[Eeglablist] What is the unit of datas in EEG.data

[GROSSELIN, Fanny]

Hi,

Thank you for your response. My data format come from Brain Vision so I
don't use loadvg(). I use pop_loadbv and this function save units because
it is written :
for chan = 1:length(chans)
        [EEG.chanlocs(chan).labels, chanlocs(chan).ref,
chanlocs(chan).scale,* chanlocs(chan).unit*] =
strread(hdr.channelinfos{chans(chan)}, '%s%s%s%s', 1, 'delimiter', ',');

However, it doesn't appear in the workspace of Matlab... chanlocs.unit is
undefined.

Best,

Fanny


2014-04-25 6:05 GMT+02:00 Stephen Politzer-Ahles <spa268 at nyu.edu>:

> I think there is one exception, which is that the loadavg() function for
> Neuroscan .avg data does some kind of scaling (see see
> http://sccn.ucsd.edu/pipermail/eeglablist/2011/003986.html and some other
> messages on the list) so the data aren't in microvolts or (I think) a
> straightforward multiple of microvolts. I'm not sure if that's your data
> format, but if it is then that message includes a different function you
> can use to get the data in microvolts.
>
> Best,
> Steve
>
>
>
> Stephen Politzer-Ahles
> New York University, Abu Dhabi
> Neuroscience of Language Lab
> http://www.nyu.edu/projects/politzer-ahles/
>
>
> On Fri, Apr 25, 2014 at 7:19 AM, Makoto Miyakoshi <mmiyakoshi at ucsd.edu>wrote:
>
>> Dear Fanny,
>>
>> That's an interesting question. I guess the unit is fixed to be
>> microvolt, and it's not written anywhere!
>>
>> Makoto
>>
>>
>> 2014-04-24 0:57 GMT-07:00 GROSSELIN, Fanny <fanny.grosselin at edu.esiee.fr>
>> :
>>
>>> Hi Makoto,
>>>
>>> Thank you for your response. However, I wonder if unit is saved
>>> somewhere in the workspace of Matlab or if I have to get back it in the
>>> header file?
>>>
>>> Fanny
>>>
>>>
>>> 2014-04-23 22:40 GMT+02:00 Makoto Miyakoshi <mmiyakoshi at ucsd.edu>:
>>>
>>> Dear Fanny,
>>>>
>>>> I know some of import function can specify the units for amplitudes. If
>>>> you have problem, you can try
>>>> EEG.data = EEG.data*/1000;
>>>> to convert microvolt to millivolt.
>>>>
>>>> Makoto
>>>>
>>>>
>>>> 2014-04-23 8:13 GMT-07:00 GROSSELIN, Fanny <
>>>> fanny.grosselin at edu.esiee.fr>:
>>>>
>>>>> Hi everybody,
>>>>>
>>>>> I would like to know what the unit of data is in EEG.data?
>>>>> Is there microvolts unit for any type of file loaded, even if data are
>>>>> in millivolts in the initial file?
>>>>>
>>>>> Thank you in advance for your help,
>>>>>
>>>>> Fanny
>>>>>
>>>>> _______________________________________________
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>>>>
>>>>
>>>>
>>>> --
>>>> Makoto Miyakoshi
>>>> Swartz Center for Computational Neuroscience
>>>> Institute for Neural Computation, University of California San Diego
>>>>
>>>
>>>
>>
>>
>> --
>> Makoto Miyakoshi
>> Swartz Center for Computational Neuroscience
>> Institute for Neural Computation, University of California San Diego
>>
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