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

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

Results of a factor analysis of items regarding COVID-19 pandemic-specific workload among medical staff in Germany

INTRODUCTION: Epidemics lead to an increase in occupational stress and psychological strain among medical staff (cf. Mulfinger et al. 2020). However, there are no validated questionnaires to measure stress caused by an epidemic such as Covid-19, instead self-constructed questions are used frequently. OBJECTIVES: The aim was to develop items for the assessment of specific workload in epidemics which can be used to obtain longitudinal data. METHODS: A sample of N=8078 persons working in the health care sector in Germany participated in the VOICE, EviPan online survey addressing the burden of Covid-19 pandemic during the 2nd quarter of 2020. We used 15 self-constructed items to examine whether these items can represent Covid-19 specific topics. A total of N=7549 (24% males) had complete data to run a confirmatory factor analysis using SEM procedure in Stata 14.2. RESULTS: Five factors were identified a priory: Factor (F) 1: Workload due to Covid-19 pandemic (4 items; Cronbachs’ alpha (α))=0.740); F 2: Fear, uncertainty of SarsCoV-2infection (self and others) (3 items; α= 0.741); F 3: Patient safety (3 items; α=0.533; F 4: Perception of protection concepts (2 items; α=0.590); F 5: Dysfunctional coping strategies (3 items; α=0.447). Fit-Indices: χ²(73)= 1373.849, p<.001, CFI=.946, TLI=.923, RMSEA=.0049, SRMR=.037) CONCLUSIONS: We identified 5 factors associated with problems occurring during the Covid-19 pandemic with acceptable to good internal consistency. Most of the constructed items could therefore be used in further surveys to monitor stress, as a basis for recommendations in the area of stress prevention and interventions for medical staff during epidemics

Oral submucosal dendrocytes: factor XIIIa+ and CD34+ dendritic cell populations in normal tissue and fibrovascular lesions

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71875/1/j.1600-0560.1992.tb00612.x.pd