Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!netnews.upenn.edu!pender.ee.upenn.edu!rowe From: rowe@pender.ee.upenn.edu (Mickey Rowe) Newsgroups: sci.bio Subject: Re: Echidnas & REM sleep Message-ID: <42333@netnews.upenn.edu> Date: 1 May 91 00:49:31 GMT References: Sender: news@netnews.upenn.edu Reply-To: rowe@pender.ee.upenn.edu (Mickey Rowe) Organization: University of Pennsylvania Lines: 67 Nntp-Posting-Host: pender.ee.upenn.edu In article tomh.bbs@shark.cs.fau.edu (Tom Holroyd) writes: >vangeldr@cmgm.stanford.edu (Russ Van Gelder) writes: > >>2. What is the phenotype associated with lesions of the pedunculo- >>pontine tegmentum? Barbara Jones has performed these lesions in >>cats, resulting in a complete or almost complete loss of REM sleep. >>The animals seem fine. > >Deprivation of REM sleep causes death. A dead cat does not seem fine >to me. I wasn't familiar with this, so I just did a medline search. I suspected that Tom was wrong--that although there may be dire consequences to suppressing REMS in an anatomically "normal" animal, REMS may disappear in some pathologies without ultimately leading to death. My medline search turned up (among other things): Webster, HH, and Jones, BE. (1988). "Neurotoxic Lesions of the Dorsolateral Pontomesencephalic Tegmentum Cholinergic Cell Area in the Cat: Effects on Sleep-Waking States", Brain Res. 458(2):285-302. I haven't read it, but from what I saw in the abstract, REMS was always abnormal after these lesions, and it usually disappeared altogether immediately after the lesion. The animals went for up to a month (if I recall that right) without REMS, but there was no mention in the abstract that it ever disappeared permanently. I doubt that I'll take the time to pull up the paper--perhaps someone else (Russ?) can tell us more? >>One can theorize based on comparative phylogeny, but the functional >>experiments of knockout and overexpression (i.e. with carbachol >>injection into the pontine midbrain) haven't suggested any roles for >>REM sleep in the adult brain. Such experiments are only now being >>attempted in the developing brain (i.e. recent experiments by Gerry >>Vogel). > >There is no such thing as the pontine midbrain. The midbrain and the >pons are two different things. Come on, Tom... He may either be using the terminology a bit sloppily, or it may be that some people juxtapose the words as such to denote nuclei that span the two gross regions. Note the title of the paper I cited... How would you try to translate "pontomesencephalic"? >Again, deprivation of REM sleep causes death. This suggests that it >does do *something*. I would tend to agree that REMS has a purpose throughout life, but even if animals that are deprived of REMS do die (I'd like a reference to this, since the only place I've actually heard that such experiments were ever taken to that outcome was Star Trek The Next Generation), that does not mean that it is the lack of REMS that caused their death. The two mechanisms that I can recall that people have used to deprive animals (or people) of REMS are carbachol injections, or waking the subject when the EEG indicated that REMS was about to occur. If either of these types of experiments lead to the death of the subject, you'd be hard pressed to convince me that the lack of REMS was the only thing that could have caused that death. >Tom Holroyd & Bill Fortin >Center for Complex Systems >Florida Atlantic University >tomh@bambi.ccs.fau.edu Mickey Rowe (rowe@pender.ee.upenn.edu)