[FieldTrip] read_biosig_header.m

"Jörn M. Horschig" jm.horschig at donders.ru.nl
Wed Jul 11 10:20:58 CEST 2012

Dear Steve,

Although I cannot help you directly and do not know about the specific 
error you got, you can find all code changes on 

For the biosig file you are referring to, please look here:
(but as you can see, nothing changed there)

Hope someone else can help out (Robert is on vacation right now, so 
maybe someone else can help)


On 7/10/2012 8:49 PM, Steve Deiss wrote:
> The fieldtrip version we have calls function 'read_biosig_header' 
> which calls 'sopen' with the following sequence.
>      biosig = sopen(filename,'r');
> For some reason it loses the digital triggers on channel 1 in our data 
> after issuing the following warning:
> "Reading data file header...
> WARNING SOPEN(EDF): Physical Max/Min values of EDF data are not 
> necessarily defining the dynamic range.
>    Hence, OVERFLOWDETECTION might not work correctly. See also 
> EEG2HIST and read
>    http://dx.doi.org/10.1016/S1388-2457(99)00172-8 (A. Schlgl et al. 
> Quality Control ... Clin. Neurophysiol. 1999, Dec; 110(12): 2165 - 2170).
>    A copy is available here, too: 
> http://www.dpmi.tugraz.at/schloegl/publications/neurophys1999_2165.pdf "
> If we let EEGLAB read the data, its function 'pop_biosig' calls 
> 'sopen' with
>      biosig = sopen(filename,'r',0,'OVERFLOWDETECTION:OFF');
> The data read in here includes the triggers so that we can go on to 
> epoch and process the data.
> We are not yet ready to upgrade to the very latest fieldtrip.  So I 
> would like to know if there is an easy way to
> determine if the latest version of fieldtrip changed anything in the 
> way sopen is called from read_biosig_header?
> If it matches what EEGLAB does here, we can match that as a temporary 
> fix.
> I'll try to download and unpack it to see, but if this is a known 
> problem, fixed or not, I'd appreciate any tips.
> Thanks
> Steve
> _______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip

Jörn M. Horschig
PhD Student
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognitive Neuroimaging
Radboud University Nijmegen
Neuronal Oscillations Group

P.O. Box 9101
NL-6500 HB Nijmegen
The Netherlands

E-Mail: jm.horschig at donders.ru.nl
Tel:    +31-(0)24-36-68493
Web: http://www.ru.nl/donders

Visiting address:
Trigon, room 2.30
Kapittelweg 29
NL-6525 EN Nijmegen
The Netherlands

More information about the fieldtrip mailing list