[Eeglablist] ERSP in STUDY

Baris Demiral demiral.007 at googlemail.com
Tue Feb 2 14:04:37 PST 2010


Hi Isabel,

I do not have a direct answer to your question, but as someone trying to
learn the pros and cons of the ersp analysis from study files, I find your
point very important. You mentioned in your message that you merged the data
of 8 subjects per condition and then did channel time-frequency analysis.
This means that you formed data sets of aggregate ERP amplitude-times for
each condition, and compared the two samples. So, in this case, you did a
t-test (is it Arno?) This may have led to a Type 2 error, showing you the
significant things as non-significant. Actually, my question at this point
is: in ERSP stats (parametric) in eeglab do we do Anova having subjects as
random factors?

Best,
Baris

On Tue, Feb 2, 2010 at 8:19 AM, <isacor at us.es> wrote:

> Hello everyone.
> I created a study with 8 subjects and three conditions.The sampling
> frequency is 1024. The time window ranging from -1800 ms to 500 ms. To
> compute the ERSP have used the following parameters:
> 'cycles', [1.5 0.5], 'nfreqs', 100, 'baseline', [-1500 -1400], 'padratio',
> 4, 'alpha', 0.01
> When I visualize ERSP activity for a certain channel, I hope that no
> significant activity was plotted in green. However this does not happen, or
> not take into account the level of significance.
> Do not know if I used the appropriate parameters. When I do a merged with
> my 8 subjects for a condition and I use the same parameters from eeglab
> through 'channel time-frequency' , non-significant features are plotted in
> green.
> In the study to the time of making the channels precompute've left anything
> out?
> I hope your help.
> Thank you.
>
> Isabel Cordones Cano
> Neurociencia y Comportamiento
> Fisiología Animal Y Zoologia
> Facultad de Biología, Universidad de Sevilla
> Avda. Reina Mercedes 6, 41012-Sevilla
> España
>
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-- 
SB Demiral, PhD.
Department of Psychology
7 George Square
The University of Edinburgh
Edinburgh, EH8 9JZ
UK
Phone: +44 (0131) 6503063
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