Biomedical subjects

Giuseppe Curcio

Publications and source records attributed to Giuseppe Curcio.

27 records · Page 2Linked to original sources

PubMed2003

Effect of total sleep deprivation on the landmarks of stage 2 sleep.

OBJECTIVE: To assess the effects of total sleep deprivation on sleep spindle and K-complex (KC) density. METHODS: Eight healthy male subjects (mean age=23.4 years) participated in the experiment: they slept in the laboratory for 3 nights (one adaptation, one baseline, one recovery); baseline and recovery night were separated by a period of 40 h of continuous wake. RESULTS: One night of total sleep deprivation caused a doubling of slow-wave sleep (SWS) amount, an increase of sleep efficiency and a reduction of the latencies of non-rapid eye movement (NREM) sleep stages during the recovery night. These effects were accompanied by a significant reduction in spindle density in the first sleep cycle of the recovery night. Mean KC density did not change as a result of total sleep deprivation, while KC density and inter-KC intervals showed linear trends across the first 4 sleep cycles, respectively decreasing and increasing. Finally, a clear evidence of an antagonist relationship between spindle and KC changes across sleep cycles was provided. CONCLUSIONS: The present study further supports the existence of a reciprocal relationship between SWS and sleep spindles, but fails to show an increase of KC density after total sleep deprivation. The opposite time courses of spindle and KC density across sleep cycles points to an antagonist relation between the two main phasic events of NREM sleep. The latter result, together with the increase of inter-KC distance and the decrease of KC density across subsequent sleep cycles, is consistent with the hypothesis of a role of the spontaneous KC as the "forerunner" of delta waves.

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PubMed2002

Are polysomnographic measures of sleep correlated to alexithymia? A study on laboratory-adapted sleepers.

OBJECTIVE: Since recent findings have pointed to a correlation between alexithymia and measures of poor sleep quality during the first night of adaptation to a sleep laboratory, the aim of the current study was to assess the same relation in healthy laboratory-adapted sleepers. As a further measure of rapid eye movement (REM) sleep characteristics, REM density was also measured. METHODS: Twenty-seven male subjects, without sleep or psychiatric disorders, filled out the 20-item Toronto Alexithymia Scale (TAS-20) and slept for two consecutive undisturbed nights. Polysomnography and REM density were measured in the postadaptation night. RESULTS: Alexithymia scores did not correlate significantly with any polysomnographic variable or with REM density. Only the Externally Oriented Thinking (EOT) subscale showed a negative association with REM latency. Multiple regression on selected sleep measures as predictors confirmed these results. CONCLUSION: Results do not extend to normal sleep the association previously found between alexithymia and a poor quality of sleep during the adaptation night in the sleep laboratory. The only polysomnographic measure showing an association, albeit little, with one facet of alexithymia was REM latency.

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PubMed2002

Regional differences of the temporal EEG dynamics during the first 30 min of human sleep.

The analysis of the time-course of different EEG bands during the first sleep cycle has up to now taken into account mostly central derivations. In the present study, we assessed the topographical differences of the time-course of different EEG bands during the first 30 min of sleep, by analysing the EEG power from four different scalp locations along the antero-posterior axis. Correlation of EEG bands time courses within and between each derivation has also been evaluated. Delta-theta (1-6.75 Hz) and alpha (7-10.75 Hz) activities exhibited an antero-posterior gradient with maximal power on the frontal lead and increased at all derivations in the first 15 min and 5 min periods, respectively. Then alpha power decreased at all derivations, but the frontal. Sigma EEG power (11-15.75 Hz) showed a coherent behavior over the four derivations, characterized by a steep increase in the first 3-5 min of sleep, followed by a stable decreasing trend. Beta power (16-25.75 Hz) linearly decreased only on the more posterior derivations, abruptly increasing on the frontal lead after a 15 min interval. Correlations between delta-theta and alpha band were higher on the frontal derivation. Moreover, frontal alpha was strongly related to delta-theta activity on all the four derivations, while occipital alpha was not. The negative correlations between delta-theta and beta time courses were very high on all derivations but the frontal one. This study shows the existence of topographical differences in the time-course of different EEG bands during the first 30 min of sleep. The peculiar behavior of the alpha and beta EEG bands over the frontal derivation indicates the need to re-consider the functional role of traditional EEG bands during sleep.

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PubMed2002

Cortical EEG topography of REM onset: the posterior dominance of middle and high frequencies.

OBJECTIVES: To investigate the brain topography of human sleep electroencephalography (EEG) along the antero-posterior axis during rapid eye movement sleep (REM) onset and REM offset, by means of a quantitative analysis of EEG changes. METHODS: EEG power values were calculated across a 1.00-25.75 Hz frequency range during time intervals preceding and following REM onset of the first 4 sleep cycles of 10 normal subjects. Topographical changes were assessed through Fpz-A1, Fz-A1, Cz-A1, Pz-A1, Oz-A1 recordings during NREM-REM-NREM transitions. RESULTS: The temporal dynamics of REM onset is characterized by a specific topographical pattern of EEG changes with a relatively higher EEG activity at posterior sites: Oz does not show any clear change within the alpha and beta frequencies, at variance with the marked reductions of the other sites, while it shows reductions of power in the delta/theta and sigma frequency ranges of smaller size as compared to the other sites. REM offset does not appear as a mirror-image of REM onset, since the pattern of regional differences characterizing the NREM sleep preceding REM onset is not fully reached. CONCLUSIONS: REM onset is characterized by a general change of EEG activity toward a relative occipital diffusion of power, specifically distinguished by a posterior dominance of middle and high frequencies.

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PubMed2002

Topographical changes in N1-P2 amplitude upon awakening from recovery sleep after slow-wave sleep deprivation.

OBJECTIVES: To assess auditory evoked potentials (AEPs) before sleep and upon 3 awakenings during an undisturbed baseline night and to compare them to AEPs during a night characterized by a recuperative increase in the amount of slow-wave sleep (SWS) as a consequence of two consecutive nights of selective SWS deprivation. METHODS: Ten male subjects slept in the laboratory for 6 consecutive nights. The first 2 nights were undisturbed. The 3rd night was considered as baseline. During the 4th and 5th nights, selective SWS deprivation was obtained by means of acoustic stimulation. The 6th night was a recovery. The data reported here were collected during the baseline and the recovery night. Subjects were awakened 3 times: after 2 h, 5 h (nocturnal awakenings) and 7.5 h (final morning awakening) of sleep, respectively. All the awakenings were carried out from stage 2. The AEP recordings were carried out in bed, while subjects were performing a simple auditory reaction time task. RESULTS: The amplitude of the N1-P2 complex decreased upon the first awakening of the baseline night as compared to pre-sleep wakefulness levels; during the recovery night, the decrease of N1-P2 amplitude was present also upon the second and final awakening. N1 latency increased upon the two nocturnal awakenings regardless of the night, while P2 latency was not affected. Moreover, the N1-P2 amplitude increased during recovery at the frontal midline derivation as compared to baseline, while it decreased at Pz and Oz. CONCLUSIONS: The N1-P2 amplitude and, to a lesser extent, the N1 latency, are sensitive in showing a state of brain deactivation during the sleep-wake transition. The decrease of N1-P2 amplitude at the parieto-occipital locations during recovery is coherent with the hypothesis of a functional link between SWS amount and cortical hypoarousal upon awakening. The unexpected increase of the same variable at Fz can be interpreted as the effect of a compensatory effort of the frontal areas for the increased homeostatic drive for sleep during the recovery night.

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PubMed2002

Interhemispheric asymmetry of human sleep EEG in response to selective slow-wave sleep deprivation.

Recent evidence suggests that the human sleep electroencephalogram (EEG) shows regional differences over both the sagittal and coronal planes. In the present study, in a group of 10 right-handers, the authors investigated the presence of hemispheric asymmetries in the homeostatic regulation of human sleep EEG power during and after selective slow-wave sleep (SWS) deprivation. The SWS deprivation was slightly more effective over the right hemisphere, but the left hemisphere showed a markedly larger increase of EEG power in the 1.00-24.75 Hz range during recovery-night non-REM sleep, and a larger increase of EEG power during both deprivation-night and recovery-night REM sleep. These results support the greater need for sleep recuperative processes of the left hemisphere, suggesting that local sleep regulation processes may also act during REM sleep.

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PubMed2002

Regional differences of the human sleep electroencephalogram in response to selective slow-wave sleep deprivation.

The purpose of this study was to assess the topographic changes in sleep recuperative processes in response to selective slow-wave sleep (SWS) deprivation. SWS was suppressed on two consecutive nights by means of acoustic stimulation. The electroencephalogram (EEG) power of baseline, deprivation and recovery nights was analysed in 1 Hz bins. During the SWS deprivation nights, large decreases of EEG power were found at frontopolar, central and parietal derivations encompassing the delta, theta and alpha range, while only slow delta (0.5-2 Hz) was affected at the frontal derivation. Recovery sleep was characterized by a generalized increase of power during non-REM sleep encompassing the delta, theta and alpha bands, with a clear antero-posterior gradient. The coherent behaviour of different EEG bands with traditionally different electrophysiological meanings during non-REM sleep suggests that, in light of the recent advances in sleep neurophysiology, a re-examination of the functional role of EEG rhythms during sleep is needed. The 'resistance' to selective SWS deprivation of the frontal area, together with its larger increase of EEG power during recovery, may be interpreted as a sign of a greater sleep need of the frontal cortical areas, confirming that some aspects of the regulatory processes of human sleep are local in nature and may show use-dependent characteristics.

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PubMed2002

The cyclic alternating pattern decreases as a consequence of total sleep deprivation and correlates with EEG arousals.

The aim of this study was to assess the sensitivity of the cyclic alternating pattern (CAP) parameters to the increased need for recuperation that follows one night of sleep deprivation. Nine normal male subjects were recorded for 3 nights [adaptation, baseline (BSL) and recovery (REC)]. BSL and REC nights were separated by a 40-hour sleep deprivation. Recovery after sleep deprivation was characterized by a decrease in stage 1, stage 2 and sleep latency, and an increase in slow wave sleep (SWS) and the sleep efficiency index, while rapid eye movement (REM) and non-REM (NREM) time did not differ as compared to BSL sleep. CAP parameters were significantly affected by sleep deprivation, and the main results were the following: (1) the CAP rate (time spent in CAP phases/NREM time) significantly decreased from 38.85 to 31.47%, and (2) within phase A subtypes, there was a significant decrease in A3 subtypes (from 38.11 to 19.57). Furthermore, the number of arousals scored according to American Sleep Disorders Association rules strongly correlated with A3 subtypes during both the BSL (r = 0.79) and REC nights (r = 0.95). These results indicate that recuperative processes after sleep deprivation are also associated with a lesser arousal instability as defined by the reduction of the CAP rate, which is strongly correlated with EEG arousals.

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PubMedDate not supplied

Alexithymia and dream recall upon spontaneous morning awakening.

OBJECTIVE: The issue of a quantitative and qualitative impoverishment of dream activity in alexithymic subjects was assessed by analysis of the 14-day dream reports of two groups of accurately selected alexithymic and nonalexithymic subjects. METHODS: Ten alexithymic and 10 nonalexithymic women were selected from a larger sample of 160 undergraduate students. The transcriptions of their audio-recorded dream reports on 14 consecutive morning awakenings were compared with regard to their length and emotional content. Self-ratings obtained from sleep and dream diaries were further considered to assess between-groups differences in dream recall frequency and in the emotional valence, vividness, and bizarreness of dreams. RESULTS: Dream recall frequency and mean length of dream reports were lower in alexithymic than in nonalexithymic subjects. There were no significant between-groups differences in emotional valence, vividness, bizarreness, and emotions scored according to the Hall and Van de Castle coding system. CONCLUSIONS: The results suggest a general difficulty of alexithymics in accessing (recalling) their dreams.

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