COCAINE-INDUCED INCREASES IN EEG-ALPHA AND EEG-BETA ACTIVITY - EVIDENCE FOR REDUCED CORTICAL PROCESSING

To understand the effects of cocaine on the cerebral cortex, 14 male p olydrug abusers were enrolled in a study on the effects of cocaine on the electroencephalogram (EEG). The experimental treatments were place bo, 20 mg cocaine or 40 mg cocaine IV administered in a double-blind, pseudorandom design. The EEG was recorded from 13 electrode positions over the left hemisphere during a 3-minute baseline recording and for 30 minutes after initiation of the IV injection. The spectral power fo r delta, theta, alpha and beta EEG bands was calculated from data coll ected in each 3-minute interval. Cocaine significantly increased beta in frontal and central areas and enhanced alpha in frontal and tempora l regions. Cocaine-induced increases in EEG beta power had a cortical distribution similar to those produced try barbiturates and benzodiaze pines. As all of these drugs reduce cortical glucose metabolism, the i ncreases in beta power may reflect a reduction in cortical neural acti vity.