yan king yin <y.k.y(at)lycos(dot)com> wrote in message news:9edigg$7gn5 at imsp212.netvigator.com...
> "maxwell" <mmmaxwell at hotmail.com>:
> >Not necessarily random. Let's stay with your idea-- of dreams as replay.
> >By definition, this is non-random activity.
> >Resolve this contradiction, please.
>> No, I was saying that dreams are not playback. I think dreaming is when
> random synaptic connections are generated. This is to prepare for mental
> activities the next day. According to the "clonal selection theory", new
> memory is formed by eliminating some of these random synapses.
>> If this hypothesis is correct, it would be different from the theory of
> "memory consolidation". One way to (inconclusively) settle this is
> to see whether memory capacity is limited by the amount of REM sleep
> during the previous night (I predict yes) and that the amount of REM
> sleep _after_ the presentation of materials would be largely irrelevant.
>> Using the "study for exam" example, i would suggest the amount of REM
> sleep _before_ studying should be most important.
Been done in rats:
Trains of sleep sequences are indices of learning capacity in rats [Research report]
Stefania Piscopo, Paola Mandile, Paola Montagnese, Mario Cotugno, Antonio Giuditta and Stefania Vescia
Behavioural Brain Research, 2001, 120:1:13 - 21
Abstract
In previous work dealing with the identification of four sleep sequences (SSW, SSPS, SSTSW and SSTSPS) in the baseline session of adult male Wistar rats [Mandile P, Vescia S, Montagnese P, Romano F, Giuditta A. Characterization of transition sleep episodes in baseline EEG recordings of adults rats, Physiol Behav 1996;60:1435-1439], we have shown that those containing an intervening episode of transition sleep (TS) strongly correlate with the number of avoidances scored the following day [Vescia S, Mandile P, Montagnese P, Romano F, Cataldo G, Cotugno M, Giuditta A. Baseline transition sleep and associated sleep episodes are related to the learning ability of rats, Physiol Behav 1996;60:1513-152]. More recently, clusters of sleep sequences (trains) separated by waking intervals longer than 60 s have been identified in the baseline session of the same rats [Piscopo S, Mandile P, Montagnese P, Cotugno M, Giuditta A, Vescia S. Identification of trains of sleep sequences in adult rats, Behav Brain Res, this volume], and distinguished in homogeneous or mixed trains according to the presence of a single sleep sequence or more than one sequence. Mixed trains have been further separated into trains containing the SSTSW sequence (+TSW trains) and trains lacking it (-TSW trains). Analysis of the distribution of variables of baseline trains (and of their sleep sequences and components) among fast learning (FL), slow learning (SL), or non-learning (NL) rats, indicates that variables of +TSW trains prevail in FL rats, while variables of -TSW trains prevail in NL rats. In addition, variables of +TSW trains correlate with the number of avoidances of the training session, while variables of -TSW trains do not significantly correlate, or show inverse correlations. Interestingly, sleep sequences such as SSW or SSTSW show direct or inverse correlations with avoidances depending on whether they are included in +TSW trains or in -TSW trains. The data are interpreted to suggest that the outcome of brain operations performed during a sleep sequence may selectively condition the appearance of later sequences within a time interval shorter than a given threshold. An analogous mechanism may be responsible for the aggregation of sleep components in sleep sequences.
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