The FFT mathematical conversion applied to EEG signals takes into account both frequency and amplitude of the signal within defined powers (frequency bands). The frequency analysis revealed differences between a particular class of drugs allowing “fingerprinting” of hallucinogenic and non-hallucinogenic amphetamine derivatives. While an increase in alpha1 power correlating with a serotonin increase were observed in hallucinogenic actions, the spectral patterns following exposure to non-hallucinogens were characterized by a decrease in the alpha2 and delta band [2].
