A test-retest reliability analysis of diffusion measures of white matter tracts relevant for cognitive control

Recent efforts to replicate structural brain-behavior correlations have called into question the replicability of structural brain measures used in cognitive neuroscience. Here, we report an evaluation of test-retest reliability of diffusion tensor imaging (DTI) measures, including fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity, in several white matter tracts previously shown to be involved in cognitive control. In a data set consisting of 34 healthy participants scanned twice on a single day, we observe overall stability of DTI measures. This stability remained in a subset of participants who were also scanned a third time on the same day as well as in a 2-week follow-up session. We conclude that DTI measures in these tracts show relative stability, and that alternative explanations for the recent failures of replication must be considered

A perspective on terra incognita: uncovering the neuroanatomy of the human subcortex

Recent exciting advancements in the field of in vivo neuroimaging allow for visualization of the living human brain with unprecedented anatomical detail. Large consortium studies will provide us with novel insights in the function and connectivity of the human brain. However, it is unlikely that the spatial resolution obtained using in vivo imaging will, in the near future, approximate the level of detail obtained in post-mortem anatomical studies. Initiatives such as the recently published Big Brain project (Amunts et al., 2013) herald a novel approach in post-mortem brain research. We feel that linking data from histological observations with in vivo imaging studies will greatly advance our understanding of the functional neuroanatomy of the human brain

Are there three subdivisions in the primate subthalamic nucleus?

The prevailing academic opinion holds that the subthalamic nucleus (STN) consists of three parts, each anatomically distinct and selectively associated with cognitive, emotional, or motor functioning. We independently tested this assumption by summarizing the results from 33 studies on STN subdivisions in human and nonhuman primates. The studies were conducted from 1925 to 2010 and feature three different techniques: electrical lesions, anterograde and retrograde tracers, and classical cytoarchitectonics. Our results reveal scant evidence in support of a tripartite STN. Instead, our results show that the variability across studies is surprisingly large, both in the number of subdivisions and in their anatomical localization. We conclude that the number of subdivisions in the STN remains uncertain, and that academic consensus in support of a tripartite STN is presently unwarranted

Hell and the image of God: an examination of Herman Bavinck's and Jürgen Moltmann's views on hell and the image of God and what these perceptions have to contribute when discussing hell in the 21st century

Masterthesis Intercultural Reformed Theolog

Impact of ethanol containing gasoline blends on emissions from a flex-fuel vehicle tested over the Worldwide Harmonized Light duty Test Cycle (WLTC)

AbstractRegulated and unregulated emissions from a Euro 5a flex-fuel vehicle tested with nine different hydrous and anhydrous ethanol containing fuel blends at 23 and −7°C over the World harmonized Light-duty vehicle Test Cycle and the New European Driving Cycle, were investigated at the Vehicle Emission Laboratory at the European Commission Joint Research Centre Ispra, Italy. The experimental results showed no differences on the regulated and unregulated emissions when hydrous ethanol blends were used instead of anhydrous ethanol blends. The use of E85 and E75 blends (gasoline containing 85% and 75% of ethanol, respectively) resulted in a reduction of NOx emissions (30–55%) but increased the emissions of carbon monoxide, methane, carbonyls and ethanol compared to E5, E10 and E15 blends (gasoline containing 5%, 10% and 15% of ethanol, respectively). The increase of the acetaldehyde and ethanol emissions (up to 120% and 350% at 23°C and up to 400% and 390% at −7°C, for acetaldehyde and ethanol, respectively) caused a severe increment of the ozone formation potential. Most of the studied pollutants presented similar emission factors during the tests performed with E10 and E15 blends. The emission factors of most unregulated compounds were lower over the NEDC (with ammonia as an exception) than over the WLTC. However, when taking into consideration only the cold start emissions, emission factors over the WLTC were observed to be higher, or similar, to those obtained over the NEDC. Low ambient temperature caused an increase of the emissions of all studied compounds with all tested blends

Age-related normal limits for spatial vision: Separating the effects of normal ageing from changes caused by disease

The primary aim of this study was to establish age-related, normal limits of monocular and binocular spatial vision under photopic and high mesopic conditions. Photopic and mesopic Visual Acuity (VA) and Functional Contrast Sensitivity (FCS) were measured with both positive and negative contrast optotypes under both binocular and monocular viewing conditions using the Acuity-Plus (AP) test. The experiments were carried out in normally sighted participants, aged 10 to 86 years. Data from participants who failed to meet pre-defined normal sight criteria were not included in the analysis. Mean and ±2.5σ were calculated for participants within 5-year subgroups. A biologically meaningful model was then fitted to these data. The Gauss-Newton method was used to calculate optimum, best-fit model parameters to predict mean values and upper and lower threshold limits for VA and FCS. These limits describe the effects of normal ageing on spatial vision for each of the 16 experimental conditions investigated. Out of the 382 participants recruited for this study, 285 participants passed the selection criteria for normal aging. Log transforms were applied to ensure approximate normal distributions. Outliers were also removed for each of the 16 stimulus conditions investigated based on the ±2.5σ limits criterion. The results show that under photopic conditions, the overall variability in results for both VA and FCS remained age-invariant up to ~50 years. A lower, age-invariant limit of ~ 30 years was more appropriate for the mesopic range with a gradual, but accelerating increase in both mean thresholds and inter-subject variability above this age. Binocular thresholds were smaller and much less variable when compared to either eye. This study has established upper normal, age limits for monocular and binocular viewing under photopic and high mesopic lighting conditions with both positive and negative contrast optotypes using a single test which can be implemented either in the clinic or in an occupational setting. Measurements of participants excluded from analysis due to systemic and/or ocular conditions were analysed separately and plotted against the newly established age-related normal limits of spatial vision in both lighting conditions. A substantial number of those excluded failed to meet the age-related normal limits established in the study. These preliminary findings suggest that the new age-related normal limits may turn out to be very useful in screening for systemic and ocular conditions in clinical practice