Importing the data

Before you can go into the analysis of your data, you have to import all the EEG/ERP data and specify the design of the experiment. Make sure you have all your EEG/ERP data organized as follows:

Ragu data import dialog

 When you have successfully imported the ERP data, you are directly taken to the dialogs that specify the remaining parameters of the data, i.e. your montage, and the sampling parameters.

Defining the montage

If you're not automatically arriving here, this procedure can be reached under Data->Montage. Here, you can (optionally) define the montage of your data, which will later allow you to better visualize the results. When you work with Analyzer and Matlab, you can simply save the Channel structure to a Matlab file and load this file as your montage. This is the procedure:

Alternatively, you can load a text file with the xyz coordinates of the electrodes. (x<0 is left x > 0 is right, y>0 is anterior, y < 0 is posterior), z > 0 is superior, coordinates should be on a sphere with radius 1 or use one of the standard sLORETA or CarTool electrode coordinate files. A sample file for download and editing is available here.

 Defining the sampling interval and latency of the first sample

Use the Data->Data Properties menu item to specify the sampling interval (time / frequency interval between adjacent points on the x-axis), sampling units and the X onset to get proper axes in your displays. Onset is defined as the latency of the first time-point of your data in reference to zero on the x-axis. Thus, if you have a 100ms pre-stimulus period, set the time onset to -100.

Category: Ragu manual
Hits: 13055