French re­searcher un­locked se­crets of REM sleep

Honolulu Star-Advertiser - - IN MEMORY - By Daniel E. Slotnik

Dr. Michel Jou­vet, a neu­ro­phys­i­ol­o­gist who dis­cov­ered the re­gion of the brain that con­trols rapid eye move­ment, and who helped de­fine REM sleep as a unique state of con­scious­ness com­mon to hu­mans and an­i­mals alike, was found dead on Oct. 3 in Villeur­banne, France. He was 91.

Pierre-Hervé Luppi, a fel­low re­searcher who worked with Jou­vet for many years, said he had died overnight at a hos­pi­tal.

The cu­ri­ous phys­i­o­log­i­cal phe­nom­e­non known as REM sleep was first re­ported in the early 1950s by Eu­gene Aserin­sky and Nathaniel Kleit­man, re­searchers at the Univer­sity of Chicago. They no­ticed that peo­ple who ap­peared to be sleep­ing soundly some­times moved their fully lid­ded eyes, and that elec­troen­cephalo­gram record­ings showed that brain ac­tiv­ity dur­ing pe­ri­ods of eye move­ment was closer to that of some­one awake than some­one un­con­scious.

They and an­other col­league, Wil­liam C. De­ment, even­tu­ally de­ter­mined that sleep­ers had in­ter­mit­tent pe­ri­ods of REM dur­ing which they of­ten dreamed.

JOU­VET WAS a re­searcher at the Univer­sity of Lyon in France, study­ing how sleep­ing cats re­act to stim­uli, be­fore he turned his at­ten­tion to REM in the late 1950s.

In deep, or slow-wave, sleep, both cats and hu­mans show slight mus­cle ten­sion and low brain ac­tiv­ity. But Jou­vet found that dur­ing pe­ri­ods of REM sleep the mus­cles of cats were com­pletely slack, even though their brain waves sug­gested phys­i­cal ac­tiv­ity. He called the REM state “para­dox­i­cal sleep,” since the brain is ac­tive even though the body is vir­tu­ally still.

“Dream­ing be­came the third state of the brain, as dif­fer­ent from sleep as sleep was from wak­ing,” Jou­vet wrote in “The Para­dox of Sleep: The Story of Dream­ing,” pub­lished in France in 1993 and in English six years later.

He de­ter­mined that a struc­ture within the brain­stem called the pons gov­erned cats’ REM sleep. The pons is re­spon­si­ble for ba­sic bi­o­log­i­cal func­tions, like breath­ing and sen­sory per­cep­tion; by con­trast, the cor­tex, a higher brain re­gion, gov­erns con­scious thought and ac­tions.

Many re­searchers at the time as­sumed that since dream­ing seemed to be a com­plex in­tel­lec­tual process, it would be cen­tral­ized in the part of the brain re­spon­si­ble for rea­son­ing. Jou­vet’s dis­cov­ery sug­gested that REM sleep could con­tinue with­out the in­volve­ment of higher brain struc­tures and that it had an im­por­tant bi­o­log­i­cal func­tion even for an­i­mals with lit­tle ca­pac­ity for rea­son­ing.

Re­search has since con­firmed that hu­man be­ings have brain struc­tures that gov­ern REM sleep sim­i­lar to those found in cats. Most warm-blooded an­i­mals, like mam­mals and birds, have pe­ri­ods of REM sleep. (Many species of whales are no­table ex­cep­tions.)

Jou­vet also con­ducted early re­search on Modafinil, a stim­u­lant used to suc­cess­fully treat nar­colepsy and other sleep dis­or­ders. Modafinil, in­tended to pro­mote wake­ful­ness with a lower risk of ad­dic­tion than am­phet­a­mines, has be­come pop­u­lar as a so-called smart drug.

COUR­TESY PHOTO

Michel Jou­vet ———

Newspapers in English

Newspapers from USA

© PressReader. All rights reserved.