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Chapter 26: the temporal dynamics of emotional responding: implications for well-being and health from the MIDUS
In this chapter findings are reviewed from the MIDUS Neuroscience Project that underscore the value in examining the temporal dynamics of responses to brief emotional provocation for understanding linkages among emotions and factors contributing to health and well-being across the MIDUS study. This rich dataset has allowed the exploration of associations between individual differences in the affective chronometry of negative and positive emotional responses in vulnerable vs. resilient profiles. Findings from functional magnetic resonance imaging (fMRI) as well as electromyographic recordings (EMG) of the facial muscles to objectively measure emotional responses demonstrate that the temporal dynamics of emotional responses to affective stimuli are associated with aging, personality, psychopathology, stress exposure, biomarkers, and well-being. Overall, these findings suggest that variation in health and well-being are differentially predicted by specific temporal parameters of the emotional response, such as the magnitude of the immediate response to the presence of a stimulus (i.e., reactivity), residual activity and its duration after stimulus offset (i.e., recovery), as well as the change in response – or habituation - across repeated presentations of similarly-valenced stimuli. Besides the seemingly obvious import of recovering quickly from negative or unpleasant provocations, the chronometry of positive emotional responses appears to be particularly vital for determining how emotional processes may take a physiological toll or promote resiliency in the face of stress and disease. By examining such temporal dynamics in response to affective stimuli in MIDUS, a better understanding of the brain-behavior associations underlying emotion, and how emotions “get under the skin” to impact well-being and health across the lifespan is gained
Redshift Filtering by Swift Apparent X-ray Column Density
We remark on the utility of an observational relation between the absorption
column density in excess of the Galactic absorption column density, , and redshift, z, determined from
all 55 Swift-observed long bursts with spectroscopic redshifts as of 2006
December. The absorption column densities, , are determined
from powerlaw fits to the X-ray spectra with the absorption column density left
as a free parameter. We find that higher excess absorption column densities
with cm are only present in bursts
with redshifts z2. Low absorption column densities with cm appear preferentially in high-redshift bursts. Our
interpretation is that this relation between redshift and excess column density
is an observational effect resulting from the shift of the source rest-frame
energy range below 1 keV out of the XRT observable energy range for high
redshift bursts. We found a clear anti-correlation between
and z that can be used to estimate the range of the maximum redshift of an
afterglow. A critical application of our finding is that rapid X-ray
observations can be used to optimize the instrumentation used for ground-based
optical/NIR follow-up observations. Ground-based spectroscopic redshift
measurements of as many bursts as possible are crucial for GRB science.Comment: revised version including updates and the referee's comments,
accepted for publication in the Astronomical Journal, 12 pages, 2 figures, 2
tables - v3 contains an update on the reference lis
Swift and XMM-Newton Observations of the Extraordinary GRB 060729: An afterglow with a more than 100 days X-ray light curve
We report the results of the Swift and XMM observations of the
Swift-discovered long Gamma-Ray Burst GRB 060729 (=115s). The afterglow
of this burst was exceptionally bright in X-rays as well as at UV/Optical
wavelengths showing an unusually long slow decay phase (=0.14\plm0.02)
suggesting a larger energy injection phase at early times than in other bursts.
The X-ray light curve displays a break at about 60 ks after the burst. The
X-ray decay slope after the break is =1.29\plm0.03. Up to 125 days
after the burst we do not detect a jet break, suggesting that the jet opening
angle is larger than 28 degrees. In the first 2 minutes after the burst (rest
frame) the X-ray spectrum of the burst changed dramatically from a hard X-ray
spectrum to a very soft one. We find that the X-ray spectra at this early phase
can all be fitted by an absorbed single power law model or alternatively by a
blackbody plus power law model. The power law fits show that the X-ray spectrum
becomes steeper while the absorption column density decreases. In Swift's
UV/Optical telescope the afterglow was clearly detected up to 9 days after the
burst in all 6 filters and even longer in some of the UV filters with the
latest detection in the UVW1 31 days after the burst. A break at about 50 ks is
clearly detected in all 6 UVOT filters from a shallow decay slope of about 0.3
and a steeper decay slope of 1.3. In addition to the \swift observations we
also present and discuss the results from a 61 ks ToO observation by XMM.
(Abriviated)Comment: Accepted to be published in the Astrophysical Journal, 28 pages, 10
figure
Discerning the physical origins of cosmological Gamma-ray bursts based on multiple observational criteria: the cases of z=6.7 GRB 080913, z=8.3 GRB 090423, and some short/hard GRBs
(Abridged) The two high-redshift gamma-ray bursts, GRB 080913 at z=6.7 and
GRB 090423 at z=8.3, recently detected by Swift appear as intrinsically short,
hard GRBs. They could have been recognized by BATSE as short/hard GRBs should
they have occurred at z <= 1. We perform a more thorough investigation on two
physically distinct types (Type I/II) of cosmological GRBs and their
observational characteristics. We reiterate the definitions of Type I/II GRBs
and review the observational criteria and their physical motivations. Contrary
to the traditional approach of assigning the physical category based on the
gamma-ray properties (duration, hardness, and spectral lag), we take an
alternative approach to define the Type I and Type II Gold Samples using
several criteria that are more directly related to the GRB progenitors, and
study the properties of the two Gold Samples and compare them with the
traditional long/soft and short/hard samples. We find that the Type II Gold
Sample reasonably tracks the long/soft population, although it includes several
intrinsically short (shorter than 1s in the rest frame) GRBs. The Type I Gold
Sample only has 5 GRBs, 4 of which are not strictly short but have extended
emission. Other short/hard GRBs detected in the Swift era represent the BATSE
short/hard sample well, but it is unclear whether all of them belong to Type I.
We suggest that some (probably even most) high-luminosity short/hard GRBs
instead belong to Type II. We suggest that GRB 080913 and GRB 090423 are more
likely Type II events. We re-emphasize the importance of invoking multiple
observational criteria, and cautiously propose an operational procedure to
infer the physical origin of a given GRB with available multiple observational
criteria, with various caveats laid out.Comment: 32 pages, ApJ, in press. The strengths and weaknesses of physical
classification and its relation to phenomenological classification are fully
discussed in a newly added section 3. Discussions on GRBs 090423, 090426, and
090510 are include
Very Early Optical Afterglows of Gamma-Ray Bursts: Evidence for Relative Paucity of Detection
Very early observations with the Swift satellite of gamma-ray burst (GRB)
afterglows reveal that the optical component is not detected in a large number
of cases. This is in contrast to the bright optical flashes previously
discovered in some GRBs (e.g. GRB 990123 and GRB 021211). Comparisons of the
X-ray afterglow flux to the optical afterglow flux and prompt gamma-ray fluence
is used to quantify the seemingly deficient optical, and in some cases X-ray,
light at these early epochs. This comparison reveals that some of these bursts
appear to have higher than normal gamma-ray efficiencies. We discuss possible
mechanisms and their feasibility for explaining the apparent lack of early
optical emission. The mechanisms considered include: foreground extinction,
circumburst absorption, Ly-alpha blanketing and absorption due to high
redshift, low density environments, rapid temporal decay, and intrinsic
weakness of the reverse shock. Of these, foreground extinction, circumburst
absorption, and high redshift provide the best explanations for most of the
non-detections in our sample. There is tentative evidence of suppression of the
strong reverse shock emission. This could be because of a
Poynting-flux-dominated flow or a pure non-relativistic hydrodynamical reverse
shock.Comment: 22 pages, 5 figures. Accepted for publication in Ap
Neuroimaging-Based Classification of PTSD Using Data-Driven Computational Approaches:A Multisite Big Data Study from the ENIGMA-PGC PTSD Consortium
BACKGROUND: Recent advances in data-driven computational approaches have been helpful in devising tools to objectively diagnose psychiatric disorders. However, current machine learning studies limited to small homogeneous samples, different methodologies, and different imaging collection protocols, limit the ability to directly compare and generalize their results. Here we aimed to classify individuals with PTSD versus controls and assess the generalizability using a large heterogeneous brain datasets from the ENIGMA-PGC PTSD Working group.METHODS: We analyzed brain MRI data from 3,477 structural-MRI; 2,495 resting state-fMRI; and 1,952 diffusion-MRI. First, we identified the brain features that best distinguish individuals with PTSD from controls using traditional machine learning methods. Second, we assessed the utility of the denoising variational autoencoder (DVAE) and evaluated its classification performance. Third, we assessed the generalizability and reproducibility of both models using leave-one-site-out cross-validation procedure for each modality.RESULTS: We found lower performance in classifying PTSD vs. controls with data from over 20 sites (60% test AUC for s-MRI, 59% for rs-fMRI and 56% for d-MRI), as compared to other studies run on single-site data. The performance increased when classifying PTSD from HC without trauma history in each modality (75% AUC). The classification performance remained intact when applying the DVAE framework, which reduced the number of features. Finally, we found that the DVAE framework achieved better generalization to unseen datasets compared with the traditional machine learning frameworks, albeit performance was slightly above chance.CONCLUSION: These results have the potential to provide a baseline classification performance for PTSD when using large scale neuroimaging datasets. Our findings show that the control group used can heavily affect classification performance. The DVAE framework provided better generalizability for the multi-site data. This may be more significant in clinical practice since the neuroimaging-based diagnostic DVAE classification models are much less site-specific, rendering them more generalizable.</p
Effects of long-term exposure to an electronic containment system on the behaviour and welfare of domestic cats
Free-roaming cats are exposed to a variety of risks, including involvement in road traffic accidents. One way of mitigating these risks is to contain cats, for example using an electronic boundary fence system that delivers an electric ‘correction’ via a collar if a cat ignores a warning cue and attempts to cross the boundary. However, concerns have been expressed over the welfare impact of such systems. Our aim was to determine if long-term exposure to an electronic containment system was associated with reduced cat welfare. We compared 46 owned domestic cats: 23 cats that had been contained by an electronic containment system for more than 12 months (AF group); and 23 cats with no containment system that were able to roam more widely (C group). We assessed the cats’ behavioural responses and welfare via four behavioural tests (unfamiliar person test; novel object test; sudden noise test; cognitive bias test) and an owner questionnaire. In the unfamiliar person test, C group lip-licked more than the AF group, whilst the AF group looked at, explored and interacted more with the unfamiliar person than C group. In the novel object test, the AF group looked at and explored the object more than C group. No significant differences were found between AF and C groups for the sudden noise or cognitive bias tests. Regarding the questionnaire, C group owners thought their cats showed more irritable behaviour and AF owners thought that their cats toileted inappropriately more often than C owners. Overall, AF cats were less neophobic than C cats and there was no evidence of significant differences between the populations in general affective state. These findings indicate that an electronic boundary fence with clear pre-warning cues does not impair the long term quality of life of cat
A Large-Scale Rheumatoid Arthritis Genetic Study Identifies Association at Chromosome 9q33.2
Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease affecting both joints and extra-articular tissues. Although some genetic risk factors for RA are well-established, most notably HLA-DRB1 and PTPN22, these markers do not fully account for the observed heritability. To identify additional susceptibility loci, we carried out a multi-tiered, case-control association study, genotyping 25,966 putative functional SNPs in 475 white North American RA patients and 475 matched controls. Significant markers were genotyped in two additional, independent, white case-control sample sets (661 cases/1322 controls from North America and 596 cases/705 controls from The Netherlands) identifying a SNP, rs1953126, on chromosome 9q33.2 that was significantly associated with RA (ORcommon = 1.28, trend Pcomb = 1.45E-06). Through a comprehensive fine-scale-mapping SNP-selection procedure, 137 additional SNPs in a 668 kb region from MEGF9 to STOM on 9q33.2 were chosen for follow-up genotyping in a staged-approach. Significant single marker results (Pcomb<0.01) spanned a large 525 kb region from FBXW2 to GSN. However, a variety of analyses identified SNPs in a 70 kb region extending from the third intron of PHF19 across TRAF1 into the TRAF1-C5 intergenic region, but excluding the C5 coding region, as the most interesting (trend Pcomb: 1.45E-06 → 5.41E-09). The observed association patterns for these SNPs had heightened statistical significance and a higher degree of consistency across sample sets. In addition, the allele frequencies for these SNPs displayed reduced variability between control groups when compared to other SNPs. Lastly, in combination with the other two known genetic risk factors, HLA-DRB1 and PTPN22, the variants reported here generate more than a 45-fold RA-risk differential
Smaller total and subregional cerebellar volumes in posttraumatic stress disorder:a mega-analysis by the ENIGMA-PGC PTSD workgroup
Although the cerebellum contributes to higher-order cognitive and emotional functions relevant to posttraumatic stress disorder (PTSD), prior research on cerebellar volume in PTSD is scant, particularly when considering subregions that differentially map on to motor, cognitive, and affective functions. In a sample of 4215 adults (PTSD n = 1642; Control n = 2573) across 40 sites from the ENIGMA-PGC PTSD working group, we employed a new state-of-the-art deep-learning based approach for automatic cerebellar parcellation to obtain volumetric estimates for the total cerebellum and 28 subregions. Linear mixed effects models controlling for age, gender, intracranial volume, and site were used to compare cerebellum volumes in PTSD compared to healthy controls (88% trauma-exposed). PTSD was associated with significant grey and white matter reductions of the cerebellum. Compared to controls, people with PTSD demonstrated smaller total cerebellum volume, as well as reduced volume in subregions primarily within the posterior lobe (lobule VIIB, crus II), vermis (VI, VIII), flocculonodular lobe (lobule X), and corpus medullare (all p -FDR < 0.05). Effects of PTSD on volume were consistent, and generally more robust, when examining symptom severity rather than diagnostic status. These findings implicate regionally specific cerebellar volumetric differences in the pathophysiology of PTSD. The cerebellum appears to play an important role in higher-order cognitive and emotional processes, far beyond its historical association with vestibulomotor function. Further examination of the cerebellum in trauma-related psychopathology will help to clarify how cerebellar structure and function may disrupt cognitive and affective processes at the center of translational models for PTSD.</p
Smaller total and subregional cerebellar volumes in posttraumatic stress disorder:a mega-analysis by the ENIGMA-PGC PTSD workgroup
Although the cerebellum contributes to higher-order cognitive and emotional functions relevant to posttraumatic stress disorder (PTSD), prior research on cerebellar volume in PTSD is scant, particularly when considering subregions that differentially map on to motor, cognitive, and affective functions. In a sample of 4215 adults (PTSD n = 1642; Control n = 2573) across 40 sites from the ENIGMA-PGC PTSD working group, we employed a new state-of-the-art deep-learning based approach for automatic cerebellar parcellation to obtain volumetric estimates for the total cerebellum and 28 subregions. Linear mixed effects models controlling for age, gender, intracranial volume, and site were used to compare cerebellum volumes in PTSD compared to healthy controls (88% trauma-exposed). PTSD was associated with significant grey and white matter reductions of the cerebellum. Compared to controls, people with PTSD demonstrated smaller total cerebellum volume, as well as reduced volume in subregions primarily within the posterior lobe (lobule VIIB, crus II), vermis (VI, VIII), flocculonodular lobe (lobule X), and corpus medullare (all p -FDR < 0.05). Effects of PTSD on volume were consistent, and generally more robust, when examining symptom severity rather than diagnostic status. These findings implicate regionally specific cerebellar volumetric differences in the pathophysiology of PTSD. The cerebellum appears to play an important role in higher-order cognitive and emotional processes, far beyond its historical association with vestibulomotor function. Further examination of the cerebellum in trauma-related psychopathology will help to clarify how cerebellar structure and function may disrupt cognitive and affective processes at the center of translational models for PTSD.</p
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