In-phase brain activities during arousal and sleep.
EEG of sensorimotor area, EMG of neck muscles and unit activity in lateral geniculate (LG) nucleus, recorded in freely moving cats, were analysed for the presence of correlations between them. The 3 activities were first integrated with a 2 sec time constant, then a correlation coefficient was assessed between time-linked points of the 3 records for periods of 40 sec. The average vlaues of the correlation coefficients were found to increase from arousal through slow synchronized sleep (S sleep), reaching the highest value in REM sleep. The average of the values in REM was found to be significantly different from those in arousal and S sleep. These differences were statistically significant for the correlation coefficients between EEG and LG activities, as well as of EMG and LG. On the contrary, the correlation between EEG and EMG, which may be thought of as having more direct anatomical connections and a higher degree of physiological dependence, did not change as a function of the different physiological states.
D000818:Animals; D001143:Arousal / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D002415:Cats; D004569:Electroencephalography; D004576:Electromyography; D012890:Sleep / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology