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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.

The Necker-Zeno model of bistable perception provides a formal relation between the average duration of meta-stable percepts (dwell times T) of ambiguous figures and two other basic time scales (t(0), ΔT) underlying cognitive processing. The model predicts that dwell times T covary with t(0), ΔT or both. We tested this prediction by exploiting that observers, in particular experienced meditators, can volitionally control dwell times T. Meditators and non-meditators observed bistable Necker cubes either passively or tried to hold their current percept. The latencies of a centro-parietal event-related potential (CPP) were recorded as a physiological correlate of t(0). Dwell times T and the CPP latencies, correlated with t(0), differed between conditions and observer groups, while ΔT remained constant in the range predicted by the model. The covariation of CPP latencies and dwell times, as well as their quadratic functional dependence extends previous psychophysical confirmation of the Necker-Zeno model to psychophysiological measures.

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.

Jeannerod (2001) hypothesized that action execution, imagery, and observation are functionally equivalent. This led to the major prediction that these motor states are based on the same action-specific and even effector-specific motor representations. The present study examined whether hand and foot movements are represented in a somatotopic manner during action execution, imagery, and action observation. The experiment contained ten conditions: three execution conditions, three imagery conditions, three observation conditions, and one baseline condition. In the nine experimental conditions, participants had to execute, observe, or imagine right-hand extension/flexion movements or right-foot extension/flexion movements. The fMRI results showed a somatotopic organization within the contralateral premotor and primary motor cortex during motor imagery and motor execution. However, there was no clear somatotopic organization of action observation in the given regions of interest within the contralateral hemisphere, although observation of these movements activated these areas significantly.

Event-related functional magnetic resonance imaging was applied to identify cortical areas involved in maintaining target information in working memory used for an upcoming grasping action. Participants had to grasp with their thumb and index finger of the dominant right hand three-dimensional objects of different size and orientation. Reaching-to-grasp movements were performed without visual feedback either immediately after object presentation or after a variable delay of 2-12 s. The right inferior parietal cortex demonstrated sustained neural activity throughout the delay, which overlapped with activity observed during encoding of the grasp target. Immediate and delayed grasping activated similar motor-related brain areas and showed no differential activity. The results suggest that the right inferior parietal cortex plays an important functional role in working memory maintenance of grasp-related information. Moreover, our findings confirm the assumption that brain areas engaged in maintaining information are also involved in encoding the same information, and thus extend previous findings on working memory function of the posterior parietal cortex in saccadic behavior to reach-to-grasp movements.

Current models of attention describe attention not as a homogenous entity but as a set of neural networks whose measurement yields a set of three endophenotypes-alerting, orienting, and executive control. Previous findings revealed different neuroanatomical regions for these subsystems, and data from twin studies indicate differences in their heritability. The present study investigated the molecular genetic basis of attention in a sample of 100 healthy subjects. Attention performance was assessed with the attention network test that distinguishes alerting, orienting, and executive control (conflict) using a simple reaction time paradigm with different cues and congruent and incongruent flankers. Two gene loci on candidate genes for cognitive functioning, the functional catechol-O-methyltransferase (COMT) VAL158MET and the tryptophan hydroxylase 2 (TPH2) -703 G/T promoter polymorphism, were tested for possible associations with attention. COMT is involved in the catabolism of dopamine, and TPH is the rate-limiting enzyme for serotonin synthesis. Results showed no effect of the COMT polymorphism on attention performance. However, the TT genotype of TPH2 -03 G/T was significantly associated with more errors (a possible indicator of impaired impulse control; p = .001) and with decreased performance in executive control (p = .001). This single-nucleotide polymorphism on the TPH2 gene explained more than 10% of the variance in both indicators of attention stressing the role of the serotonergic system for cognitive functions.

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.