Summary Presleep stimuli to be retained for further recall is often incorporated into dream contents. To establish whether processing for insertion into dream contents may improve consolidation, we compared the retention rate at delayed recall of contents resulting from incorporation of presleep sentence‐stimuli with those of other contents of the same dream experiences. We hypothesized that association with a cognitive task of recall facilitates access to recently acquired items of declarative knowledge such as presleep stimuli, and triggers the deep elaboration of their semantic features, which involves rehearsal. Twelve subjects were given a task of delayed recall for three nonsense sentences delivered once a time before each of the sleep (re‐)onsets over an experimental night. After each awakening in rapid eye movement sleep, subjects were asked to report dream experience and recall the sentence to be retained. In the morning, after spontaneous awakening, subjects were unexpectedly requested to again report their dream experiences and to recall the stimuli. Two pairs of judges independently identified possible incorporations of the stimuli, and parsed dream reports into propositional content units. The proportion of night reports with at least one incorporation of the stimulus delivered (i.e. valid incorporations) was higher than that of reports with contents similar to a stimulus(‐i) not yet delivered (forward pseudo‐incorporations) or delivered prior to an earlier sleep period (backward pseudo‐incorporations). The proportion of content units common to night and morning reports (considered to be better consolidated) was significantly higher for incorporated contents than for other contents, including pseudo‐incorporated contents. Instead, the retention at morning recall of words of sentence‐stimuli corresponding to incorporated contents was not significantly higher than that of other words. The better retention of incorporated contents provides a partial confirmation (that is, limited to the output of the processing) that a generation effect, which benefits retention of actively processed information, is operative during sleep as well as in waking.

The purpose of this study is to evaluate the short‐term effects on several physiological (arterial pressure and heart rate) and psychological (anxiety and aggressiveness) indexes of playing violent and non‐violent videogames in young adults. The study was carried out on a sample of 22 male participants. Subjects invited to participate in the study were recruited from a videogame leisure club. Before and during playing either a violent or non‐violent computer game, blood pressure and heart rate were measured. Before and after the game session, the subjects completed the State‐Anxiety Inventory‐Y (STAI‐Y) and the Buss–Durkee Hostility Inventory. The results of the study showed a range of short‐term effects of playing violent and non‐violent videogames on arterial pressure and on the state anxiety of subjects, but not on hostility measurements. More specifically, the group that played the violent videogames showed a significant increase in the state anxiety score at the end of the game, as compared to the pre‐game self‐evaluation, and an increase in the systolic blood pressure while the subjects were playing as compared to pre‐ and post‐game values. A decrease in diastolic blood pressure after playing any game was also found. Copyright © 2004 John Wiley & Sons, Ltd.

SUMMARY Four dream reports, collected from each of 16 subjects in an experimental night, were analysed using the criteria of Mandler and Johnson's story grammar. The experimental night was the first of the four nights where subjects had spontaneously given a dream report after each of the four awakenings planned in REM sleep. A multivariate analysis of covariance, taking the order of the nights where the experimental night occurred and the order of reports as factors, the number of stories per report as covariate and the number of statements in the setting, the number of statements in the event structure and number of episodes per story as dependent variables, showed that the greater length and complexity of reports collected in the second half of the night depends on a greater effectiveness of the dream production system rather than on a greater accuracy of recall. This increase concerns the organization of individual stories rather than the number of stories developed in a given time. These findings raise the issue of how dream production is re-triggered during REM sleep. To cast light on this issue, it seems important to establish whether and how the themes of the various stories developed in a given dream experience are interrelated. dream experience, mechanisms of dream production, REM sleep, story structure, thematic progression INTRODUCTIONOn the basis of both theoretical arguments (Foulkes 1982(Foulkes , 1985 and empirical evidence (Cipolli and Poli 1992; Cipolli Psychophysiological investigations on dreaming have shown et al. 1992a), at least three levels of functioning need to be consistently that dream experience, as reported after provoked posited in a model of dream production which can account awakening (mainly in REM sleep), is not only usually for the apparent coherence and complexity of many dreams: perceptually vivid and sometimes bizarre in content, but also (a) Recruitment of information relevant to the ongoing dream organized in a relatively lengthy and coherent narrative of quite experience, given that in almost all dreams various kinds plausible and complex events. Such a prominent characteristic of information (such as episodic memories and semantic suggests that dream experience is the result of a much more knowledge) appear to be processed in generating contents. complex production system than supposed in early studies. As postulated by multilevel models of dream production (for (b) Insertion of contents on a moment-by-moment basis, example, that of Foulkes 1982), the mechanisms supposedly providing for the sequential character of the ongoing operating at a higher level are in principle responsible for the dream. thematic progression of the dream experience, that is for the (c) Hierarchical organization of contents, providing for the organization of its contents into both linearly and hierarchically dream's coherence. ordered sequences of events linked by related characters and settings.A number of insights into the functioning of the mechanisms of the first and second levels ...

The effect of an aversive, high-arousing film on heart rate, respiratory sinus arrhythmia, and electrogastrographic activity (EGG) was investigated. Previous studies have indicated a larger heart-rate deceleration for visual stimuli depicting surgery or blood compared to neutral content, and this phenomenon is similar to the bradycardia observed in animals in response to fear. The heart-rate deceleration is clearly parasympathetically driven, and it is considered a general index of attention. An accurate index of cardiac vagal tone can be obtained by means of quantification of the amplitude of respiratory sinus arrhythmia. The relationship between cardiac vagal tone and EGG is complex, but animal research has shown that suppressing vagal activity dampens gastric motility. We have investigated whether a movie depicting surgery is associated with greater heart-rate deceleration, larger increase in respiratory sinus arrhythmia, and greater increase in EGG activity compared to a neutral movie. In addition, if both respiratory sinus arrhythmia and EGG are indices of vagal tone, a positive correlation between these physiological responses was expected. Analysis indicated an effect of the surgery movie on heart rate and respiratory sinus arrhythmia, but not on EGG activity. Moreover, the expected correlation was not found. Implications for future studies are discussed.

SUMMAR Y The level of procedural skills improves in normal individuals when the acquisition is followed by a period of sleep rather than wake. If sleep plays an important role in the consolidation process the advantage it provides should be reduced or delayed when its organization is altered, as in patients with chronic sleep disorders. To test this prediction in patients with narcolepsy-cataplexy (NC), who usually have a more fragmented organization of sleep than normals, we compared the initial, intermediate and delayed level of consolidation of visual skills. Twenty-two drug-naive NC patients and 22 individually-matched controls underwent training at a texture discrimination task (TDT) and were re-tested on the next morning (after a night spent in laboratory with polysomnography) and after another six nights (spent at home). TDT performance was worse in patients than controls at training and at both retrieval sessions and the time course of consolidation was different in NC patients (who improved mainly from next-day to 7th-day retrieval session) compared with controls. Moreover, the lessimproving patients at next-day retrieval had a wider disorganization of sleep, probably because of an episode of rapid eye movement (REM) sleep at sleep onset REM, on post-training night more frequently than more-improving patients. These findings suggest that the time course of the consolidation process of procedural skills may be widely influenced by the characteristics of sleep organization (varying night-by-night much more in NC patients than controls) during post-training night.