>> Best,
>> Eelke
>>
>> On Thu, 30 Apr 2020 at 12:05, Sarah Kirchler <sarah.kirchler at gmail.com> wrote:
>> >
>> > Hi Fieldtrip!
>> >
>> > I have a question About analyzing SSVEPs.
>> > I don’t really know how to make a Connection from Fieldrtrip to my already preprocessed data. I have a Folder named „clean“, where I have saved the data rejected from artifacts.
>> >
>> > You offer only an example script „How to analyze SSVEPs with simulated data“, but I have real data and don’t know how to read it in.
>> >
>> > The function ft_read_data doesn’t support .mat-files, in which I saved my clean data.
>> >
>> > How can I create a dataset out of my clean data? Or how can I read in the clean data with the .mat-endings?
>> >
>> > Thanks for your answers!
>> > And excuse my incorrect english.
>> >
>> > Best,
>> >
>> > Sarah Kirchler
>> >
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>> > https://doi.org/10.1371/journal.pcbi.1002202
>>
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