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While the contingent negative variation (CNV) has been the subject of extensive research over the last fifty years, the maximum duration during which such cortical negativity can be maintained has, to the best of our knowledge, never been systematically explored. Participants were presented with the classic S1-S2 paradigm task, where a warning stimulus (S1) acts as a cue for the appearance of an imperative stimulus (S2). A fast motor response was required upon S2 arrival. Inter-stimulus intervals (ISIs) of 2.5, 5, 7.5 and 10 s duration were presented in blocked fashion. Data was analysed using both EEG referenced to linked mastoids and the current source density (CSD) technique, which maximizes the cortical origin of the measured voltage. Mean late CNV (lCNV) amplitude was found to be significantly higher for fast reaction time (RT) trials when CSD data was split according to the median into 'fast' and 'slow' RT halves. Post-hoc comparisons showed that this RT effect was particularly strong for the 10 s condition. This may be explained by the lack of an lCNV component and thus of cortical negativity prior to S2 in the 10 s condition. Our results suggest that intervals of a duration between 7.5 and 10 s represent the upper boundary during which the lCNV component can be elicited.
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In the general concept of self-disturbances in schizophrenia and schizophrenia spectrum disorders, somatopsychic depersonalization (SPD) occupies a special place as it constitutes a syndrome that comprises feelings of detachment from one's own body and mental processes. However, apart from clinical descriptions, to date the pathophysiology of SPD is not fully understood due to the rareness of the syndrome and a lack of experimental studies. In a case study of one patient with schizotypal disorder, we applied a multimodal approach to understanding the SPD phenomena. The patient's clinical profile was identified as disruption of implicit bodily function, accompanied by depressive symptoms. On a neuropsychological level, the patient exhibited impairment in executive functioning, intact tactile perception and kinesthetic praxis. Behavioral tests revealed an altered sense of time but unimpaired self-agency. Furthermore, the patient exhibited a lack of empathy and he had autistic traits, although with a sufficient ability to verbalize his feelings. On the neurobiological level using an active and passive touch paradigm during functional magnetic resonance imaging (fMRI), we found a hyperconnectivity of the default-mode network and salience network and a hypoconnectivity of the central executive brain networks in the performance of the touch task as well as intact perceptual touch processing emerging from the direct comparisons of the touch conditions. Our data provide evidence for the important role of altered large-brain network functioning in SPD that corresponds to the specific behavioral and neurocognitive phenomena.
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OBJECTIVES: The study aimed to clarify whether cognitive and psychomotor performance, which are important for occupational and traffic safety, are impaired by working permanent night shifts (NSs) compared with early-late two shifts (TSs) and whether age and chronobiological type influences the relationship between shift and performance. METHODS: The study included 44 male automobile workers, 20 working TSs and 24 working NSs. Chronobiological type was determined by questionnaire (D-MEQ). Each subject was tested at the beginning and end of the shift for alertness [by a visual analogue scale (VAS)]; feeling of well-being (Basler); concentration and accuracy (d2); reaction speed, orientation and reaction to stress (Vienna System). RESULTS: TS workers were more frequently morning types whereas the NS workers were more frequently evening types. In the performance tests, the TS and NS workers did not differ at shift start or shift end. Over the course of the shift, concentration and accuracy improved in both groups, as did reaction to stress. Chronobiological type alone or in combination with shift type had no effect on performance. CONCLUSIONS: The results of this study indicate that-if chosen voluntarily-working NSs has no immediate negative effects on cognitive and psychomotor performance when compared with working TSs. There was no indication of an increased risk of accidents after working NSs. The unequal distribution of the circadian types in the shift groups may indicate selection.
Erkunden
Team
Eintragsart
Sprache
- Englisch (3)
Thema
- Psychomotor Performance/*physiology
- Adolescent (1)
- Adult (3)
- Attention/physiology (1)
- Brain/physiopathology (1)
- Cerebral Cortex/*physiology (1)
- Circadian Rhythm/physiology (1)
- Cognition/*physiology (1)
- Contingent negative variation (1)
- Contingent Negative Variation/*physiology (1)
- Current source density (1)
- Depersonalization/*complications (1)
- disembodiment (1)
- Electroencephalography/*methods (1)
- Event-related potential (1)
- Fatigue (1)
- Female (1)
- fMRI (1)
- Humans (3)
- Industry (1)
- Magnetic Resonance Imaging (1)
- Male (3)
- Middle Aged (1)
- neurocognition (1)
- Neuropsychological Tests (1)
- Pain Measurement (1)
- Reaction time (1)
- Reaction Time/*physiology (1)
- Reaction Time/physiology (1)
- Safety (1)
- schizotypal disorder (1)
- Schizotypal Personality Disorder/*complications/physiopathology (1)
- self (1)
- Slow cortical potential (1)
- Somatoform Disorders/complications (1)
- somatopsychic depersonalization (1)
- Time Factors (1)
- time perception (1)
- touch (1)
- Work Schedule Tolerance/*physiology/*psychology (1)
- Young Adult (1)