Krystyna Golonka

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. (Author correspondence: marek@uj.edu.pl)

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 ∼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 (Thayers 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. (Author correspondence: mmoginsk@cyf-kr.edu.pl)

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). (Author correspondence: magda.fafrowicz@uj.edu.pl)

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.

Diurnal variability of human operator attention disengagement and chronotype: an fMRI-based case study

The main objective of this study was to analyse diurnal variations during attention disengagement operations on a neuronal level in a group of subjects representing extreme chronotypes. The parietal lobes of the participants were scanned four times per day for activity changes using functional magnetic resonance imaging (fMRI), while the subjects performed the task at hand. The findings provide credible evidence of the existence of variability in the activity patterns and levels of the parietal lobes. The activity patterns and levels depend on both the participants’ chronotype as well as time of day. The morning type showed stronger activation of the left parietal lobe, while the evening type showed stronger activation of the right parietal lobe. There was a visible decrease in parietal lobe activity during the post-lunch dip, independent of the subjects’ chronotype. Such variability of parietal lobe activity may suggest that humans are more likely to make errors during task performance at certain times of the day as opposed to others.

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.

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.