Thalamic control of eeg oscillations during waking, NREM and REM sleep

The thalamus is the regulator not only of the sleep-wake cycle, but also of the rhythmic oscillations of electroencephalographic synchronized waves. In this contribution I first wish to discuss current views about EEG synchronized rhythms, particularly the synchronized EEG spindle waves, and their thalamic origin. Spindle waves are high-amplitude oscillations in the frequency range of 6-14 Hz associated with the early stages of sleep. In the second part of this paper, I summarize experimental findings obtained using lesioning techniques of discrete thalamic nuclei (medialis dorsalis, intralaminar complex, nucleus reticularis), supporting different roles of different thalamic cell populations on the regulation of sleep and of physiological correlates of synchronized and desynchronized states, particularly the EEG oscillations.