The case against memory consolidation in REM sleep

Hypnodude · November 27, 2002, 10:25pm

The case against memory consolidation in REM sleep
Vertes RP, Eastman KE
Behavioral and brain sciences 23 (2000) 793–1121

We present evidence disputing the hypothesis that memories are processed or consolidated in REM sleep. A review of REM deprivation (REMD) studies in animals shows these reports to be about equally divided in showing that REMD does, or does not, disrupt learning/memory. The studies supporting a relationship between REM sleep and memory have been strongly criticized for the confounding effects of very stressful REM deprivation techniques. The three major classes of antidepressant drugs, monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), and selective serotonin reuptake inhibitors (SSRIs), profoundly suppress REM sleep. The MAOIs virtually abolish REM sleep, and the TCAs and SSRIs have been shown to produce immediate (40-85%) and sustained (30-50%) reductions in REM sleep. Despite marked suppression of REM sleep, these classes of antidepressants on the whole do not disrupt learning/memory. There have been a few reports of patients who have survived bilateral lesions of the pons with few lingering complications. Although these lesions essentially abolished REM sleep, the patients reportedly led normal lives. Recent functional imaging studies in humans have revealed patterns of brain activity in REM sleep that are consistent with dream processes but not with memory consolidation. We propose that the primary function of REM sleep is to provide periodic endogenous stimulation to the brain which serves to maintain requisite levels of central nervous system (CNS) activity throughout sleep. REM is the mechanism used by the brain to promote recovery from sleep. We believe that the cumulative evidence indicates that REM sleep serves no role in the processing or consolidation of memory.

Hypnodude · November 27, 2002, 10:30pm

Somewhat related, but a different viewpoint:

One possible function of sleep: to produce dreams
Mancia M
Behavioural Brain Research 69 (1995) 203-206

Among the various functions of sleep, one is particularly significant for our mental life: that of producing dreams. This specifically human experience, which takes place only during sleep, is closely related with neurophysiological events. The coincidence between mental and biological events raises a complex epistemological question concerning the close relationship between dreams, viewed as a subjective experience and sleep, viewed as a vegetative experience which is possible to define from a behavioural, electrical, neurochemical and neurobiological viewpoint. In this presentation, the author criticizes Hobson and McCarley’s internal generator theory, according to which the pons activates the limbic structures responsible for the recovery of memory in dreams, on account of physiological and psychological reasons. The author puts forward a cognitive hypothesis, which considers dreams as a symbolic process of elaborating, interpreting and reorganizing in narrative sequences all the material accumulated in the memory during waking hours. The author proposes, therefore, a psychoanalytical model of dreaming, in which dreams constitute a way of representing the individual’s inner world with internal objects related with one another and with the Self.

alex · November 28, 2002, 10:40pm

I guess thats why its so easy to wake up from lds