Biomedical subjects

G Tuozzi

Publications and source records attributed to G Tuozzi.

8 recordsLinked to original sources

PubMed2001

Active processing of declarative knowledge during REM-sleep dreaming.

The ability to process recently acquired knowledge is clearly maintained during sleep. Here we assess whether and how far the sleeper controls this processing (in a non-volitional and non-conscious manner). We posit that during sleep, the cognitive concerns of previous waking may guide access to, and processing of, items of declarative knowledge with which those concerns are associated. In a delayed recall task, before each of three sleep onsets in the same night, 12 subjects heard a different nonsense sentence. When awakened in rapid eye movement (REM) sleep, they were asked to report their dream experience and to recall the last sentence heard. Occurrences of incorporation into dream content were more frequent for this sentence than for the sentences heard before previous sleep onsets, and also more frequent than occurrences of similar contents in reports from a control night. However, the modalities of elaboration of dream contents did not vary. These findings indicate that cognitive concern can affect the accessing of recently acquired declarative knowledge during sleep, but not the modalities by which this is inserted into dream content. They also suggest that cognitive concern may help consolidate knowledge by increasing the likelihood of it being processed during sleep.

Adult↗

PubMed2001

Autonomic reactivity during viewing of an unpleasant film.

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.

Adult↗

PubMed1999

Endocrine and psychophysiological aspects of human adaptation to the extreme.

Human beings need to adapt to any extreme, unknown, or isolated environment. This adaptation requires changes in the normal regulation of psychophysiological homeostasis, as described in terms of stress reaction. The aim of the present study was to monitor the processes of human adaptation to cold and isolated areas in Antarctica during the 12th expedition of the Italian National Research Program. Nine healthy subjects (experimental subjects), members of the expedition, and nine controls in Italy, were studied over a period of 2 months. Anterior pituitary hormone secretion, insulin, and melatonin, plus routine blood test, blood pressure, and ECG were performed. In addition, psychophysiological correlates were also recorded before and after the expedition period. In experimental subjects results of metabolic data suggested the presence of an increased peripheral insulin sensitivity at the end of the permanence in the station and a significant increased of total cholesterol. Hematocrit also significantly increased due to the conditions of hypobaric hypoxia. Results of endocrine data showed a significant decrease (p < 0.05) of hormone levels, which was associated with a significant decrement of the Galvanic Skin Response (GSR) activity to a standardized cognitive stress. No significant differences were reported in the controls. The data suggest that the exposure to the extreme environment develops a possible psychophysiological mechanism(s) that decreases the individual arousal.

Acclimatization↗

PubMed1998

Story-like organization of dream experience in different periods of REM sleep.

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.

Adult↗

PubMed1996

Modifications of electrogastrographic activity during the viewing of brief film sequences.

The experiment assessed the effects of two film sequences, a pleasant documentary and a distressful scene, on electrogastrographic (EGG), electromyographic (EMG), and heart-rate responses during digestion by 30 healthy students. The physiological measures were recorded before and during the projection of each film sequence. At the end of each viewing period, subjects completed a self-rating questionnaire on the emotional experience. Analysis yielded a significant increase in heart-rate and EMG values during the viewing of the film sequences and a significant decrease in amplitude of the 3 cycles per minute (cpm) wave of EGG during the unpleasant film. The type of film sequence had also a statistically significant effect on the self-ratings of emotional states.

Adult↗

PubMed1992

Recall of mental sleep experience with or without prior verbalization.

We investigated whether verbalization of contents of mental sleep experience (MSE), just after awakening provoked during rapid eye movement (REM) sleep, facilitates subsequent recall in the morning. Twelve subjects were awakened four times in each of two experimental nights and alternately asked to recall, with or without concurrent verbalization, MSE contents preceding the awakening. In the morning, the subjects were asked to report MSEs both verbalized and nonverbalized during the night. If subjects were unable to provide a spontaneous morning report, they were prompted using a probe, which was the title given by the subjects to each MSE at the end of its verbalization or covert recall at night. Frequencies of spontaneous reports were high, regardless of whether MSEs had been previously verbalized or not. The proportions of spontaneous and probed reports were similar for verbalized and nonverbalized MSEs, but spontaneous morning reports were longer than probed ones, regardless of their previous verbalization. Spontaneous and probed morning reports corresponding to night reports shared similar linguistic structures (i.e., length of sentences and proportions of waking-related utterances, which are indicative of difficulty of retrieval for MSE contents) and had similar percentages of contents common to night and morning reports. These findings support the hypothesis that verbalization does not directly influence the further accessibility of MSE contents.

Adult↗

PubMed1989

Accessing previous mental sleep experience in REM and NREM sleep.

This study investigated the processes by which contents previously stored in memory are retrieved and inserted into mental sleep experience (MSE). MSE reports were collected from six subjects awakened three times on each of eight nights in two alternate sequences of awakenings (NREM-REM-NREM; REM-REM-REM). The occurrences of interrelations between contents of report pairs were scored using Clark's (1970) feature matching model. These were greater for same night pairs than for different night pairs, and did not differ with respect to sequence of awakenings or order of report pairs (first-second, second-third, first-third). Contents of previous MSEs, therefore, seem to be accessible in both sleep types for insertion into current MSE. The interrelated units were more frequently lexical than propositional, with more paradigmatic than syntagmatic relationships in report pairs from both sequences of awakenings. Thus, the re-elaboration of contents of previous MSEs seems to occur mainly at the level of single contents in both types of sleep, with similar modalities of processing.

Adult↗

PubMed1989

Gaze and eye-contact with anorexic adolescents.

Interviews with seven anorexic female adolescents and 12 control subjects were videotaped for analysis of visual behaviour. Individual looking and mutual gaze of subject and interviewer were coded by two judges and recorded through a two-channel push-button system of time recording for 10 min of interview segments. The results indicated that anorexics looked toward the eyes of the interviewer less frequently and more briefly than controls, and that mutual gazing was less common.

Adolescent↗