Continuous correlation between brain activities.
In free-behaving cats, bearing chronically implanted electrodes, the cross-correlation coefficients between EEG, EMG and unit activity in the Lateral Geniculate nucleus (LGU) have been computed continuously at 1 sec interval for epochs of several minutes, in the three basic physiological states: slow wave synchronized sleep (S-sleep), REM-sleep and Arousal. The coefficients exhibit continuous and aperiodic oscillations between high positive and high negative values. The means of the coefficients for each pair of variables exhibit significant differences between the three states. The phase times also are varying significantly for each variable pair in different states. During the transition from one state to another the coefficients follow characteristic time patterns. In the stationary phase of the different physiological states the correlation coefficients follow similar waxing and waning patterns. Embedded in the steady waxing and wanings of the coefficients are frequently found r time patterns similar to those of a state transition: the incomplete and sham transitions. All the results support the hypothesis that the diffuse projecting systems are inducing a continuous pressure to change the state of the brain activity, which is revealed by the changing of the correlations between the different brain structures.
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D002415:Cats; D004569:Electroencephalography; D004576:Electromyography; D005829:Geniculate Bodies / Q000502:physiology; D012890:Sleep / Q000502:physiology; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology