Relative power contributions of unit discharges simultaneously recorded in the mesencephalic reticular formation

In order to investigate mutual interactions between neuronal discharges in the mesencepahlic reticular formation, relative power contributions (RPC) were estimated during sleep-wake cycles and serotonin (5HT)-depleted conditions by the administration of parachlorophenylalanine (PCPA). The RPC for most of the neurons dominated in the lower frequency range below 0.4 Hz during rapid eye movement (REM) sleep and the PCPA-treated conditions, which were qualitatively reproduced by the neural network model under global disinhibition. The results supported the hypothesis that the peculiar dynamics of neuronal activities during REM sleep, 1/f fluctuations, were generated by neuronal interactions augmented by the release from the global inhibition of 5HT.