Electroencephalography (EEG) is a method for measuring the
electrical activity in the brain by placing electrodes on the scalp.
Typically, the signal measured is made up of different types of brain
activity which are characterised by their frequency.
- Delta <4Hz
- Theta 4-7Hz
- Alpha 8-15Hz
- Beta 16-31Hz
- Gamma >32Hz
The
data collected in LabChart can be filtered using a digital bandpass
filter to show each of the specific frequency bands. This is acheived by
going to the channel drop down menu, choosing Digital filter....
In
the dialog, the source channel should be the raw EEG channel, the
filter chosen should be bandpass and the the upper an lower Fq limit can
be set for the specific bandwidth (eg Alpha would be set at 15Hz and
8Hz)
This can be repeated for each bandwidth that you wish to display, each on a separate channel.
NB. Depending on electrode placement, some brain waves may be more or less prominent in certain regions of the brain.
