Hi,
We preprocessed all EEG files using EEGLab then, try to run averaged file (.erp) in ERP PCA toolkit to separate certain ERP component from other components then, will pull out "pure" ERP component values from certain TF factor.
To start this, I am trying to load grand-averaged erp files across all subjects (.erp) (see the attached). In "read" function, when I loaded the file, it says, ' defective file will not be loaded'. Would you please check the attached file?
Q1. can I use grandaveraged file to run PCA and then, still pull out each individual's certain ERP values from TF factors?
Q2. or should I load each subject's averaged .erp file? I tried out this way but, couldn't create one file including all subjects' files so couldn't run temporal PCA in next step.
Thanks for your help!!
Hi, I've fixed the bug. It was due to a change in how grand average data are represented in the EP Toolkit and will send you the fix. As for the questions, you cannot pull out the individual subjects after having used a grand average file. That would be equivalent to your telling me that the mean reaction time of a dataset is 500 ms and then asking me to pull out the individual reaction times from that one single number. In any case, my 2010 paper showed you don't get as good results from a grand average. Use the Single File mode to read in separate subject averages. See the tutorial for how this all works.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi,
We preprocessed all EEG files using EEGLab then, try to run averaged file (.erp) in ERP PCA toolkit to separate certain ERP component from other components then, will pull out "pure" ERP component values from certain TF factor.
To start this, I am trying to load grand-averaged erp files across all subjects (.erp) (see the attached). In "read" function, when I loaded the file, it says, ' defective file will not be loaded'. Would you please check the attached file?
Q1. can I use grandaveraged file to run PCA and then, still pull out each individual's certain ERP values from TF factors?
Q2. or should I load each subject's averaged .erp file? I tried out this way but, couldn't create one file including all subjects' files so couldn't run temporal PCA in next step.
Thanks for your help!!
-Yu Sun
Hi, I've fixed the bug. It was due to a change in how grand average data are represented in the EP Toolkit and will send you the fix. As for the questions, you cannot pull out the individual subjects after having used a grand average file. That would be equivalent to your telling me that the mean reaction time of a dataset is 500 ms and then asking me to pull out the individual reaction times from that one single number. In any case, my 2010 paper showed you don't get as good results from a grand average. Use the Single File mode to read in separate subject averages. See the tutorial for how this all works.