# [Eeglablist] plot of components spectra and maps

ida miokovic ida.miokovic at gmail.com
Sat Jun 9 07:56:17 PDT 2012

```I just came to conclusion that these frequencies are rounded to the nearest
value (0Hz, 0.5Hz, 1Hz) when plotting, am I right?

Are they rounded in calculations also or a specified value is used? Is
there a way for me to work with the actual frequency I want? How could I
call this function as a code? I tried following:

pop_spectopo('EEG',[-2000 1000],100,0.33)

for current EEG data set, specified range, 100% of the data and 0.33 Hz as
a frequency of interest, but something is not OK and I get following error:

??? Attempt to reference field of non-structure array.

Error in ==> pop_spectopo at 120
if ~isempty(EEG.chanlocs)

Thank you very much for any help.

Ida

On Sat, Jun 9, 2012 at 3:15 PM, ida miokovic <ida.miokovic at gmail.com> wrote:

> Hello,
>
> I have question regarding procedure: Plot --> Components spectra and maps.
> I am interested in channel with the maximum power at the specified
> frequency so I put brackets [] in the electrode number to analyze and I use
> 100% of the data.
>
> Frequency of my interest is for example 0.27 Hz, but when the calculation
> is done, on the plot I get the scalps (components activities) connected to
> the frequency around 0.45 Hz (plotting frequency range was 0 1). Same
> happens for the frequency 0.25 Hz (on the plot I get 0.45 Hz). On the other
> side, plot of the 1Hz is OK. In the workspace it is using value I put in
> the GUI, but on  the plot in case of 0.25, 0.27, 0.3, the frequencies are
> not those from the GUI.
>
> To me, it is important to get the channel of my interest and the
> components where there is the most of specified frequencies. If it is just
> plotting issue, I don't mind, but any hints why does it happen would be
> great. Maybe it is working better with integer values of frequencies...
>
> Thanks
>
> Ida
>
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