title: A new view of "dream enactment" in REM sleep behavior disorder.
abstract: Patients with REM sleep behavior disorder (RBD) exhibit increased muscle tone and exaggerated myoclonic twitching during REM sleep. In addition, violent movements of the limbs, and complex behaviors that can sometimes appear to involve the enactment of dreams, are associated with RBD. These behaviors are widely thought to result from a dysfunction involving atonia-producing neural circuitry in the brainstem, thereby unmasking cortically generated dreams. Here we scrutinize the assumptions that led to this interpretation of RBD. In particular, we challenge the assumption that motor cortex produces twitches during REM sleep, thus calling into question the related assumption that motor cortex is primarily responsible for all of the pathological movements of RBD. Moreover, motor cortex is not even necessary to produce complex behavior; for example, stimulation of some brainstem structures can produce defensive and aggressive behaviors in rats and monkeys that are strikingly similar to those reported in human patients with RBD. Accordingly, we suggest an interpretation of RBD that focuses increased attention on the brainstem as a source of the pathological movements and that considers sensory feedback from moving limbs as an important influence on the content of dream mentation.
authors.affiliation: Department of Psychological & Brain Sciences, The University of Iowa, Iowa City, IA 52242, USA; Department of Biology, The University of Iowa, Iowa City, IA 52242, USA; The DeLTA Center, The University of Iowa, Iowa City, IA 52242, USA. Electronic address: mark-blumberg@uiowa.edu.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Blumberg
authors.affiliation: Interdisciplinary Graduate Program in Neuroscience, The University of Iowa, Iowa City, IA 52242, USA.
authors.forename: Alan M
authors.initials: AM
authors.lastname: Plumeau
mesh_terms: D000818:Animals; D004325:Dreams; D006801:Humans; D009044:Motor Cortex / Q000503:physiopathology; D020187:REM Sleep Behavior Disorder / Q000503:physiopathology* / Q000523:psychology; D012895:Sleep, REM
keywords: Brainstem; Corollary discharge; Development; Motor cortex; Muscle atonia; Myoclonic twitching; REM sleep without atonia; Rapid eye movements; Sensorimotor integration; Superior colliculus