[FieldTrip] Fwd: Using Akaike Information Criterion for order selection with ft_mvaranalysis

[Nitzan Uziely]

Hi,

My name is Nitzan Uziely, and I'm a student (under-grad) at the Hebrew
University of Jerusalem.

I'm using fieldtrip to process EEG signals at our lab, and I'm trying to
run a PDC analysis on my data.

I took the data, calculated the inverse-solution and segmented it into
virtual channels using the AAL atlas.

I'm trying to to calculate the correct order for the ft_mvaranalysis
function.
I've seen a previous question that went unanswered a few years ago about
order selection (
http://mailman.science.ru.nl/pipermail/fieldtrip/2011-June/003947.html).

Following the above question, I searched how to calculate the Akaike
Information Criterion (AIC) to calculate the correct model order. According
to http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2585694/ I need to calculate
the determinant of the noise covariance matrix, however the determinant
(I've checked orders 1 to 10) is so small that matlab just rounds it to
zero. This makes me feel that either I have a problem, I've misunderstood
how to calculate AIC to select the correct model, or that AIC is not the
correct way to go.

So, my question is - does it seem that is something wrong with my data
(which can be seen by the small determinant), am I misunderstanding the
requirement of the determinant or is there a better way to select the order
of the mvar model. (oh, I'm using mdcfg.toolbox = 'bsmart'; if it matters)

Thanks,

Nitzan.
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