Alessandro Couyoumdjian

The electroencephalographic fingerprint of sleep is genetically determined: a twin study.

Humans have an individual profile of the electroencephalographic power spectra at the 8 to 16Hz frequency during non–rapid eye movement sleep that is stable over time and resistant to experimental perturbations. We tested the hypothesis that this electroencephalographic “fingerprint” is genetically determined, by recording 40 monozygotic and dizygotic twins during baseline and recovery sleep after prolonged wakefulness. We show a largely greater similarity within monozygotic than dizygotic pairs, resulting in a heritability estimate of 96%, not influenced by sleep need and intensity. If replicated, these results will establish the electroencephalographic profile during sleep as one of the most heritable traits of humans. Ann Neurol 2008

Physiological concomitants of perseverative cognition: a systematic review and meta-Analysis

Rumination about the past and worries about the future (perseverative cognition) are extremely common, although pervasive and distressing, dysfunctional cognitive processes. Perseverative cognition is not only implicated in psychological health, contributing to mood worsening and psychopathology but, due to its ability to elicit prolonged physiological activity, is also considered to play a role in somatic health. Although there is emerging evidence that such negative and persistent thoughts have consequences on the body, this association has not yet been quantified. The aim of this study was to meta-analyze available studies on the physiological concomitants of perseverative cognition in healthy subjects. Separate meta-analyses were performed on each examined physiological parameter. Sixty studies were eligible for the analyses. Associations emerged between perseverative cognition and higher systolic blood pressure (SBP) (g = .45) and diastolic blood pressure (DBP) (g = .51) in experimental studies, and higher heart rate (HR) (g = .28 and g = .20) and cortisol (g = .36 and g = .32), and lower heart rate variability (HRV) (g = .15 and g = .27) in experimental and correlational studies, respectively. Significant moderators were sex, ethnicity, type of induction used to elicit perseverative cognition, assessment of state versus trait perseverative cognition, focus on worry or rumination, duration of physiological assessment, and quality of the studies. With the exception of blood pressure, results were not influenced by publication bias. Results show that perseverative cognition affects cardiovascular, autonomic, and endocrine nervous system activity, suggesting a pathogenic pathway to long-term disease outcomes and clarifying the still unexplained relationship between chronic stress and health vulnerability.

The effects of sleep and sleep deprivation on task-switching performance

Neural systems of the prefrontal cortex (PFC) involved in executive functions are particularly vulnerable to sleep deprivation (SD). In this study, we investigated whether SD selectively affects specific components of the executive control processes involved in task‐switching performance. Two different tasks are performed in rapid and random succession in this procedure, so that the to‐be‐executed task may change from one trial to the next (switch trial), or may be repeated (repetition trial). Task‐switches are usually slower than task repetitions, giving way to the ‘switch cost’. One hundred and eight university students were assigned randomly to the sleep (S) or the SD group. Each of them was tested on a task‐switching paradigm before and after an experimental night (S or SD), and after one recovery night. SD impaired both task‐switching accuracy and speed. A higher proportion of errors and increased switch costs after SD have been observed, compared to normal sleep. Control analyses on switch and repetition trials showed that the SD group was significantly worse only on the switch trials. The effects of SD are reverted by one night of recovery sleep. It is concluded that the ability to adjust behaviour rapidly and flexibly to changing environmental demands, which relies on the functional integrity of the PFC, is impacted negatively by sleep loss.

Flexibility as the key for somatic health: From mind wandering to perseverative cognition

Mind wandering (MW) has been defined as the brains default mode of operation. It is a common experience, however, that this process can become maladaptive, and take the form of repetitive thoughts. We aimed to compare the cardiac and cognitive correlates of perseverative cognition (PC) and MW. Seventy-three healthy participants were engaged in two recall interviews designed to draw their attention to a neutral and a personally relevant negative episode. After each interview, participants performed a 20-min tracking task with thought probe while the electrocardiogram was continuously recorded. Perseverative cognition was associated with higher levels of cognitive inflexibility (slower reaction times, highest intrusiveness, efforts to inhibit), autonomic rigidity (low heart rate variability), and mood worsening compared to being focused on task or MW. Results suggest that MW fails to serve its adaptive function, and turns into a risk factor for health whenever it becomes a rigid and inflexible pattern (PC).

Cognitive rigidity is mirrored by autonomic inflexibility in daily life perseverative cognition.

Mind wandering (MW) can be persistent and therefore has been included in the repetitive thinking conceptualization. In line with a dimensional view of psychopathology, we hypothesized the existence of a MW-Perseverative Cognition (PC) continuum, where the latter is characterized by a rigid and defensive pattern with attentional, behavioral, affective, and autonomic perseverative manifestations. Ambulatory heart rate (HR) and variability (HRV) of 42 participants were recorded for 24h. Approximately every 30 min during waking, subjects reported their ongoing thoughts and moods using electronic diaries. MW was characterized by less effort to inhibit the thought and less interference with ongoing activities, absence of mood worsening, and higher HRV compared to PC. Worse sleep quality was predicted by higher levels of trait rumination and daily PC. Results suggest that MW and PC represent the functional and pathological ends of a continuum, respectively.

Dimensionality of self-compassion: translation and construct validation of the self-compassion scale in an Italian sample

Abstract Background: The construct of self-compassion is receiving increased attention due to its strong link to mental health. Nonetheless, many questions concerning its dimensionality and construct validity remain open. Aims: The purpose of this study was to evaluate the factorial structure and construct validity of the Self-Compassion Scale (SCS) in a sample of 424 Italian participants ranging in age from 17 to 65 years. Method: SCS was translated with a back-translation procedure and then administered through an on-line survey, along with measures of self-blame, subjective loneliness, emotion regulation, depression and anxiety. Results: Confirmatory factor analysis (CFA) confirmed the six-factor model both in the overall sample and in gender and age subgroups. CFA did not support the single higher-order factor of self-compassion, originally found by the author of the scale. Negative associations of Self-Kindness, Common Humanity and Mindfulness subscales with anxiety and depression were confirmed. Moreover, negative correlations of these subscales with self-blame, positive correlations with reappraisal and non-significant associations with expressive suppression and subjective loneliness were found, unveiling aspects of the construct not fully investigated in empirical research. Conclusions: Findings suggest that the SCS is a reliable tool but its dimensionality may vary according to different cultural contexts.

Pros and cons of a wandering mind: A prospective study

Mind wandering (MW) has recently been associated with both adaptive (e.g., creativity enhancement) and maladaptive (e.g., mood worsening) consequences. This study aimed at investigating whether proneness to MW was prospectively associated with negative health outcomes. At time 0, 21 women, 19 men; mean age = 24.5 (4.9) underwent a 5-min baseline electrocardiogram (ECG), a 20-min laboratory tracking task with thought probes, and personality questionnaires. At time 1 (1 year follow-up), the same participants underwent a 24-h Ecological Momentary Assessment characterized by ambulatory ECG recording and electronic diaries. First, we examined if the likelihood of being a “mind wanderer” was associated with specific personality dispositions. Then, we tested if the occurrence of episodes of MW in the lab would be correlated with frequency of MW in daily life. Finally, multiple regression models were used to test if MW longitudinally acted as a risk factor for health, accounting for the effects of biobehavioral variables. Among dispositional traits, the frequency of MW episodes in daily life was inversely associated with the capacity of being mindful (i.e., aware of the present moment and non-judging). There was a positive correlation between frequency of MW in the lab and in daily life, suggesting that it is a stable disposition of the individual. When differentiated from perseverative cognition (i.e., rumination and worry), MW did not predict the presence of health risk factors 1 year later, however, a higher occurrence of episodes of MW was associated with short-term adverse consequences, such as increased 24-h heart rate (HR) on the same day and difficulty falling asleep the subsequent night. Present findings suggest that MW may be associated with short term “side effects” but argue against a long term dysfunctional view of this cognitive process.

Intrapsychic and interpersonal guilt: a critical review of the recent literature.

Various authors hold that some emotions (i.e., moral emotions) have the function of orienting people toward ethical actions. In addition to embarrassment, shame and pride, the moral emotion of guilt is believed to affect humans’ behavior when they carry out transgressions that violate social and cultural standards. Over the past century, many studies (including controversial ones) have been conducted on guilt. In this study, we analyzed and summarized mainly the most recent literature on this emotion. On one side, the destructiveness of guilt is emphasized. It inflicts punishment and pain on individuals for their errors and can lead to psychopathology (e.g., depression). On the other side, it is described as a “friendly” emotion that motivates behavior adapted to social and cultural rules. How can this asymmetry be explained? Different existing views on guilt are presented and discussed, together with recent proposals, supported by research data. Finally, we discussed some systematic models that try to incorporate these different views in a single framework that could facilitate future researches.

Functional representation of 3d space in endogenous attention shifts

The aim of this study was to explore whether the attentional system, as far as an endogenous orienting is concerned, allocates resources along the sagittal plane and whether such a process is affected by, and is likely to be based on, different functional representations of 3D space in the brain. Several models make a main action-based distinction between representations of peripersonal space and of those extrapersonal space. Accordingly, if attention has to move from one representation to another, it should be possible to observe a decrease in performance during such a transition. To test this hypothesis three experiments were run in which participants performed a cued detection task. Cue stimuli were informative and were centrally located around the fixation point. Target stimuli were displayed at four different depth planes. In the first experiment, assuming that the border between the peripersonal space and the extrapersonal space was at 1 m from the observer, half the target stimuli were located in the peripersonal space and half in the extrapersonal space. The fixation point was located at 1 m from the observer. In the second experiment, the fixation point was moved at 2 m from the observer in order to rule out the possible effects of ocular motor programming. In the third experiment, in order to rule out effects related to the spatial layout of target stimuli (i.e., centre of mass effect) two target stimuli were located in the peripersonal space and six in the extrapersonal space. In all the experiments, besides a validity effect, we observed greater reaction times when attention shift was across spatial representations than when it was within the same representation. The implications for action-oriented models of attention are discussed.

Compassion at the mirror: Exposure to a mirror increases the efficacy of a self-compassion manipulation in enhancing soothing positive affect and heart rate variability

Abstract We tested whether a mirror could enhance the efficacy of a self-compassion manipulation in increasing soothing positive affect and heart rate variability (HRV). Eighty-six participants generated four phrases they would use to soothe and encourage their best friend. Second, they described an episode where they criticized themselves and were assigned to one of three conditions: (a) repeat the four phrases to themselves while looking at the mirror; (b) repeat the four phrases to themselves without the mirror; (c) look at themselves in the mirror without repeating the phrases. Participants in condition (a) reported higher levels of ‘soothing’ positive affect and HRV compared to participants in conditions (b) and (c). The effect of the ‘phrases at the mirror’ manipulation on soothing affect was mediated by increased common humanity. The mirror enhances the efficacy of this self-compassion manipulation in activating the soothing affect system connected with parasympathetic nervous system activity.