[Eeglablist] Window of integration

[Darren Weber]

Tom Campbell, Ph.D. wrote:

> Hi,
> 
> As something of a newcomer doing rather standard ERP analyses for the time 
> being, one thing that I am interested in doing is computing the average 
> amplitude in a window of integration in a given time range (e.g. 62.5-67.5 
> ms post onset) that is centered on a given group averaged peak (e.g. at 65 
> ms at Cz). 
> 
> This sort of thing is/was available in Neuroscan 3.x STATS using AREA ON 
> and a template. I figure it did something like a high sampled spline fit 
> in a given the template time range for each electrode, a spot of integral 
> calculus to calculate the area under this curve and then divided by the 
> duration of the template range on the time axis. (Please, suggestions for 
> a book on this would be appreciated).

You could try generating a time series with 'linspace' to get the temporal 
resolution required, then using that timeseries in the 'interp1' function with 
the spline option for interpolation.  That might get you the kind of 
interpolation your looking for.


> 
> Please may ask if there are functions to do this method for calculating 
> amplitudes in a given range in EEGLAB?
> 
> Alternatively, please is there a simple way to access the data structures 
> that store the ERPs used by pop_plotdata()? 
> 
> Suggestions welcome.


Best, Darren

-- 

Darren L. Weber, Ph.D.
Postdoctoral Research Fellow

Dynamic Neuroimaging Laboratory, Department of Radiology,
University of California, San Francisco,
185 Berry Street, Suite 350, Box 0946,
San Francisco, CA 94107, USA.

Tel: +1 415 353-9444
Fax: +1 415 353-9421
www: http://dnl.ucsf.edu/users/dweber

"To explicate the uses of the brain seems as difficult
a task as to paint the soul, of which it is commonly
said, that it understands all things but itself."
--Thomas Willis (The Anatomy of the Brain and Nerves, 1664)