Components of acquisition-to-acquisition variance in continuous arterial spin labelling (CASL) imaging

<p>Abstract</p> <p>Background</p> <p>Images of perfusion estimates obtained with the continuous arterial spin labelling technique are characterized by variation between single acquisitions. Little is known about the spatial determinants of this variation during the acquisition process and their impact on voxel-by-voxel estimates of effects.</p> <p>Results</p> <p>We show here that the spatial patterns of covariance between voxels arising during the acquisition of these images uncover distinct mechanisms through which this variance arises: through variation in global perfusion levels; through the action of large vessels and other, less well characterized, large anatomical structures; and through the effect of noisy areas such as the edges of the brain.</p> <p>Conclusions</p> <p>Knowledge of these covariance patterns is important to experimenters for a correct interpretation of findings, especially for studies where relatively few acquisitions are made.</p

Task-Dependent Individual Differences in Prefrontal Connectivity

Recent advances in neuroimaging have permitted testing of hypotheses regarding the neural bases of individual differences, but this burgeoning literature has been characterized by inconsistent results. To test the hypothesis that differences in task demands could contribute to between-study variability in brain-behavior relationships, we had participants perform 2 tasks that varied in the extent of cognitive involvement. We examined connectivity between brain regions during a low-demand vigilance task and a higher-demand digit–symbol visual search task using Granger causality analysis (GCA). Our results showed 1) Significant differences in numbers of frontoparietal connections between low- and high-demand tasks 2) that GCA can detect activity changes that correspond with task-demand changes, and 3) faster participants showed more vigilance-related activity than slower participants, but less visual-search activity. These results suggest that relatively low-demand cognitive performance depends on spontaneous bidirectionally fluctuating network activity, whereas high-demand performance depends on a limited, unidirectional network. The nature of brain-behavior relationships may vary depending on the extent of cognitive demand. High-demand network activity may reflect the extent to which individuals require top-down executive guidance of behavior for successful task performance. Low-demand network activity may reflect task- and performance monitoring that minimizes executive requirements for guidance of behavior

The prevalence of effort-reward imbalance and its associations with working conditions, psychosocial resources and burden among health care workers during the COVID-19 pandemic: Results of the egePan-Voice study

ObjectiveThe association between a measure of effort-reward imbalance (ERI) and profession as well as gender in a sample of health care workers (HCW) during the first wave of the COVID-19 pandemic in Germany using the egePan-Voice study. In addition, we examined, which factors are associated with an effort-reward imbalance ratio (ERI ratio) &gt;1.MethodsIn a large sample of HCW (N = 6174) we assessed occupational stress with the short version of the effort-reward imbalance (ERI) questionnaire, working conditions, COVID-19-related problems and psychosocial resources (ENRICHD Social Support Inventory, ESSI; Sense of Coherence Scale, SOC-3 and optimism, SOP2).ResultsThe prevalence of a ERI ratio &gt;1 among HCW was 50.9%. The prevalence’s of an ERI ratio &gt;1 were statistically significant different between gender as well as the occupational profession. The proportion of women (51.8%) with ERI ratio &gt;1 was significantly higher than among men (47.8%). The highest ERI imbalance was found among nurses (62.8%), followed by medical technical assistants (MTA) (58.8%), while psychologists/psychotherapists revealed the lowest value (37.8%), followed by physicians (41.8%). In the total sample, most essential factors reported at this time for increased ERI ratio were: insufficient staff for the current work load, insufficient recovery, feeling insufficiently protected by measures taken by the hospital/the employer, high occupancy rate of the wards, insufficient trust in colleagues and being a nurse as compared with being a physician.ConclusionThe findings indicate a high proportion of HCW with effort-reward imbalance and substantial profession-related differences. Preventive interventions should be offered to vulnerable groups among the HCW to decrease the imbalance measured by work stress.</jats:sec

The neural substrate of positive bias in spontaneous emotional processing

Even in the presence of negative information, healthy human beings display an optimistic tendency when thinking of past success and future chances, giving a positive bias to everyday's cognition. The tendency to actively select positive thoughts suggests the existence of a mechanism to exclude negative content, raising the issue of its dependence on mechanisms like those of effortful control. Using perfusion imaging, we examined how brain activations differed according to whether participants were left to prefer positive thoughts spontaneously, or followed an explicit instruction to the same effect, finding a widespread dissociation of brain perfusion patterns. Under spontaneous processing of emotional material, recruitment of areas associated with effortful attention, such as the dorsolateral prefrontal cortex, was reduced relative to instructed avoidance of negative material (F(1,58) = 26.24, p = 0.047, corrected). Under spontaneous avoidance perfusion increments were observed in several areas that were deactivated by the task, including the perigenual medial prefrontal cortex. Furthermore, individual differences in executive capacity were not associated with positive bias. These findings suggest that spontaneous positive cognitive emotion regulation in health may result from processes that, while actively suppressing emotionally salient information, differ from those associated with effortful and directed control

Health Care Provider Knowledge of the Immunization Schedule and the Contraindications to Vaccinate

The purpose to this study was to determine if the current knowledge of Kent county\u27s health care providers contributed to the under immunization of children less than two years of age. A survey, modified from a previous study done in Los Angeles, was distributed to Family Practice and Pediatrics offices within the greater Grand Rapids area. Several areas of health care provider knowledge were assessed. These included: (1) knowledge of the primary series immunization schedule in both a child on time and delinquent, (2) knowledge of timing between diptheria, tetanus, and pertussis boosters, and (3) knowledge of the contraindications to vaccinate. The results showed an 89% correct response rate for knowledge of the immunization schedule and an 80% correct response rate for knowledge of the contraindications to vaccinate. Overall it was concluded that Kent county health care providers were sufficiently knowledgeable in both areas stated and, therefore, did not significantly contribute to the under immunization of young children

Combined modes of gradual change: the case of academic upgrading and declining collectivism in German skill formation

The corporatist-governed dual-training system has been a key example of collective governance in the German capitalist model. However, high-end dual-training is increasingly being offered within post-secondary higher education. Here, firms and universities, not chambers of commerce or trade unions, are the actors negotiating the curricula of and access to a range of ‘dual-study programmes’. This article traces the emergence and expansion of this more firm-specific skills provision system, which diminishes the beneficial constraints for strategic cooperation and, in turn, the provision of collective training standards and transferable skills. The case study builds on the ‘gradual institutional change’ taxonomy, while pointing to the potential benefits of using different modes of change in combination. Through analysing firms’ strategies to initiate change in an institutional grey area between established socio-economic spheres, the article shows how layering, conversion and drift can become interlinked and how each individual process can trigger and feed the next. (DIPF/Orig.

Die Bedeutung fehlerhafter Antworten auf die Fehlerverarbeitung bei Patienten mit einer schweren Depression: eine Studie mit ereigniskorrelierten Potentialen

Wir analysierten Fehlerverarbeitungsprozesse bei Patienten mit "Major Depression" und einer gesunden Kontrollgruppe. Alle Probanden wurden mit Hilfe einer modifizierten Go/Nogo Aufgabe untersucht, während der ein 64-Kanal Elektroenzephalogramm abgeleitet wurde. Von besonderem Interesse war der Einfluss von negativer Rückmeldung im vorhergehenden Durchgang auf den aktuellen Durchgang . Folglich untersuchten wir vier verschiedene Bedingungen: fehlerhafter Durchgang nach fehlerhaftem Durchgang (EE), korrekter Durchgang nach fehlerhaftem Durchgang (EC), fehlerhafter Durchgang nach korrektem Durchgang (CE) und korrekter Durchgang nach korrektem Durchgang (CC). Untersuchungen mit Brain Elektric Source Analysis und funktionelle Magnet-Resonanz-Tomographie Studien konnten zeigen, dass die ERN/Ne (Error related negativity/ Error negativity) Komponenten im Bereich des anterioren cingulären Kortex und präfrontalen Kortex generiert werden. Insbesondere PET-Studien wiesen bei depressiven Patienten eine Hypoaktivität in diesen Hirnregionen nach, so dass eine Veränderung der ERN/Ne Komponenten bei "Major Depression" durchaus plausibel ist. Vorhersagegemäß fand sich in der Patientengruppe eine flachere Feedback relatierte ERN/Ne für Bedingung EE. Hinsichtlich der anderen Bedingungen, Reaktionszeiten und Fehlerraten fanden sich keine signifikanten Gruppenunterschiede. Das vorliegende Ergebnis lässt auf Schwierigkeiten Depressiver bei der Bewertung negativer Rückmeldungen schließen. Die verminderte Amplitude der fERN/Ne spiegelt die abnormale Reaktion Depressiver auf ein negatives Feedback wider. Die vorliegende Arbeit konnte zudem aufzeigen, dass flachere fERN/Ne Amplituden sich sowohl für "errors of choice" als auch für "errors of commission" finden lassen

Auditory risk assessment of college music students in jazz band-based instructional activity

It is well-known that musicians are at risk for music-induced hearing loss, however, systematic evaluation of music exposure and its effects on the auditory system are still difficult to assess. The purpose of the study was to determine if college students in jazz band-based instructional activity are exposed to loud classroom noise and consequently exhibit acute but significant changes in basic auditory measures compared to non-music students in regular classroom sessions. For this we (1) measured and compared personal exposure levels of college students (n = 14) participating in a routine 50 min jazz ensemble-based instructional activity (experimental) to personal exposure levels of non-music students (n = 11) participating in a 50-min regular classroom activity (control), and (2) measured and compared pre- to post-auditory changes associated with these two types of classroom exposures. Results showed that the L eq (equivalent continuous noise level) generated during the 50 min jazz ensemble-based instructional activity ranged from 95 dBA to 105.8 dBA with a mean of 99.5 ± 2.5 dBA. In the regular classroom, the L eq ranged from 46.4 dBA to 67.4 dBA with a mean of 49.9 ± 10.6 dBA. Additionally, significant differences were observed in pre to post-auditory measures between the two groups. The experimental group showed a significant temporary threshold shift bilaterally at 4000 Hz (P < 0.05), and a significant decrease in the amplitude of transient-evoked otoacoustic emission response in both ears (P < 0.05) after exposure to the jazz ensemble-based instructional activity. No significant changes were found in the control group between pre- and post-exposure measures. This study quantified the noise exposure in jazz band-based practice sessions and its effects on basic auditory measures. Temporary, yet significant, auditory changes seen in music students place them at risk for hearing loss compared to their non-music cohorts