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

[Makoto Miyakoshi]

Dear Arno,

I've never thought of it, but could it be anything other than microvolt?

Makoto


2014-04-25 0:14 GMT-07:00 GROSSELIN, Fanny <fanny.grosselin at edu.esiee.fr>:

> 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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>>
>>
>


-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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