[Eeglablist] Observation of only high spectral power in lower frerquencies

[sandeep b]

Hi,

I'm working on matlab to study different classification algorithms for SMR
(sensorimotor). I record about 13 to 16  seconds of data (over 60 trials -
30 left and 30 right, 10 different people), and deleted background (by
subtracting mean of each channel). Then I applied a simple FFT, but when i
plot it i see that there is high spectral power in low frequencies (0 up to
4 - 5 HZ). Why there is this high spectral power in lower frequencies.?
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