[Eeglablist] Global field power calculations

[Stephen Politzer-Ahles]

Hi Mridula,

You can export .avg files directly into EEGLAB using the attached function
(not my own creation--this is a function that Dr. Yang Zhang kindly shared
with me). The syntax is like:

[signal, variance, chan_names, pnts, rate, xmin, xmax] =
loadavg_bcl('some_neuroscan_file.avg');

(Note: EEGLAB also comes with a built-in function, loadavg(), that works in
the same way. However, last time I checked, this function rescales the
data, so the data that you have in MATLAB after import are not in
microvolts but in some other units. If you want to work with data in
microvolts, you can use the attached function.)

Once the data are in MATLAB, calculating global field power (both
for individuals and across multiple individuals) is just arithmetic and can
be done with some simple MATLAB scripting, it shouldn't need EEGLAB.

Best,
Steve



On Mon, Jun 25, 2012 at 9:53 AM, Mridula Sharma <mridula.sharma at mq.edu.au>wrote:

> Hi,
>
> We have data recorded from NeuroScan with 32 channels comparing 3
> conditions within normal population. We would like to calculate and
> statistically compare the GFP for the 3 conditions.
>
> So can we export the .avg file to EEGlab and calculate and can this be
> done in individuals and across group.
>
> thanks
> Mridula
>
> --
> Mridula Sharma, PhD
> Senior Lecturer and Program Convener
> Department of Linguistics
> Faculty of Human Sciences
> Room C5A 518
> Macquarie University
> NSW 2109 Australia
>
> Tel: +61 2 9850 4863
> Email: mridula.sharma at mq.edu.au
>
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-- 
Stephen Politzer-Ahles
University of Kansas
Linguistics Department
http://www.linguistics.ku.edu/
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