Obituary: Michel Jouvet (1925–2017), The father of paradoxical sleep

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Michel Jouvet, who died on October 3, 2017 at the age of 91 can be described as one of the giant of sleep research.
He was born in 1925 in Lons‐le‐Saunier, France. After the Second World War, he was admitted as a resident in neurosurgery in 1951. In 1953, he started neurophysiological research in the department of physiology of the Lyons Medical School. He ‘borrowed’ a 4 channels Alvar EEG machine to record the cortical EEG of cats. Professor Paul Dell, a distinguished neurophysiologist working in Paris taught him how to cut the brain stem of a cat to realize the ‘cerveau isolé’ preparation of Frederic Bremer, the well‐known physiologist from Brussels. He became so interested in experimental neurophysiology that he decided to go in September 1954 for 1 year in Professor Magoun's laboratory in Long Beach (USA). There, he developed a method to record EEG in chronically implanted cats. At the end of 1957, he decided together with François Michel, a young intern to study the mechanisms of habituation of cortical arousal in chronic decorticated cats, in cats with large lesion of the reticular formation, or in mesencephalic or pontine cats. At one point, they decided to record the neck muscle activity (EMG) to obtain some objective motor reaction which could habituate easily in mesencephalic cats. They also implanted electrodes in or very near the oculomotor (VI) nuclei. During 3–6 h EEG recordings, they were surprised to see, every 30–40 min, a periodic appearance of ‘oculomotor‐like’ activity in the pons, which coincided with the total disappearance of the neck EMG. These curious episodes lasted about 6 min and occurred periodically every 50 min. Their discovery demonstrated the existence of a previously undescribed ‘hindbrain (rhombencephalic) sleep’ completely different than slow‐wave sleep (SWS) (Jouvet and Michel, 1959). Very quickly they made complete polygraphic recording in intact cats. They discovered that cortical activity during the new state was similar to that seen during waking but that the threshold for arousal was much increased. This was a paradoxical finding. At this time, W.C. Dement had just published his classical paper on ‘REM sleep’ (Dement, 1958). Michel Jouvet's results clearly indicated that ‘REM sleep’ was a third vigilance state very different from W and SWS. Since PS was present in pontine cats, it could be described as rhombencephalic sleep, whereas slow‐wave sleep could be described as telencephalic sleep Michel Jouvet's results further indicated that ‘dreaming’ was triggered by a structure located in the lower brainstem.
The hypothesis that slow wave sleep depends upon the forebrain and paradoxical sleep depends on the rhombencephalon is still valid today. PS is also found in animals without eyes (as the mole) and in birds which do not move their eyes (as the owl).
In the following years, the laboratory of Michel Jouvet became a world reference for sleep research and he started to delimit the structures responsible for generating paradoxical sleep by local coagulation of the pontine reticular formation. Together with his collaborators, he observed that lesions destroying the dorsolateral part of the pontine tegmentum could abolish selectively paradoxical sleep (PS) without altering SWS. They further showed that smaller lesions of this area induced a state of PS without muscle atonia (Jouvet, 1962). Later, in 1979, he described with Jean‐Pierre Sastre, the oniric behaviours expressed by cats, indicating that cats also dream. In 1986, REM sleep behaviour disorder was discovered in Humans and it was proposed that these patients might have a lesion of the pontine generator of atonia discovered by Michel Jouvet.
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