Negative value for Theta and Alpha when (averaged)

I collected EEG data and wanted to work on Theta band power with Af7 and Af8 channels but I am getting negative average value for Theta band corresponding to a certain task. Is there something wrong? There should not be a negative value for power.

Please help me understand the reason behind negative average values for Theta and Alpha bands.


the Muse SDK automatically takes the log10() of the power, so anything that was originally less than 1 will give you a negative. Not sure why they do that, I always do 10^power to get it back to the original value before doing anything with it.

@slmille4, Original value is the results in Frequency?

No, it’s the original band power, which can then be re-normalized according to some baseline