Edit: Er, please do read this, I did spend some time looking for them. I'm not just trying to spoil the fun. There are unresolved problems with the memory consolidation hypothesis.
"Unequal stress effects of the platform technique of REM sleep deprivation and contradictory reports using similar deprivation and learning paradigms weaken the hypothesis that REM sleep is important for memory consolidation. The absence of major memory deficits in humans with drug- or lesion-in-duced REM sleep suppression further undermines the hypothesis, as does the lack of correlation between REM sleep time and learning ability in humans and across a wide range of mammals. However, sleep disruption occurring before learning will affect performance in learning tasks. This disruption is not due to the loss of sleep per se, but rather to the intrusions of sleep into waking duringthe learning task. In a similar way, sleep loss, because of the resulting impairment of concentration and sleep intrusions, will interfere with recall (78). Just as nutritional status, ambient temperature, level of stress, blood oxygenation, and other variables clearly affect the ability to learn, adequate sleep is vital for optimal performance in learning tasks. However, the existing literature does not indicate a major role for REM sleep in memory consolidation" [http://scholar.google.com/scholar?hl=en&lr=&q=cache:7owVbfW-0GUJ:a1162.fmg.uva.nl/~djb/edu/STUDENT_RESEARCH/Mirte_Cortlever/1058.pdf ][/color]
"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." [
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To confirm the role of sleep in memory trace processing, we need to realize four main goals. First, the characterization of task-dependent,
regionally specific brain activities during posttraining sleep should be pursued,
at different levels of cerebral organization. Second, it is necessary to demonstrate that these experience-dependent activities in sleep are ultimately related to long-lasting behavioral adaptation. Third, the specific role of sleep (i.e., sleep discharge patterns) in memory processing should be disentangled from other effects such as experimentally induced stress or circadian modifications. Fourth, the effects of SWS and REM sleep on the memory trace should be specified. A more comprehensive understanding of
the influence of sleep in memory processes could also reveal the commonalities with the role of sleep in other forms of brain plasticity, i.e., during neurodevelopment or during cerebral reorganization after brain damage.
[http://www.psychologie.hu-berlin.de/lehre/wulv38/userdata/Maquet01_S_sleep-memory.pdf ][/color]
