Hello,
I have used the Cluster function for Power to generate the global field power of 59 EEG electrodes, but when I view the results (image below), there is no unit, only scale. Is the base unit µV or V, or something else?
Hello,
I have used the Cluster function for Power to generate the global field power of 59 EEG electrodes, but when I view the results (image below), there is no unit, only scale. Is the base unit µV or V, or something else?
Hi @RenataKoch,
The units for the Power cluster function will be [V²]
for EEG, and [T²] for MEG.
Being x
of the shape [nSensors, nSamples]
, the Power function returns the average across sensors of the square of the all the signals: mean(x.^2, 1)
GFP is computed as the standard deviation across sensors: std(x, 1, 1)
The results between power function and GFS are very similar or event identical as the mean of all the sensor values at a given time point is zero most of the time. If average reference is used, power and GFP are the same.