RESUMO
AIM To compare the new methods which can be used fo r soring the stages of rat sleep. METHODS Cortical EEG and hippocampal potential(HP) were collected by implanted electrodes in freely moving rats. Gravity frequency (f g) and the complexities(Kc,C 1), were calculated. According to the characteristics of each stage and by studying the histogram of f g, Kc and C 1, the stages of rat sleep were distinguished. RESULTS The methods of f g, Kc and C 1 can distinguish the Waking, nonrapid eye movement(NREM) and REM sleep well. Comparing the results of visual and our analysis, the rate of accordance is above 85%, and the analysis based on the complexity measure is more believable than that based on the f g. CONCLUSION The gravity frequency and the complexities of Kc,C 1 can be used to distinguish the different stages of rat sleep.