Cardiac autonomic activity during daytime nap in young adults.

The current study investigated both sympathetic and vagal autonomic patterns during a daytime sleep in 25 healthy adults (23.2 ± 2.4 years). Pre-ejection period (PEP; related inversely to beta-adrenergic sympathetic activity), the interval between consecutive R-waves (RR) and frequency-domain heart rate variability (HRV) were computed during pre-nap wakefulness and undisturbed sleep stages. Results showed sleep-related changes in RR and HRV measures, whereas PEP decreased significantly from pre-nap to sleep, showing no differences across sleep stages. Moreover, pre-nap PEP and HFnu (the normalized unit of the high-frequency component of HRV) were associated negatively with sleep latency and wake after sleep onset. These results indicate a marked autonomic output reduction during daytime sleep, with different stage-dependent fluctuations for sympathetic and vagal activity. Importantly, pre-nap autonomic activity seems to modulate subsequent sleep quality.

Sleep before and after learning promotes the consolidation of both neutral and emotional information regardless of REM presence.

Sleep may play a role in consolidating emotional memories. However, studies on the effects of REM sleep on negative vs. neutral memories have produced inconsistent evidence. Here, we assess the role of NREM and REM sleep before and after learning in promoting the consolidation of neutral and arousing pleasant and unpleasant memories. Forty-six (32 F) healthy university students were exposed to a set of pictures at 1:00PM (Session 1) and to an equivalent set at 4:45PM (Session 2). All the pictures in Session 1 and Session 2 were presented again, intermixed with new similar pictures at 5:15PM in a memory recognition task. Following Session 1, participants took a 90/120-min nap (NAP group), while 16 participants remained awake (WAKE group). Via polysomnographic recording, the NAP group was segregated into REM (N=14) and NoREM groups (N=16). Indices of memory consolidation for both stimuli presented before (discriminability of Session 1 pictures in Session 3) and after sleep (discriminability of Session 2 pictures in Session 3) were calculated. Memory consolidation for pictures presented both before and after the sleep period was higher in the NAP group as compared to the WAKE group, but no differential role of REM sleep emerged. A memory consolidation advantage was evident for neutral over pleasant (but not unpleasant) pictures. Taken together, these results indicate that a daytime nap (with or without REM sleep) facilitates consolidation of declarative memories presented before and after sleep irrespective of their valence.

Impaired off-line motor skills consolidation in young primary insomniacs.

Compelling evidence indicates that sleep can facilitate the off-line consolidation of declarative, perceptual, emotional and procedural memories. Here we assessed the sleep-related off-line consolidation of motor skills in 13 young primary insomniacs (23.31±2.5 yrs) compared to 13 healthy sleepers (24.31±1.6 yrs) using the sequential finger tapping task. During a training session insomniacs performed less correct sequences than controls. However, both groups exhibited similar on-line motor learning in the pre-sleep evening session. After a night of sleep, healthy controls improved their performance, indicating an overnight effect of sleep on motor skills consolidation. In contrast, insomniacs failed to exhibit a sleep-related enhancement in memory performance indicating impairment in the off-line motor skills consolidation process. Our results suggest that young adults with insomnia experience impaired off-line memory consolidation which seems not to be associated with reduced ability to acquire new motor information.

Facing emotions in narcolepsy with cataplexy: haemodynamic and behavioural responses during emotional stimulation.

Narcolepsy with cataplexy is a complex sleep disorder that affects the modulation of emotions: cataplexy, the key symptom of narcolepsy, is indeed strongly linked with emotions that usually trigger the episodes. Our study aimed to investigate haemodynamic and behavioural responses during emotional stimulation in narco-cataplexy. Twelve adult drug-naive narcoleptic patients (five males; age: 33.3 ± 9.4 years) and 12 healthy controls (five males; age: 30.9 ± 9.5 years) were exposed to emotional stimuli (pleasant, unpleasant and neutral pictures). Heart rate, arterial blood pressure and mean cerebral blood flow velocity of the middle cerebral arteries were continuously recorded using photoplethysmography and Doppler ultrasound. Ratings of valence and arousal and coping strategies were scored by the Self-Assessment Manikin and by questionnaires, respectively. Narcoleptic patients' haemodynamic responses to pictures overlapped with the data obtained from controls: decrease of heart rate and increase of mean cerebral blood flow velocity regardless of pictures' content, increase of systolic blood pressure during the pleasant condition, and relative reduction of heart rate during pleasant and unpleasant conditions. However, when compared with controls, narcoleptic patients reported lower arousal scores during the pleasant and neutral stimulation, and lower valence scores during the pleasant condition, respectively, and also a lower score at the 'focus on and venting of emotions' dimensions of coping. Our results suggested that adult narcoleptic patients, compared with healthy controls, inhibited their emotion-expressive behaviour to emotional stimulation, and that may be related to the development of adaptive cognitive strategies to face emotions avoiding cataplexy.

Relationship between cardiovascular resting state and visual attention.

INTRODUCTION: Cardiovascular features seem to modulate performance in attention tasks. METHODS: We investigated the relationship between blood pressure, resting heart rate and heart rate variability (HRV) and performance in a visuospatial attention task comparing normotensive and hypotensive young adults. CONCLUSIONS: We found an association between resting HRV and visual attention performance only in the normotensive group. In addition, we provided a further evidence of attention impairment in hypotensive individuals.

Impaired cerebral and systemic hemodynamics under cognitive load in young hypotensives: a transcranial Doppler study.

Reduced sympathetic outflow and deficits in cerebral hemodynamics have been considered as possible factors mediating the impaired cognitive performance in essential hypotension. However, the relationship between systemic blood pressure (BP), cerebral blood flow and cognitive functioning is still poorly understood. The present study was aimed at clarifying the physiological processes underlying cerebral and systemic hemodynamics in young hypotensives during cognitive engagement. Doppler sonography blood flow velocities in both middle cerebral arteries were measured from 17 hypotensives and 15 normotensives during a working memory task. Impedance cardiographic and BP measures were also recorded continuously. Lower increases in systolic and diastolic BP were observed in hypotensives. However, no evidence of lower sympathetic control was found for this group, as assessed by pre-ejection period. Flow velocity in middle cerebral arteries showed a lower increase in hypotensives throughout the task. Moreover, significant positive correlations between BP changes and blood flow velocities in middle cerebral arteries during the task were obtained for this group only, suggesting a less effective cerebral autoregulation. No difference was found between groups in task performance. Results suggest that during cognitive challenge hypotensives show impaired hemodynamic adjustments, both central and peripheral. However, such alterations do not directly affect cognitive performance, at least under moderate cognitive load.

Nocturnal cardiovascular activity in essential hypotension: evidence of differential autonomic regulation.

OBJECTIVE: Essential hypotension represents a form of chronic low blood pressure (BP) not explained by medical or orthostatic conditions. The pathogenesis of essential hypotension may involve sympathetic hypoactivation and other forms of autonomic dysregulation. The aim of the current study was to investigate autonomic and cardiovascular activity during sleep in individuals with essential hypotension. METHODS: A case-control study was conducted in 14 individuals with essential hypotension (mean [standard error] = 23.4 [0.6] years, all women) and 14 controls (mean [standard error] age = 22.2 [0.4] years, all women). The following measures were collected over a night of sleep: BP, heart rate (HR), stroke volume, cardiac output (CO), preejection period (PEP), total peripheral resistance, and time-domain measures of HR variability. RESULTS: Hypotensive participants had consistently lower BP, HR, and CO than did normotensives. Cardiac autonomic variables revealed enhanced parasympathetic tone (proportion of adjacent normal-to-normal intervals that differed in length by more than 50 milliseconds = 40.8 [6.3] versus 23.4 [4.5], p = .03) and reduced sympathetic drive in hypotensives (PEP = 99.4 [3.6] versus 86.1 [4.3], p = .02). Analysis of temporal profiles showed that HR, stroke volume, and CO decreased throughout the night in both groups, whereas PEP and HR variability increased. Unlike controls, BP remained essentially unchanged in hypotensives, as the decrease in CO was counterbalanced by a parallel rise in total peripheral resistance. CONCLUSIONS: These findings suggest that nocturnal cardiac sympathetic withdrawal combined with vagal hyperactivity is a characteristic of the autonomic regulation in essential hypotension.

Sleep onset and cardiovascular activity in primary insomnia.

The transition from wakefulness to sleep is characterized typically by a shift from sympathetic to parasympathetic regulation. Physiological functions, depending on the neurovegetative system, decrease overall. Previous studies have shown cardiovascular and electroencephalographic hyperactivity during wakefulness and sleep in insomniacs compared with normal sleepers, but there is very little evidence of this in the process of sleep onset. The purpose of this study was to compare cardiovascular and autonomic responses before and after falling asleep in eight insomniacs (who met DSM-IV criteria for primary insomnia) and eight normal sleepers. Non-invasive measures of heart rate (HR), stroke volume (SV), cardiac output (CO) and pre-ejection period (PEP) were collected by impedance cardiography during a night of polysomnographic recording. Frequency domain measures [low-frequency (LF), high-frequency (HF)] of heart rate variability (HRV) were also estimated. Decrements in HR and CO and increases in SV and HF normalized units (n.u.) were found in both groups after sleep onset compared with wakefulness. Conversely, PEP (related inversely to sympathetic ß-adrenergic activity) showed increases after sleep onset in controls, but remained unchanged in insomniacs. PEP was also significantly lower in insomniacs than in normal sleepers in both conditions. These data suggest that, whereas normal sleepers follow the expected progressive autonomic drop, constant sympathetic hyperactivation is detected in insomniacs. These results support the aetiological hypothesis of physiological hyperarousal underlying primary insomnia.

Not All Competitions Come to Harm! Competitive Biofeedback to Increase Respiratory Sinus Arrhythmia in Managers.

Despite the positive impact on achievement, competition has been associated with elevated psychophysiological activation, potentially leading to a greater risk of cardiovascular diseases. Competitive biofeedback (BF) can be used to highlight the effects of competition on the same physiological responses that are going to be controlled through BF. However, it is still unknown whether competition could enhance the effects of respiratory sinus arrhythmia (RSA)-BF training in improving cardiac vagal control. The present study explored whether competitive RSA-BF could be more effective than non-competitive RSA-BF in increasing RSA in executive managers, who are at higher cardiovascular risk of being commonly exposed to highly competitive conditions. Thirty managers leading outstanding private or public companies were randomly assigned to either a Competition (n = 14) or a Control (n = 16) RSA-BF training lasting five weekly sessions. Managers in the Competition group underwent the RSA-BF in couples and each participant was requested to produce a better performance (i.e., higher RSA) than the paired challenger. After the training, results showed that managers in the Competition group succeeded in increasing cardiac vagal control, as supported by the specific increase in RSA (p < 0.001), the standard deviation of R-R wave intervals (SDNN; p < 0.001), and root mean square of the successive differences between adjacent heartbeats (rMSSD; p < 0.001). A significant increase in the percentage of successive normal sinus beat to beat intervals more than 50 ms (pNN50; p = 0.023; η2 p = 0.17), low frequency (p = ≤ 0.001; η2 p = 0.44), and high frequency power (p = 0.005; η2 p = 0.25) emerged independently from the competitive condition. Intriguingly, managers who compete showed the same reduction in resting heart rate (HR; p = 0.003, η2 p = 0.28), systolic blood pressure (SBP; p = 0.013, η2 p = 0.20), respiration rate (p < 0.001; η2 p = 0.46), and skin conductance level (SCL; p = 0.001, η2 p = 0.32) as non-competitive participants. Also, the same reduction in social anxiety (p = 0.005; η2 p = 0.25), state (p = 0.038, η2 p = 0.14) and trait anxiety (p = 0.001, η2 p = 0.31), and depressive symptoms (p = 0.023, η2 p = 0.17) emerged in the two groups. The present results showed that managers competing for increasing RSA showed a greater improvement in their parasympathetic modulation than non-competing managers. Most importantly, competition did not lead to the classic pattern of increased psychophysiological activation under competitive RSA-BF. Therefore, competition could facilitate the use of self-regulation strategies, especially in highly competitive individuals, to promote adaptive responses to psychological stress.

Failure of language lateralization in schizophrenia patients: an ERP study on early linguistic components.

OBJECTIVE: In line with Crow's hypothesis, altered hemispheric lateralization of language would cause the main symptoms of schizophrenia. The present experiment aimed to demonstrate the loss of the hemispheric specialization for linguistic processing in schizophrenia patients at the level of early automatic evoked potentials (N150). METHODS: A sample of 10 outpatients with schizophrenia treated with low levels of neuroleptics and 10 matched healthy control subjects were administered 3 linguistic tasks based on stimulus pair comparisons (phonological, semantic and word-picture matching tasks). Laterality scores of early evoked potentials were analyzed during 2 time windows corresponding to the N150- and N400-like components. RESULTS: The patients failed to develop the typical left hemispheric N150 component evoked by the first word (S1), which was consistently achieved by the healthy control group in posterior sites (p < 0.01). The effect was specific and stable for linguistic stimuli. As well, for the N150 elicited by the target stimulus (S2), the patients exhibited a lack of linguistic lateralization. In the control task (word-picture matching task), in which S2 was a picture, the 2 groups revealed very similar bilateral recognition potentials. CONCLUSION: The results point to a failure of language lateralization in patients with schizophrenia, a deficit involving those linguistic networks automatically activated in the earliest phase of word recognition (N150). Consistent with the current view of schizophrenia, this finding may be related to lack of integration among specific processes and reduced interconnection of underlying linguistic networks.

Pre-motion positivity during self-paced movements of finger and mouth.

The present study investigated the role of pre-motion positivity in movement initiation and the reason why it is not reliably detectable in every study participant. Nineteen right-handed participants performed self-initiated simple movements of the right index finger and mouth while electroencephalography activity was recorded. Most of the participants showed a clear-cut pre-motion positivity with its characteristics varying as a function of the effector involved in the movement. The pre-motion positivity distribution was ipsilateral for finger movements and symmetrical for mouth movements. The results suggest that pre-motion positivity might represent a go-signal to initiate the movement and its occurrence might depend on movement initiation strategies.

Effects of sleep reduction on spatial attention.

To investigate the effects exerted by sleep loss on specific attentive components the performance to a simple reaction time task and to a cued reaction time task were recorded at regular intervals during days following either 8 or 3 h of uninterrupted sleep. Eleven subjects took part in the experiment. The results show that, notwithstanding a general reduction of alertness produced by sleep curtailment (as indicated by the increase of reaction times in the simple reaction time task), in the cued reaction time task only the reaction times to invalidly cued targets significantly increase, while no difference is observed when attention is summoned by a valid cue. This result suggests that the mechanisms underlying orienting of attention are differentially affected by the reduction of alertness level.

Selectively attending to natural scenes after alcohol consumption: an ERP analysis.

Alcohol effects on cognitive, emotional and behavioral processes have been linked to an impairment of attention. Because attention operates at the level of specific cognitive subsystems, recent studies demonstrated alcohol effects in specific post-perceptual processes such as response selection and working memory. Measuring event-related potentials, the present study focused on perceptual processes by utilizing a categorization task where participants had to decide whether briefly presented images contained an animal or not. Findings demonstrate an early differential ERP activity for target compared to non-target images, which was reduced after alcohol intoxication. Thus, alcohol intoxication had deleterious effects at the perceptual level of processing considered to reflect the interaction of top-down (category-related) and bottom-up (stimulus-driven) processes. In addition, post-perceptual processes were also impaired by alcohol intoxication.

Blood pressure changes highlight gender differences in emotional reactivity to arousing pictures.

The current study was aimed at investigating the effects of gender on the magnitude and patterning of blood pressure responses to specific pleasant and unpleasant, arousing visual stimuli. Systolic and diastolic blood pressure (SBP and DBP), as well as heart rate (HR) and skin conductance (SCR) responses were investigated during picture viewing in 21 female and 25 male students. The pattern of SCR and HR reactivity across emotional categories was found to be similar for men and women. Gender was found to be an effective moderator of BP responses specifically to sexual stimulus content, which prompted greater reactivity in men than in women. These findings extend prior research on gender differences in autonomic responding to emotional visual stimuli and suggest that BP changes might reflect sexual peripheral arousal more than other autonomic measures.

Reduced cerebral and cardiovascular hemodynamics during sustained affective stimulation in young women with chronic low blood pressure.

Although low blood pressure has been associated with lower affect and higher depressive symptoms in the elderly, the presence of possible impairment in emotional reactivity in chronic hypotensive individuals in early adulthood remains largely unexplored. Using a combination of transcranial Doppler sonography, beat-to-beat blood pressure recording and impedance cardiography we assessed central and peripheral hemodynamic changes in 15 undergraduate women with chronic hypotension (Age: 23.9 ± 2.7 years) and 15 normotensive controls (Age: 23.7 ± 3.1 years) during sustained exposure to pleasant, unpleasant and neutral pictures. Overall, systolic blood pressure (SBP) increased in normotensives and decreased in hypotensives during picture viewing as compared to baseline. Also, compared to normotensives, in hypotensives mean cerebral blood flow velocity increased to a lesser extent during the viewing of pleasant pictures and the magnitude of this increase was negatively associated with subjective emotional arousal. In addition, in hypotensives screening SBP was positively associated with valence rating of pleasant contents. These findings indicate a close association between chronic low blood pressure and reduced processing of pleasant stimuli in young adulthood.

Emotional information processing in patients with narcolepsy: a psychophysiologic investigation.

OBJECTIVES: Cataplexy is the key symptom of the narcoleptic syndrome. It is usually triggered by emotions, which play an important role in the manifestation and severity of the disease. Accordingly, we compared the psychophysiologic effects on patients with narcolepsy and healthy subjects of processing visual stimuli that have established emotional valences. METHOD: Eight drug-free patients with narcolepsy with severe cataplexy and 8 controls were studied. Fifty-four color pictures (pleasant, neutral, and unpleasant) selected from the International Affective Picture System were presented on a monitor to the subjects. The effects of exposure to the pictures were assessed in muscular (corrugator, zygomatic and mylohyoid electromyographic activity), autonomic (blood pressure, heart rate, and skin conductance responses) cognitive (scalp-recorded event-related potentials), and subjective (valence, arousal, and dominance by Self-Assessment Manikin) systems. RESULTS: The autonomic, muscular, and cognitive systems showed an attenuated reaction to visual stimuli in patients compared to controls. Furthermore, patients with narcolepsy showed the lowest responses when unpleasant pictures were presented. CONCLUSIONS: Our data suggest that, compared to the group of healthy subjects, patients with narcolepsy suffer from a temporal disadvantage in input processing, in particular, of unpleasant stimuli. The drawback exhibited by these patients suggests reduced reactivity of the aversive motivational system responsible for negative or unpleasant emotions.

Cortical brain responses to semantic incongruity and syntactic violation in Italian language: an event-related potential study.

The present experiment investigated cortical responses of native Italian subjects during reading of short sentences including semantic or morphosyntactic violations. Given the specificity of the Italian language in which the sequencing of words is relatively more free than in English or other languages, we investigated whether syntactic and semantic violations were able to elicit event-related potential (ERP) components similar to those found in other languages. Cortical potentials evoked by the anomalous target word were recorded at frontal, central and parietal electrodes. Results showed that, in Italian, semantic anomaly elicited a negative wave (N400) in the 400-500 ms time-window and syntactic error evoked a slower positive wave (P600) in the 500-700 ms time-window. Syntactic error also evoked a significant left anterior negativity in the 350-450 ms time-window, supporting the view that syntactic processes precedes semantic analysis. Thus, Italian language, notwithstanding its specificity, shows ERPs responses to semantic and syntactic violations, with effects, scalp distribution and latency similar to those found in German, Dutch and English. Results point to a cross-linguistic consistency of the semantic and syntactic ERP components associated with the detection of linguistic anomalies.

Blood phobia and spider phobia: two specific phobias with different autonomic cardiac modulations.

Cardiac reactions to two fear-related and one control film were compared in individuals high in spider or blood/injury fear. Twelve subjects in each phobic group were selected on the basis of their scores in the Spider or Mutilation Questionnaires and a semi-structured interview. Cardiac responses and self-reported affective ratings to the films were investigated. Sympathetic and parasympathetic cardiac influences were indexed by T-wave amplitude and respiratory sinus arrhythmia measured during film viewing. Basal parasympathetic cardiac control was also assessed during a paced breathing task. Results indicate differential autonomic modulation of cardiac responses for blood and spider phobics. Although each group reacted with marked cardiac activation to its feared stimulus, a sympathetic increase followed by withdrawal over time was found in blood phobics. Greater vagal tone at rest was present in blood phobics compared with spider phobics.

Heart rate variability during sleep as a function of the sleep cycle.

In this work, in order to evaluate whether autonomic differences distinguish REM sleep and NREM sleep through the whole sleeping period, statistical analysis on spectral power associated with low frequency and high frequency bands were performed on the whole polysomnographic recording, considering the sleep cycle as a unit of sleep. Our results from nine subjects show that power associated with low frequency is higher in REM sleep than in NREM sleep, while power associated with high frequency is significantly higher in NREM sleep than in REM sleep. Differences between REM sleep and NREM sleep are not of the same magnitude within the whole sleep episode and, independent of sleep stages, specific trends are observable in the autonomic control of heart rate during the night.

Working memory impairment and cardiovascular hyperarousal in young primary insomniacs.

We investigated memory performance and cardiovascular activity in 13 primary insomniacs (PI) compared to 13 good sleepers (GS). Cardiovascular and hemodynamic measures, including heart rate, pre-ejection period, and blood pressure, were continuously recorded at rest and during two memory tasks. PI showed working memory impairment under high cognitive load, but performed as well as GS in an easy memory task. In addition, PI exhibited markers of hyperarousal both at rest and during the execution of the two tasks. However, we failed to find a clear-cut relationship between cardiovascular hyperarousal and cognitive performance in insomniacs. Our data provide further evidence of both cognitive impairment and cardiovascular hyperarousal in primary insomnia, while not supporting the hypothesis of hyperarousal as a compensatory mechanism to overcome cognitive challenges.