# [Eeglablist] Maximum segment average amplitude, from single epochs

Makoto Miyakoshi mmiyakoshi at ucsd.edu
Mon Mar 24 18:12:42 PDT 2014

```Dear Gaspar,

Without checking it with Matlab...
To make it simple, I'll use millisecond instead of datapoints.

channelOfInterest = 10; % let's say you want to see Ch10.
maxPoint = squeeze(max(EEG.data(channelOfInterest,300:800,:),[],2));
minPoint = squeeze(max(EEG.data(channelOfInterest,maxPoint:1300,:),[],2));
% Does this work? If not (and probably not), use for simple for loop, like

minPoint = zeros(1,length(maxPoint));
for n = 1:length(maxPoint)
minPoint(n) =
squeeze(max(EEG.data(channelOfInterest,maxPoint(n):1300,:),[],2));
end

meanMaxValue =
squeeze(mean(EEG.data(channelOfInterest,maxPoint-50:maxPoint+50,:),2));
meanMinValue =
squeeze(mean(EEG.data(channelOfInterest,maxPoint-50:minPoint+50,:),2));

Let me know if this does not work.

Makoto

2014-03-24 10:21 GMT-07:00 Bastien Boutonnet <bastien.b1 at gmail.com>:

> Do you basically want to collect the maxima and then average over those
> maximums?
>
> -
> Bastien Boutonnet, Ph. D.
> Department of Psychology
> University of Wisconsin, Madison
> bastienboutonnet.com
>
>
> On 24 March 2014 05:44, Gaspar Lukacs <lkcsgaspar at gmail.com> wrote:
>
>> Hi all,
>>
>> I have problems with data extraction from single epochs, for which I'll
>> probably need an algorithm. Specifically, within each epoch, from 300 to
>> 800 ms I need to get the maximum positive 100 ms segment average amplitude,
>> and then from the midpoint of this segment to 1300 ms, the maximum negative
>> 100 ms segment average.
>>
>> The closest thing I could find is a "meanepoch.m" script which gets mean
>> values between given latencies from single epochs - but it cannot search
>> for maximum mean values (i.e. segment  averages)..
>>
>> I would be very grateful for any suggestions.
>>
>> Regards,
>> Gaspar
>>
>> /Institute of Psychology, University of Szeged/
>>
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--
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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