What does this channel measure?
This channel measures muscular activity of specific facial muscles
(e.g. m. corrugator or zygomaticus) or general tension related muscles
(e.g. neck). High activity of the muscle is reflected in rapidly
oscillating signals of large amplitudes. The raw signal is
highpass-filtered at 28 Hz, rectified, and smoothed with a 16 Hz lowpass
filter or moving average.
The oscillating signal thus becomes a smoother curve with only positive
values, that can directly be interpreted in terms of amount of muscle
activity.
To change filter settings, you can edit the 'anslabdef.m'-file in your
study folder and manually change the filter values. Alternatively you
may change the respective values through the ANSLAB options dialog.
They are read in before loading data and will be applied to the loaded data.
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Editing of EMG Data
This signal hardly requires any editing. Moreover, artifacts are
difficult to separate from normal activity. You can however exlude
outliers if you are sure about artifactual epochs and set them to
missing values.
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