472 research outputs found
Callous-unemotional traits, low cortisol reactivity and physical aggression in children: findings from the Wirral Child Health and Development Study
Callous-unemotional (CU) traits are thought to confer risk for aggression via reduced amygdala responsivity to distress cues in others. Low cortisol reactivity is thought to confer risk for aggression via reduced arousal and this effect may be confined to boys. We tested the hypothesis that the association between childhood CU traits and aggression would be greatest in the absence of the inhibitory effects of cortisol reactivity, and that this effect would be sex dependent. Participants were 283 members of a stratified subsample within an epidemiological longitudinal cohort (WCHADS). Cortisol reactivity to a social stressor was assessed at 5 years. CU traits were reported by mothers at 5 years, and physical aggression by mothers and teachers at age 7. Results showed that CU traits were associated with elevated aggression at 7 years controlling for earlier aggression. There was no main effect of cortisol reactivity on regression. The association between CU traits and aggression was moderated by cortisol reactivity (p = .011) with a strong association between CU traits and aggression in the presence of low reactivity, and a small and non-significant association in the presence of high reactivity. This association was further moderated by child sex (p = .041) with the joint effect of high CU traits and low cortisol reactivity seen only in boys (p = .016). We report first evidence that a combined deficit in inhibitory processes associated with CU traits and low cortisol reactivity increases risk for childhood aggression, in a sex-dependent manner
The gray matter volume of the amygdala is correlated with the perception of melodic intervals: a voxel-based morphometry study
Music is not simply a series of organized pitches, rhythms, and timbres, it is capable of evoking emotions. In the present study, voxel-based morphometry (VBM) was employed to explore the neural basis that may link music to emotion. To do this, we identified the neuroanatomical correlates of the ability to extract pitch interval size in a music segment (i.e., interval perception) in a large population of healthy young adults (N = 264). Behaviorally, we found that interval perception was correlated with daily emotional experiences, indicating the intrinsic link between music and emotion. Neurally, and as expected, we found that interval perception was positively correlated with the gray matter volume (GMV) of the bilateral temporal cortex. More important, a larger GMV of the bilateral amygdala was associated with better interval perception, suggesting that the amygdala, which is the neural substrate of emotional processing, is also involved in music processing. In sum, our study provides one of first neuroanatomical evidence on the association between the amygdala and music, which contributes to our understanding of exactly how music evokes emotional responses
Neuroimaging Evidence of Major Morpho-Anatomical and Functional Abnormalities in the BTBR T+TF/J Mouse Model of Autism
BTBR T+tf/J (BTBR) mice display prominent behavioural deficits analogous to the defining symptoms of autism, a feature that has prompted a widespread use of the model in preclinical autism research. Because neuro-behavioural traits are described with respect to reference populations, multiple investigators have examined and described the behaviour of BTBR mice against that exhibited by C57BL/6J (B6), a mouse line characterised by high sociability and low self-grooming. In an attempt to probe the translational relevance of this comparison for autism research, we used Magnetic Resonance Imaging (MRI) to map in both strain multiple morpho-anatomical and functional neuroimaging readouts that have been extensively used in patient populations. Diffusion tensor tractography confirmed previous reports of callosal agenesis and lack of hippocampal commissure in BTBR mice, and revealed a concomitant rostro-caudal reorganisation of major cortical white matter bundles. Intact inter-hemispheric tracts were found in the anterior commissure, ventro-medial thalamus, and in a strain-specific white matter formation located above the third ventricle. BTBR also exhibited decreased fronto-cortical, occipital and thalamic gray matter volume and widespread reductions in cortical thickness with respect to control B6 mice. Foci of increased gray matter volume and thickness were observed in the medial prefrontal and insular cortex. Mapping of resting-state brain activity using cerebral blood volume weighted fMRI revealed reduced cortico-thalamic function together with foci of increased activity in the hypothalamus and dorsal hippocampus of BTBR mice. Collectively, our results show pronounced functional and structural abnormalities in the brain of BTBR mice with respect to control B6 mice. The large and widespread white and gray matter abnormalities observed do not appear to be representative of the neuroanatomical alterations typically observed in autistic patients. The presence of reduced fronto-cortical metabolism is of potential translational relevance, as this feature recapitulates previously-reported clinical observations
Monitoring HSVtk suicide gene therapy: the role of [18F]FHPG membrane transport
Favourable pharmacokinetics of the prodrug are essential for successful HSVtk/ganciclovir (GCV) suicide gene therapy. [F-18] FHPG PET might be a suitable technique to assess the pharmacokinetics of the prodrug GCV noninvasively, provided that [F-18] FHPG mimics the behaviour of GCV. Since membrane transport is an important aspect of the pharmacokinetics of the prodrug, we investigated the cellular uptake mechanism of [F-18] FHPG in an HSVtk expressing C6 rat glioma cell line and in tumour- bearing rats. The nucleoside transport inhibitors dipyridamol, NBMPR and 2- chloroadenosine did not significantly affect the [F-18] FHPG uptake in vitro. Thymidine and uridine significantly decreased [F-18] FHPG uptake by 84 and 58%, respectively, but an enzyme assay revealed that this decline was due to inhibition of the HSVtk enzyme rather than membrane transport. Nucleobase transport inhibitors, thymine and adenine, caused a 58 and 55% decline in tracer uptake, respectively. In vivo, the ratio of [F-18] FHPG uptake in C6tk and C6 tumours decreased from 3.070.5 to 1.070.2 after infusion of adenine. Thus, in our tumour model, [F-18] FHPG transport exclusively occurred via purine nucleobase transport. In this respect, FHPG does not resemble GCV, which is predominantly taken up via the nucleoside transporter, but rather acyclovir, which is also taken up via the purine nucleobase carrier
photoproduction on the proton for photon energies from 0.725 to 2.875 GeV
Differential cross sections for the reaction have been
measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged
photon beam with energies from 0.725 to 2.875 GeV. Where available, the results
obtained here compare well with previously published results for the reaction.
Agreement with the SAID and MAID analyses is found below 1 GeV. The present set
of cross sections has been incorporated into the SAID database, and exploratory
fits have been made up to 2.7 GeV. Resonance couplings have been extracted and
compared to previous determinations. With the addition of these cross sections
to the world data set, significant changes have occurred in the high-energy
behavior of the SAID cross-section predictions and amplitudes.Comment: 18 pages, 10 figure
Observation of an Exotic Baryon in Exclusive Photoproduction from the Deuteron
In an exclusive measurement of the reaction , a
narrow peak that can be attributed to an exotic baryon with strangeness
is seen in the invariant mass spectrum. The peak is at
GeV/c with a measured width of 0.021 GeV/c FWHM, which is largely
determined by experimental mass resolution. The statistical significance of the
peak is . The mass and width of the observed peak are
consistent with recent reports of a narrow baryon by other experimental
groups.Comment: 5 pages, 5 figure
Measurement of Beam-Spin Asymmetries for Deep Inelastic Electroproduction
We report the first evidence for a non-zero beam-spin azimuthal asymmetry in
the electroproduction of positive pions in the deep-inelastic region. Data have
been obtained using a polarized electron beam of 4.3 GeV with the CLAS detector
at the Thomas Jefferson National Accelerator Facility (JLab). The amplitude of
the modulation increases with the momentum of the pion relative to
the virtual photon, , with an average amplitude of for range.Comment: 5 pages, RevTEX4, 3 figures, 2 table
Measurement of the Polarized Structure Function for in the Resonance Region
The polarized longitudinal-transverse structure function
has been measured in the resonance region at and 0.65
GeV. Data for the reaction were taken at Jefferson Lab
with the CEBAF Large Acceptance Spectrometer (CLAS) using longitudinally
polarized electrons at an energy of 1.515 GeV. For the first time a complete
angular distribution was measured, permitting the separation of different
non-resonant amplitudes using a partial wave analysis. Comparison with previous
beam asymmetry measurements at MAMI indicate a deviation from the predicted
dependence of using recent phenomenological
models.Comment: 5 pages, LaTex, 4 eps figures: to be published in PRC/Rapid
Communications. Version 2 has revised Q^2 analysi
Two-Nucleon Momentum Distributions Measured in 3He(e,e'pp)n
We have measured the 3He(e,e'pp)n reaction at 2.2 GeV over a wide kinematic
range. The kinetic energy distribution for `fast' nucleons (p > 250 MeV/c)
peaks where two nucleons each have 20% or less, and the third nucleon has most
of the transferred energy. These fast pp and pn pairs are back-to-back with
little momentum along the three-momentum transfer, indicating that they are
spectators. Experimental and theoretical evidence indicates that we have
measured distorted two-nucleon momentum distributions by striking the third
nucleon and detecting the spectator correlated pair.Comment: 6 pages, 5 figures, submitted to PR
Survey of A_LT' asymmetries in semi-exclusive electron scattering on He4 and C12
Single spin azimuthal asymmetries A_LT' were measured at Jefferson Lab using
2.2 and 4.4 GeV longitudinally polarized electrons incident on He4 and C12
targets in the CLAS detector. A_LT' is related to the imaginary part of the
longitudinal-transverse interference and in quasifree nucleon knockout it
provides an unambiguous signature for final state interactions (FSI).
Experimental values of A_LT' were found to be below 5%, typically |A_LT'| < 3%
for data with good statistical precision. Optical Model in Eikonal
Approximation (OMEA) and Relativistic Multiple-Scattering Glauber Approximation
(RMSGA) calculations are shown to be consistent with the measured asymmetries.Comment: 9 pages, 5 figure
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