COVID-19-related social isolation and symptoms of depression and anxiety in young men in Poland: Does insomnia mediate the relationship?

The need for physical distancing due to COVID-19 mitigation efforts forced prolonged social isolation, which may affect sleep and lead to mental health problems. Previous research has shown that young adults are particularly vulnerable to psychological stress caused by social isolation, the negative psychological impact of the pandemic, and greater frequency and severity of sleep problems. Therefore, the main goal of the present study was to examine whether insomnia could constitute a mediation mechanism that explains the relationship between social isolation experienced during the COVID-19 pandemic and mental health outcomes (depression and anxiety) reported up to 1.5 years later. The study was conducted among young (M±SD; 24.08±3.75) men (N = 1025) in Poland. Data were collected by means of self-report questionnaires, including The Social Isolation Index, The Athens Insomnia Scale, The State-Trait Anxiety Inventory (STAI-S) and Beck's Depression Inventory (BDI-II). The results show that insomnia mediates the relationships between social isolation and both anxiety and depression. The current findings emphasize the role of insomnia in the relationships between social isolation experienced during COVID-19 and negative emotional states. From a clinical perspective, the results suggest that implementing therapeutic components that address social isolation in insomnia treatment programs may prevent the development of depression and anxiety symptoms among young men.

Emotion regulation strategies and mental health symptoms during COVID-19: the mediating role of insomnia.

OBJECTIVES: COVID-19 has become a major source of stress for people around the world. Stressful life events play a role in the pathogenesis of sleep disorders such as insomnia which is considered a risk factor for anxiety and depression. Emotion regulation is an important factor linked with sleep and mental health problems. Therefore, the main goal of the present study was to examine whether insomnia could constitute a mediation mechanism that explains the relationship between emotion regulation strategies (rumination, reappraisal, suppression) and stress-induced mental health outcomes during the COVID-19 pandemic. MATERIAL AND METHODS: The cross-sectional study was conducted among young (M±SD 24.8±2.24) individuals (N = 281, 85.4% women) during the time of the third wave of infections in Poland. Data were collected by means of selfreport questionnaires, including the Emotion Regulation Questionnaire; Cognitive Emotion Regulation Questionnaire; Athens Insomnia Scale; Depression, Anxiety and Stress Scale. The direct and indirect effects of emotion regulation strategies on depression, anxiety, and stress were calculated using a bootstrap estimation technique. RESULTS: All analyzed indirect effects were significant. The results show that insomnia mediates the relationships between all 3 emotion regulation strategies and stress, anxiety and depression. CONCLUSIONS: The presented results shed the light on the role of insomnia on the relationships between emotion regulation strategies and emotional states experienced during the COVID-19 pandemic. Additionally, the present study suggests that educational and therapeutic interventions aimed at improving emotion regulation might be useful for improving symptoms of insomnia and, through it, symptoms of affective disorders. Int J Occup Med Environ Health. 2023;36(1):151-59.

Differences in psychological distress, resilience and cognitive emotional regulation strategies in adults during the Coronavirus pandemic: A cross-cultural study of Poland and Spain

El objetivo de este estudio transcultural fue analizar las diferencias en resiliencia, estrategias de regulación cognitiva de las emociones (CERS) y distress psicológico durante la pandemia del COVID-19 en Polonia y España. Método. Se realizó una encuesta online en una muestra de 1,182 adultos. Se llevó a cabo un análisis MANOVA para examinar las diferencias en las variables estudiadas entre estos países. Esto fue seguido de un análisis MANCOVA controlando el sexo y la edad. Se realizaron análisis de regresión lineal segmentados por país con el fin de identificar modelos predictivos de distrés psicológico. Resultados. La población polaca se caracterizó por niveles más altos de ansiedad, menos resiliencia y más uso de CERS desadaptativas durante el confinamiento. La población española sufrió más estrés pero utilizó CERS adaptativas y fue más resiliente. La edad y el sexo femenino aparecieron como factores de riesgo de malestar psicológico en España. Se encontró que los modelos de predicción de distrés psicológico fueron diferentes en ambos países: las CERS adaptativas fueron predictivas en España y la resiliencia fue predictiva en Polonia. Conclusiones. Este estudio podría guiar en iniciativas para la promoción del bienestar psicológico como vía para prevenir trastornos psicopatológicos durante la pandemia.(AU)

Background.The objective of this cross-cultural study was to ana-lyze the differences in resilience, cognitive emotion regulation strategies (CERS), as well as psychological distress during the COVID-19 pandemic between Poland and Spain. Method.An online survey was conducted on a sample of 1,182 adults. A MANOVA analysis was carried out to examine the differences in the studied variables between these countries. This was followed by MANCOVA analysis to control for gender and age. Linear re-gression analyses segmented by country were conducted in order to identi-fy psychological distress prediction models. Results.Polish population was characterized by higher levels of anxiety, less resilience and more maladap-tive CERS during the lockdown. Spanish population was more affected by stress but used more adaptable CERS and was more resilient. Age and fe-male gender appeared as risk factors of psychological distress in Spain. The psychological distress prediction models were found to be different be-tween both countries: adaptive CERS was predictive only in Spain, and re-silience was predictive only in Poland. Conclusions.This study could guide in initiatives for the promotion of psychological well-being as a way to pre-vent psychopathological disorders during the pandemic.(AU)

Cognitive emotion regulation strategies mediate the relationships between Dark Triad traits and negative emotional states experienced during the COVID-19 pandemic.

COVID-19 has become a major source of stress as it puts individuals at risk of a range of mental health problems. Personality traits may predispose people to use adaptive or maladaptive coping strategies that lead to different health-related outcomes. The goal of the present study was to examine whether the use of distinct coping strategies during this stressful COVID-19 outbreak mediates the relationships between Dark Triad (DT) traits and stress, depression, and anxiety. The study was conducted in Poland (N = 1086) and Spain (N = 582), thus cross-culturally validated measures were used to assess depression, anxiety and stress (DASS-21), cognitive emotion regulation strategies (CERQ) and socially aversive traits covered by DT (Dirty Dozen scale). The study shows that maladaptive CERS mediates the relationships between narcissism/Machiavellianism and stress, anxiety and depression. Additionally, adaptive CERS mediates the relationship between psychopathy and depression. The results provide a better understanding of the mediating role of CERS on the relationships between DT traits and the stress, anxiety and depression experienced during the COVID-19 pandemic.

Psychophysiological Characteristics of Burnout Syndrome: Resting-State EEG Analysis.

INTRODUCTION: The consequences of chronic work-related stress are related to various emotional, cognitive, and behavioral symptoms. Occupational burnout as a complex syndrome is characterized by exhaustion, cynicism, and lower professional efficacy. Moreover, the growing amount of research on the neural correlates of burnout broadens the existing knowledge on the mechanisms underlying this syndrome. AIM OF THE STUDY: The aim of the study is to explore possible differences in brain activity between burnout and nonburnout employees. Frequency-specific EEG power analyses in a resting-state condition in burnout subjects and controls are presented. MATERIALS AND METHODS: Burnout employees (N=46; 19 men) were matched with the control group (N=49; 19 men; mean age: 36.14 years, SD=7.89). The Maslach Burnout Inventory-General Survey (MBI-GS) and the Areas of Worklife Survey (AWS) scale were used to measure burnout symptoms and work conditions, respectively. A 256-channel EEG (EGI System 300) was used to collect psychophysiological data. A repeated measures ANOVA was performed with condition (eyes-open vs. eyes-closed) and region (6 levels: extracted scalp regions) factors; burnout (2 levels: burnout vs. no burnout) was the grouping factor. RESULTS: A significant difference was observed only in the alpha frequency band: the burnout group revealed significantly lower alpha power in the eyes-open condition compared to the controls (p<0.05). The correlation analysis revealed that gender may significantly change the pattern of relations between EEG spectral characteristics and burnout symptoms. CONCLUSIONS: Reduced alpha power in burnout individuals suggests cortical hyperactivity and may be related to greater mental effort and the possible development of compensatory mechanisms by burnout subjects.

Occupational burnout and its overlapping effect with depression and anxiety.

OBJECTIVES: The problem of defining burnout concerns its overlapping effect with other syndromes and disorders, such as depression and anxiety. Additionally, some individual characteristics influence susceptibility to burnout (e.g., neuroticism). Therefore, the question arises whether burnout is or is not a distinct syndrome. The aim of the study is to compare 2 distinct burnout measures by analyzing their connections with organizational and individual variables. MATERIAL AND METHODS: The study was conducted in the Institute of Applied Psychology at the Jagiellonian University, Kraków, Poland on a group of employees (N = 100; 40 men; mean age 36.03 years). All participants completed 2 burnout scales: the Maslach Burnout Inventory - General Survey (MBI-GS) and the Link Burnout Questionnaire (LBQ). Organizational and individual factors were controlled with Areas of Worklife Survey, State-Trait Anxiety Inventory, NEO Five-Factor Inventory and Beck's Depression Inventory scales. A structural equation path model was created to quantify the relations between organizational factors and burnout, as well as to control the individual factors of anxiety, neuroticism and depression. RESULTS: The results indicate high compatibility between MBI-GS and LBQ on burnout diagnosis. The MBI-GS and LBQ revealed stronger connections with organizational context and individual characteristics, respectively. Depression explains dimensions of exhaustion (MBI-GS, LBQ), sense of disillusion (LBQ), neuroticism-exhaustion (MBI-GS); anxiety explains sense of professional inefficacy (LBQ). CONCLUSIONS: Besides organizational variables, individual characteristics also play an important role in explaining burnout syndrome. Exploring the 2 burnout models has revealed that depression is an important determinant of exhaustion. Cynicism and relationship deterioration have consistently been explained only by organizational context. Int J Occup Med Environ Health. 2019;32(2):229-44.

Dynamics of error-related activity in deterministic learning - an EEG and fMRI study.

There is a close relationship between progress in learning and the error-monitoring system. EEG and fMRI studies using probabilistic learning have revealed the distinct dynamics of this system after response and feedback, i.e. an increase of error-related and a decrease of feedback-related activity in the anterior cingulate cortex (ACC). Based on the existing theories, it can be presumed that during deterministic learning feedback-related activity in ACC would also increase. Since these assumptions have not yet been confirmed, it can be only speculated based on the data from the probabilistic paradigms how the information is being integrated within the ACC during deterministic learning. Here we implemented the Paired Associate Deterministic Learning task to the EEG and fMRI experiments. The analysis of EEG data showed a significant increase in the amplitude for both ERN and FN. Similarly, the fMRI results showed an increase in response-related and feedback-related activity of the ACC in erroneous trials. Our findings are in line with the current theories of ACC function: increasing ACC activity can be linked to the detected discrepancy between expected and obtained outcomes. We argue that expectancy violations in the course of deterministic learning are signalled by both, internal and external evaluation system.

Stimulus, response and feedback processing in burnout - An EEG study.

Professional burnout is a syndrome that is characterized by psychophysical or emotional exhaustion, depersonalization and diminished professional efficacy. Research on burnout often indicates deficits in cognitive functioning, such as memory problems or impaired voluntary control over attention. Many studies focus on behavioral and self-reported measures of burnout consequences; however, a limited number have focused on its consequences on a neural level. In our EEG study (N = 88; 42 with burnout), we analyzed the event-related potentials (ERP) associated with stimulus, response and feedback processing using two experimental procedures - the Go/NoGo Task and the Doors Task. Our results show that while there is no difference in performance between burnout and control group, on the neural level there are significant differences in all analyzed aspects of information processing: stimulus, response and feedback processing, indicated by the N200 and P300, Pe, and P200 event-related potentials, respectively.

When three is greater than five: EEG and fMRI signatures of errors in numerical and physical comparisons.

Unravelling the neural mechanisms, which determine performance accuracy, is one of the key concepts in cognitive neuroscience. When compared to correct responses, shorter reaction times are commonly observed behavioural feature of errors committed in typical conflict tasks. Yet, little is known about the origins of this phenomenon. In this study, EEG and fMRI experiments were conducted using the numerical version of the Stroop paradigm, which yielded unique behavioural outcomes. Particularly, errors in numerical comparison had shorter reaction times than correct trials, whereas physical comparison resulted in the opposite pattern. This criss-crossing interaction effect was used as a marker when exploring time-courses of brain activity. Group independent component analysis was applied to neurophysiological data and event-related analysis was conducted on the components' time-courses. Results revealed one centro-parietal EEG component and one temporo-parietal fMRI neural network, which exhibited significant task and accuracy interactions. Showing linear increase that peaked right after the response onset, the activity of centro-parietal EEG component was linked to the decision variable signal, which reflects a process of accumulating evidence until reaching an action-triggering threshold. Both amplitude measurements and linear fits to the signal provided evidence for distinctive characteristics between numerical and physical comparisons, thereby explaining the behavioural outcomes: errors are committed due to accumulation of evidence in favour of the other (wrong) task instruction. The architecture of the temporo-parietal network, which comprises bilateral inferior temporal and intraparietal regions, is highly consistent with the recently established core "number network". These findings link perceptual decisions with the generalized magnitude system and impart novel insights into the neural determinants of errors in humans.

Chronotype description: In search of a solid subjective amplitude scale.

The term "subjective circadian amplitude" refers to the range or the distinctness of diurnal variations of arousal, that is, the awareness (or lack thereof) of difference between hyper- and hypo-activation phases, the ability to volitionally modulate one's own psychophysiological state, the strength of morning-evening preferences and flexibility of the rhythm or perceived stability of the circadian phase. The complexity of this construct is the source of difficulties in research and measurement. The psychometric features of distinctness subscales of the Chronotype Questionnaire and the Caen Chronotype Questionnaire are not satisfactory. In search of the solid subjective amplitude (AM) scale, the Rasch analysis was applied to test 12 behavioral descriptors of circadian rhythm distinctness. The results of the Rasch factor analysis showed unidimensionality of the construct. Rating scale diagnostics of the subjective amplitude scale indicated good fit. However, answer category 3 (neutral agreement on the Likert-type, five-point scale) never emerged as modal and step calibrations negated the monotone incrementality of the scale. Rescoring the scale into a four-point category measure yielded satisfactory OUTFIT indices ranging from 0.90 to 1.10. The newly designed AM scale comprised four items referring to small and four to the large amplitude. The four-point answer option was adopted. The data from 234 subjects (53% women; mean age 31.63 ± 12.99 years) were gathered and analyzed. Percent of the total variance explained in Component Analysis (PCA) reached 45.7% (morningness-eveningness (ME) scale - 26.5%, AM scale - 19.2%). There was no correlation between ME and AM scales (Pearsons's simple correlation coefficient r = -0.018). The internal reliability of the AM scale, as measured with Cronbach's alpha coefficient, proved to be satisfactory: 0.72 (for ME scale - 0.86). Item-total correlations in the AM scale ranged from 0.433 to 0.774 and were significant at p < 0.001. Confirmatory factorial analysis of AM scale indicated mediocre fit: chi-square/degree of freedom = 3.00, root mean square error of approximation = 0.09, standardized root mean square residual = 0.08, comparative fit index = 0.87, Tucker-Lewis index = 0.82. However, the results of Rasch analysis showed good fit statistics for all items: OUTFIT mean squares range from 0.63 to 1.34 and INFIT mean square range from 0.64 to 1.40. All observed values were ≤1.4, which confirmed the new scale as being unidimensional.f If to consider the chronotype in the context of the classical Borbely's two-process model of sleep regulation, it may be assumed that ME dimension relates to the tempo of increasing of sleep pressure during the day, that is, it reflects the homeostatic component of the diurnal rhythm of sleepiness. As to the amplitude, it may be supposed that more distinct rhythm (large amplitude) stands for greater vulnerability to the time of day - it resounds the circadian component of the sleep proneness. It seems that distinct diurnal changes of arousal indicate emotional lability and may be associated with emotional responsiveness, which in turn manifests itself in a characteristic style of coping with stressful situations. One may therefore consider the diurnal variability of arousal as a factor increasing individual susceptibility to mood swings and affective disorders.

I Don't Want to Miss a Thing - Learning Dynamics and Effects of Feedback Type and Monetary Incentive in a Paired Associate Deterministic Learning Task.

Effective functioning in a complex environment requires adjusting of behavior according to changing situational demands. To do so, organisms must learn new, more adaptive behaviors by extracting the necessary information from externally provided feedback. Not surprisingly, feedback-guided learning has been extensively studied using multiple research paradigms. The purpose of the present study was to test the newly designed Paired Associate Deterministic Learning task (PADL), in which participants were presented with either positive or negative deterministic feedback. Moreover, we manipulated the level of motivation in the learning process by comparing blocks with strictly cognitive, informative feedback to blocks where participants were additionally motivated by anticipated monetary reward or loss. Our results proved the PADL to be a useful tool not only for studying the learning process in a deterministic environment, but also, due to the varying task conditions, for assessing differences in learning patterns. Particularly, we show that the learning process itself is influenced by manipulating both the type of feedback information and the motivational significance associated with the expected monetary reward.

Cognitive Impairments in Occupational Burnout - Error Processing and Its Indices of Reactive and Proactive Control.

The presented study refers to cognitive aspects of burnout as the effects of long-term work-related stress. The purpose of the study was to investigate electrophysiological correlates of burnout to explain the mechanisms of the core burnout symptoms: exhaustion and depersonalization/cynicism. The analyzed error-related electrophysiological markers shed light on impaired cognitive mechanisms and the specific changes in information-processing in burnout. In the EEG study design (N = 80), two components of error-related potential (ERP), error-related negativity (ERN), and error positivity (Pe), were analyzed. In the non-clinical burnout group (N = 40), a significant increase in ERN amplitude and a decrease in Pe amplitude were observed compared to controls (N = 40). Enhanced error detection, indexed by increased ERN amplitude, and diminished response monitoring, indexed by decreased Pe amplitude, reveal emerging cognitive problems in the non-clinical burnout group. Cognitive impairments in burnout subjects relate to both reactive and unconscious (ERN) and proactive and conscious (Pe) aspects of error processing. The results indicate a stronger 'reactive control mode' that can deplete resources for proactive control and the ability to actively maintain goals. The analysis refers to error processing and specific task demands, thus should not be extended to cognitive processes in general. The characteristics of ERP patterns in burnout resemble psychophysiological indexes of anxiety (increased ERN) and depressive symptoms (decreased Pe), showing to some extent an overlapping effect of burnout and related symptoms and disorders. The results support the scarce existing data on the psychobiological nature of burnout, while extending and specifying its cognitive characteristics.

Neurophysiological Markers of Emotion Processing in Burnout Syndrome.

The substantial body of research employing subjective measures indicates that burnout syndrome is associated with cognitive and emotional dysfunctions. The growing amount of neurophysiological and neuroimaging research helps in broadening existing knowledge of the neural mechanisms underlying core burnout components (emotional exhaustion and depersonalization/cynicism) that are inextricably associated with emotional processing. In the presented EEG study, a group of 93 participants (55 women; mean age = 35.8) were selected for the burnout group or the demographically matched control group on the basis of the results of the Maslach Burnout Inventory - General Survey (MBI-GS) and the Areas of Worklife Survey (AWS). Subjects then participated in an EEG experiment using two experimental procedures: a facial recognition task and viewing of passive pictures. The study focuses on analyzing event-related potentials (ERPs): N170, VPP, EPN, and LPP, as indicators of emotional information processing. Our results show that burnout subjects, as compared to the control group, demonstrate significantly weaker response to affect-evoking stimuli, indexed by a decline in VPP amplitude to emotional faces and decreased EPN amplitude in processing emotional scenes. The analysis of N170 and LPP showed no significant between-group difference. The correlation analyses revealed that VPP and EPN, which are ERP components related to emotional processing, are associated with two core burnout symptoms: emotional exhaustion and cynicism. To our knowledge, we are one of the first research groups to use ERPs to demonstrate such a relationship between neurophysiological activity and burnout syndrome in the context of emotional processing. Thus, in conclusion we emphasized that the decreased amplitude of VPP and EPN components in the burnout group may be a neurophysiological manifestation of emotional blunting and may be considered as neurophysiological markers of emotional exhaustion and cynicism. Additionally, we did not observe a decrease in LPP, which may be considered as a marker that significantly differentiates burnout from depression.

Preliminary analyses of psychometric characteristics of the Polish version of the Obsessive-Compulsive Inventory-Revised (OCI-R) in a non-clinical sample.

OBJECTIVES: Obsessive-compulsive disorder (OCD) is an anxiety-spectrum disorder that affects 1-2% of the adult population. People with OCD are more likely to report impaired social and occupational functioning. Although effective treatments of the OCD exist, many sufferers from this disorder are continuously misdiagnosed. Therefore, improving the assessment of the OCD remains an important area of scientific research. The main goal of the study is the initial verification of psychometric properties in the Polish version of the Obsessive-Compulsive Inventory-Revised (OCI-R) in a college student sample. MATERIAL AND METHODS: A group of students completed a battery of measures consisting of obsessive-compulsive symptoms (The OCI-R, The Yale-Brown Obsessive Compulsive Scale), depression (The Beck Depression Inventory) and anxiety trait (The State-Trait Anxiety Inventory). RESULTS: A confirmatory factor analysis, conducted on data from 334 university students, supported a solid and replicable 6-fold factor structure of the OCI-R. Further analyses on test-retest reliability (following a 1-month interval), convergent and divergent validity of the OCI-R were respectively conducted in a group of 137 students who had completed a battery of measures mentioned above. The results showed adequate testretest reliability for the full scale and subscales cores, high internal consistency and confirmed satisfactory convergent and divergent validity. CONCLUSIONS: The study constitutes the first phase of work on a Polish version of measurement for obsessive-compulsive symptoms. Satisfactory results obtained in a non-clinical sample allow to recognize this method to be promising for further research. Int J Occup Med Environ Health 2016;29(6):1011-1021.

Job burnout and engagement among teachers - Worklife areas and personality traits as predictors of relationships with work.

INTRODUCTION: The main goal of the present study was to analyze the burnout syndrome due to selected personality traits (based on the Cloninger's psychobiological personality model and positive and negative affectivity) and the degree of mismatch between teachers and their work environment (described in terms of the Model of Worklife Areas). The 2nd goal was to determine if the participants could be classified into different burnout profile groups (clusters) based on their burnout dimension (exhaustion, cynicism and efficacy) scores and whether those groups differed significantly with regard to their personality traits and levels of mismatch between them and the workplace. MATERIAL AND METHODS: Individual and contextual factors responsible for burnout were analyzed in a group of 205 Polish teachers who completed a set of questionnaires: Maslach Burnout Inventory - General Scale, Areas of Worklife Scale, Temperament and Character Inventory, and Positive and Negative Affect Schedule. RESULTS: The hierarchical regression analysis revealed that teachers' efficacy is determined only by personality factors, while exhaustion and cynicism are determined by both individual and organizational variables. The cluster analysis revealed 3 groups (burnout, engaged, ineffective) that varied in the level of all burnout dimensions. Teachers experiencing burnout perceived a higher level of mismatch between themselves and the work environment, compared to the engaged teachers demonstrating better alignment. The engaged teachers were lower on negative affectivity and higher on self-directedness as compared to the burnout group. CONCLUSIONS: The study provided insight into the role of individual factors in the development of teacher burnout and engagement. Negative affectivity could be considered as a predisposing risk factor and self-directedness as a protective factor for burnout.

Measuring individual vulnerability to sleep loss--the CHICa scale.

The aim of this project was to construct a psychometrically satisfying scale to describe subjective reactions to sleep deprivation. First, on the basis of a literature review, a list of items was generated which reflected the negatively affected mood and reduced wellbeing associated with sleep loss. Additionally, psychology students were asked to describe their cognitive and emotional symptoms following a night with curtailed sleep. As a result, 69 items were included in the experimental set. University students (n = 102, females, mean age 22.5 ± 1.9 years) completed the form several times during 1 week in June (while preparing for examinations) and on a free day in September; a total of 460 forms were collected. The final, 26-item version of the scale was validated in a sleep deficit experiment lasting 1 week, conducted with 25 female participants (mean age 23.4 ± 1.9 years). Factor analysis showed 71.7% of total variance explained by four components: impaired thermoregulation (C for cold), disrupted appetite (H for hunger), affective problems (I for irritability) and lowered level of cognitive functioning (Ca for cognitive attenuation). A Polish version of the CHICa scale showed satisfactory psychometric properties. Cronbach's alpha of the subscales were between 0.90 and 0.95. All four subscales exhibited a significant increase with an experimental 3-h daily sleep restriction over a period of 1 week; cognitive attenuation was the most symptomatic. Cognitive problems (reduced concentration, comprehension and accuracy) and a lack of energy seem to be the most specific subjective manifestations of the chronic sleep deficit state. CHICa may be helpful in research on inter-and intra-individual differences and on the efficacy of various counteractive treatments for the consequences of sleep deprivation.

Diurnal patterns of activity of the orienting and executive attention neuronal networks in subjects performing a Stroop-like task: a functional magnetic resonance imaging study.

Attentional processes are fundamental to good cognitive functioning of human operators. The purpose of this study was to analyze the activity of neuronal networks involved in the orienting attention and executive control processes from the perspective of diurnal variability. Twenty-three healthy male volunteers meeting magnetic resonance (MR) inclusion criteria performed the Stroop Color-Word task (block design) in the MR scanner five times/day (06:00, 10:00, 14:00, 18:00, 22:00 h). The first scanning session was scheduled 1-1.5 h after waking. Between MR sessions, subjects performed simulated driving tasks in stable environmental conditions, with controlled physical activity and diet. Significant activation was found in brain regions related to the orienting attentional system: the parietal lobe (BA40) and frontal eye-fields (FEFs). There were also activations in areas of the executive control system: the fronto-insular cortex (FIC), dorsal anterior cingulate cortex (dACC), presupplementary motor area (preSMA), supplementary motor area (SMA), basal ganglia, middle temporal (MT; BA21), and dorsolateral prefrontal cortex (DLPFC), as a part of the central executive network. Significant deactivations were observed in the rostral anterior cingulate cortex (rACC), posterior cingulate cortex (PCC), superior frontal gyrus (SF), parietal lobe (BA39), and parahippocampal that are thought to comprise the default mode network (DMN). Additionally, the activated regions included bilaterally lingual gyrus and fusiform gyrus. The insula was bilaterally deactivated. Visual attention controlled by the goal-oriented attention system and comprising top-down and bottom-up mechanisms, activated by Stroop-like task, turned out to be prone to diurnal changes. The study results show the occurrence of time-of-day-related variations in neural activity of brain regions linked to the orienting attentional system (left parietal lobe-BA40, left and right FEFs), simultaneously providing arguments for temporal stability of the executive system and default mode network. These results also seem to suggest that the involuntary, exogenous (bottom-up) mechanism of attention is more vulnerable to circadian and fatigue factors than the voluntary (top-down) mechanism, which appear to be maintained at the same functional level during the day. The above phenomena were observed at the neural level.

Chronic sleep deficit and performance of a sustained attention task--an electrooculography study.

Electrooculography (EOG) was used to explore performance differences in a sustained attention task during rested wakefulness (RW) and after 7 days of partial sleep deprivation (SD). The RW condition was based on obtaining regular sleep, and the SD condition involved sleep restriction of 3 h/night for a week resulting in a total sleep debt of 21 h. The study used a counterbalanced design with a 2-wk gap between the conditions. Participants performed a sustained attention task for 45 min on four occasions: 10:00-11:00, 14:00-15:00, 18:00-19:00, and 22:00-23:00 h. The task required moving gaze and attention as fast as possible from a fixation point to a target. In each session, 120 congruent and 34 incongruent stimuli were presented, totaling 1232 observations/participant. Correct responses plus errors of omission (lapses) and commission (false responses) were recorded, and the effect of time-of-day on sustained attention following SD was investigated. The analysis of variance (ANOVA) model showed that SD affected performance on a sustained attention task and manifested itself in a higher number of omission errors: congruent stimuli (F((1,64)) = 13.3, p < .001) and incongruent stimuli (F((1,64)) = 14.0, p < .001). Reaction times for saccadic eye movements did not differ significantly between experimental conditions or by time-of-day. Commission errors, however, exhibited a decreasing trend during the day. The visible prevalence of omissions in SD versus RW was observed during the mid-afternoon hours (the so-called post-lunch dip) for both congruent and incongruent stimuli (F((1,16)) = 5.3, p = .04 and F((1,16)) = 5.6, p = .03, respectively), and at 18:00 h for incongruent stimuli (F((1,13)) = 5.7, p = .03).

Chronotype, sleep loss, and diurnal pattern of salivary cortisol in a simulated daylong driving.

The study focused on chronotype-related differences in subjective load assessment, sleepiness, and salivary cortisol pattern in subjects performing daylong simulated driving. Individual differences in work stress appraisal and psychobiological cost of prolonged load seem to be of importance in view of expanding compressed working time schedules. Twenty-one healthy, male volunteers (mean +/- SD: 27.9 +/- 4.9 yrs) were required to stay in semiconstant routine conditions. They performed four sessions (each lasting approximately 2.5 h) of simulated driving, i.e., completed chosen tasks from computer driving games. Saliva samples were collected after each driving session, i.e., at 10:00-11:00, 14:00-15:00, 18:00-19:00, and 22:00-23:00 h as well as 10-30 min after waking (between 05:00 and 06:00 h) and at bedtime (after 00:00 h). Two subgroups of subjects were distinguished on the basis of the Chronotype Questionnaire: morning (M)- and evening (E)-oriented types. Subjective data on sleep need, sleeping time preferences, sleeping problems, and the details of the preceding night were investigated by questionnaire. Subjective measures of task load (NASA Task Load Index [NASA-TLX]), activation (Thayer's Activation-Deactivation Adjective Check List [AD ACL]), and sleepiness (Karolinska Sleepiness Scale [KSS]) were applied at times of saliva samples collection. M- and E-oriented types differed significantly as to their ideal sleep length (6 h 54 min +/- 44 versus 8 h 13 min +/- 50 min), preferred sleep timing (midpoint at 03:19 versus 04:26), and sleep index, i.e., 'real-to-ideal' sleep ratio, before the experimental day (0.88 versus 0.67). Sleep deficit proved to be integrated with eveningness. M and E types exhibited similar diurnal profiles of energy, tiredness, tension, and calmness assessed by AD ACL, but E types estimated higher their workload (NASA-TLX) and sleepiness (KSS). M types exhibited a trend of higher mean cortisol levels than E types (F = 4.192, p < .056) and distinct diurnal variation (F = 2.950, p < .019), whereas E types showed a flattened diurnal curve. Cortisol values did not correlate with subjective assessments of workload, arousal, or sleepiness at any time-of-day. Diurnal cortisol pattern parameters (i.e., morning level, mean level, and range of diurnal changes) showed significant positive correlations with sleep length before the experiment (r = .48, .54, and .53, respectively) and with sleep index (r = .63, .64, and .56, respectively). The conclusions of this study are: (i) E-oriented types showed lower salivary cortisol levels and a flattened diurnal curve in comparison with M types; (ii) sleep loss was associated with lower morning cortisol and mean diurnal level, whereas higher cortisol levels were observed in rested individuals. In the context of stress theory, it may be hypothesized that rested subjects perceived the driving task as a challenge, whereas those with reduced sleep were not challenged, but bored/exhausted with the experimental situation.