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Extracting data epochs

Data epochs are extracted from the filtered, transposed data based on a timing file, which is created when opening the raw data file. You can manually this textfile before running the epoch extraction to exclude specific trial from the extraction.

After you push the "Resume analsis"-button, you can select a number of data points to extract before (Pretrigger) and after (Posttrigger) the onset of each event listed in your timing file (dialog shown below). Only the "Start" column in the timing file is used, the "End" column is ignored.

You can extract only a subset of conditiong by activating the "Use only"-radiobutton and entering condition numbers to extract in the adjacent text field.

You can select to ignore specific events (for instance calibration trials for the RAAA procedure) by activating the "Use all events but ignore"-radiobutton and entering condition numbers in the adjacent text field.

You can subdivide trials of each condition in equally sized parts by activating the "Subdivide events in N parts"-checkbox and selecting the number of subdivision on the adjacent spinbox. Conditions will be numbered by appending part numbers to the condition name, e.g. condition 4 subdivided in 3 parts will result in the conditions 41, 42, and 43.

After pressing OK, EMEGS extracts the data epochs, saves them to diskfile, and displays first extracted epoch. This should look something similar to this:

In your data folder, you can the epoch file (*.SES) and an additional condition file (*.CON), which is a reduced timing file, containing only the condition number for every data epoch.