114 research outputs found
converging evidence from an intermediate phenotype approach
Representing a phylogenetically old and very basic mechanism of inhibitory
neurotransmission, glycine receptors have been implicated in the modulation of
behavioral components underlying defensive responding toward threat. As one of
the first findings being confirmed by genome-wide association studies for the
phenotype of panic disorder and agoraphobia, allelic variation in a gene
coding for the glycine receptor beta subunit (GLRB) has recently been
associated with increased neural fear network activation and enhanced acoustic
startle reflexes. On the basis of two independent healthy control samples, we
here aimed to further explore the functional significance of the GLRB genotype
(rs7688285) by employing an intermediate phenotype approach. We focused on the
phenotype of defensive system reactivity across the levels of brain function,
structure, and physiology. Converging evidence across both samples was found
for increased neurofunctional activation in the (anterior) insular cortex in
GLRB risk allele carriers and altered fear conditioning as a function of
genotype. The robustness of GLRB effects is demonstrated by consistent
findings across different experimental fear conditioning paradigms and
recording sites. Altogether, findings provide translational evidence for
glycine neurotransmission as a modulator of the brain’s evolutionary old
dynamic defensive system and provide further support for a strong,
biologically plausible candidate intermediate phenotype of defensive
reactivity. As such, glycine-dependent neurotransmission may open up new
avenues for mechanistic research on the etiopathogenesis of fear and anxiety
disorders
Altered top-down and bottom-up processing of fear conditioning in panic disorder with agoraphobia
Background: Although several neurophysiological models have been proposed for panic disorder with agoraphobia (PD/AG), there is limited evidence from functional magnetic resonance imaging (fMRI) studies on key neural networks in PD/AG. Fear conditioning has been proposed to represent a central pathway for the development and maintenance of this disorder; however, its neural substrates remain elusive. The present study aimed to investigate the neural correlates of fear conditioning in PD/AG patients.
Method: The blood oxygen level-dependent (BOLD) response was measured using fMRI during a fear conditioning task. Indicators of differential conditioning, simple conditioning and safety signal processing were investigated in 60 PD/AG patients and 60 matched healthy controls.
Results: Differential conditioning was associated with enhanced activation of the bilateral dorsal inferior frontal gyrus (IFG) whereas simple conditioning and safety signal processing were related to increased midbrain activation in PD/AG patients versus controls. Anxiety sensitivity was associated positively with the magnitude of midbrain activation.
Conclusions: The results suggest changes in top-down and bottom-up processes during fear conditioning in PD/AG that can be interpreted within a neural framework of defensive reactions mediating threat through distal (forebrain) versus proximal (midbrain) brain structures. Evidence is accumulating that this network plays a key role in the aetiopathogenesis of panic disorder
Serotonin tranporter methylation and response to cognitive behaviour therapy in children with anxiety disorders
Anxiety disorders that are the most commonly occurring psychiatric disorders in childhood, are associated with a range of social and educational impairments and often continue into adulthood. Cognitive behaviour therapy (CBT) is an effective treatment option for the majority of cases, although up to 35-45% of children do not achieve remission. Recent research suggests that some genetic variants may be associated with a more beneficial response to psychological therapy. Epigenetic mechanisms such as DNA methylation work at the interface between genetic and environmental influences. Furthermore, epigenetic alterations at the serotonin transporter (SERT) promoter region have been associated with environmental influences such as stressful life experiences. In this study, we measured DNA methylation upstream of SERT in 116 children with an anxiety disorder, before and after receiving CBT. Change during treatment in percentage DNA methylation was significantly different in treatment responders vs nonresponders. This effect was driven by one CpG site in particular, at which responders increased in methylation, whereas nonresponders showed a decrease in DNA methylation. This is the first study to demonstrate differences in SERT methylation change in association with response to a purely psychological therapy. These findings confirm that biological changes occur alongside changes in symptomatology following a psychological therapy such as CBT
Calculating the energy spectra of magnetic molecules: application of real- and spin-space symmetries
The determination of the energy spectra of small spin systems as for instance
given by magnetic molecules is a demanding numerical problem. In this work we
review numerical approaches to diagonalize the Heisenberg Hamiltonian that
employ symmetries; in particular we focus on the spin-rotational symmetry SU(2)
in combination with point-group symmetries. With these methods one is able to
block-diagonalize the Hamiltonian and thus to treat spin systems of
unprecedented size. In addition it provides a spectroscopic labeling by
irreducible representations that is helpful when interpreting transitions
induced by Electron Paramagnetic Resonance (EPR), Nuclear Magnetic Resonance
(NMR) or Inelastic Neutron Scattering (INS). It is our aim to provide the
reader with detailed knowledge on how to set up such a diagonalization scheme.Comment: 29 pages, many figure
Шляхи підвищення ефективності використання виробничих ресурсів сільськогосподарських підприємств
Single-phase polycrystalline samples and single crystals of the complex boride phases Ti8Fe3Ru18B8 and Ti7Fe4Ru18B8 have been synthesized by arc melting the elements. The phases were characterized by powder and single-crystal X-ray diffraction as well as energy-dispersive X-ray analysis. They are new substitutional variants of the Zn11Rh18B8 structure type, space group P4/mbm (no. 127). The particularity of their crystal structure lies in the simultaneous presence of dumbbells which form ladders of magnetically active iron atoms along the [001] direction and two additional mixed iron/titanium chains occupying Wyckoff sites 4h and 2b. The ladder substructure is ca. 3.0 Å from the two chains at the 4h, which creates the sequence chain–ladder–chain, establishing a new structural and magnetic motif, the scaffold. The other chain (at 2b) is separated by at least 6.5 Å from this scaffold. According to magnetization measurements, Ti8Fe3Ru18B8 and Ti7Fe4Ru18B8 order ferrimagnetically below 210 and 220 K, respectively, with the latter having much higher magnetic moments than the former. However, the magnetic moment observed for Ti8Fe3Ru18B8 is unexpectedly smaller than the recently reported Ti9Fe2Ru18B8 ferromagnet. The variation of the magnetic moments observed in these new phases can be adequately understood by assuming a ferrimagnetic ordering involving the three different iron sites. Furthermore, the recorded hysteresis loops indicate a semihard magnetic behavior for the two phases. The highest Hc value (28.6 kA/m), measured for Ti7Fe4Ru18B8, lies just at the border of those of hard magnetic materials
ENIGMA and global neuroscience: A decade of large-scale studies of the brain in health and disease across more than 40 countries
This review summarizes the last decade of work by the ENIGMA (Enhancing NeuroImaging Genetics through Meta Analysis) Consortium, a global alliance of over 1400 scientists across 43 countries, studying the human brain in health and disease. Building on large-scale genetic studies that discovered the first robustly replicated genetic loci associated with brain metrics, ENIGMA has diversified into over 50 working groups (WGs), pooling worldwide data and expertise to answer fundamental questions in neuroscience, psychiatry, neurology, and genetics. Most ENIGMA WGs focus on specific psychiatric and neurological conditions, other WGs study normal variation due to sex and gender differences, or development and aging; still other WGs develop methodological pipelines and tools to facilitate harmonized analyses of "big data" (i.e., genetic and epigenetic data, multimodal MRI, and electroencephalography data). These international efforts have yielded the largest neuroimaging studies to date in schizophrenia, bipolar disorder, major depressive disorder, post-traumatic stress disorder, substance use disorders, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorders, epilepsy, and 22q11.2 deletion syndrome. More recent ENIGMA WGs have formed to study anxiety disorders, suicidal thoughts and behavior, sleep and insomnia, eating disorders, irritability, brain injury, antisocial personality and conduct disorder, and dissociative identity disorder. Here, we summarize the first decade of ENIGMA's activities and ongoing projects, and describe the successes and challenges encountered along the way. We highlight the advantages of collaborative large-scale coordinated data analyses for testing reproducibility and robustness of findings, offering the opportunity to identify brain systems involved in clinical syndromes across diverse samples and associated genetic, environmental, demographic, cognitive, and psychosocial factors
Mega‐analysis methods in ENIGMA: the experience of the generalized anxiety disorder working group
Pathways through Adolescenc
Retinal Vascular Occlusion after COVID-19 Vaccination : More Coincidence than Causal Relationship? Data from a Retrospective Multicentre Study
Background: To investigate whether vaccination against SARS-CoV-2 is associated with
the onset of retinal vascular occlusive disease (RVOD). Methods: In this multicentre study, data
from patients with central and branch retinal vein occlusion (CRVO and BRVO), central and branch
retinal artery occlusion (CRAO and BRAO), and anterior ischaemic optic neuropathy (AION) were
retrospectively collected during a 2-month index period (1 June–31 July 2021) according to a defined
protocol. The relation to any previous vaccination was documented for the consecutive case series.
Numbers of RVOD and COVID-19 vaccination were investigated in a case-by-case analysis. A case–
control study using age- and sex-matched controls from the general population (study participants
from the Gutenberg Health Study) and an adjusted conditional logistic regression analysis was
conducted. Results: Four hundred and twenty-one subjects presenting during the index period
(61 days) were enrolled: one hundred and twenty-one patients with CRVO, seventy-five with BRVO,
fifty-six with CRAO, sixty-five with BRAO, and one hundred and four with AION. Three hundred
and thirty-two (78.9%) patients had been vaccinated before the onset of RVOD. The vaccines given
were BNT162b2/BioNTech/Pfizer (n = 221), followed by ChadOx1/AstraZeneca (n = 57), mRNA1273/Moderna (n = 21), and Ad26.COV2.S/Johnson & Johnson (n = 11; unknown n = 22). Our
case–control analysis integrating population-based data from the GHS yielded no evidence of an
increased risk after COVID-19 vaccination (OR = 0.93; 95% CI: 0.60–1.45, p = 0.75) in connection with
a vaccination within a 4-week window. Conclusions: To date, there has been no evidence of any
association between SARS-CoV-2 vaccination and a higher RVOD risk
Bupropion for the treatment of apathy in Huntington's disease:A multicenter, randomised, double-blind, placebo-controlled, prospective crossover trial
OBJECTIVE:To evaluate the efficacy and safety of bupropion in the treatment of apathy in Huntington's disease (HD). METHODS:In this phase 2b multicentre, double-blind, placebo-controlled crossover trial, individuals with HD and clinical signs of apathy according to the Structured Clinical Interview for Apathy-Dementia (SCIA-D), but not depression (n = 40) were randomized to receive either bupropion 150/300mg or placebo daily for 10 weeks. The primary outcome parameter was a significant change of the Apathy Evaluation Scale (AES) score after ten weeks of treatment as judged by an informant (AES-I) living in close proximity with the study participant. The secondary outcome parameters included changes of 1. AES scores determined by the patient (AES-S) or the clinical investigator (AES-C), 2. psychiatric symptoms (NPI, HADS-SIS, UHDRS-Behavior), 3. cognitive performance (SDMT, Stroop, VFT, MMSE), 4. motor symptoms (UHDRS-Motor), 5. activities of daily function (TFC, UHDRS-Function), and 6. caregiver distress (NPI-D). In addition, we investigated the effect of bupropion on brain structure as well as brain responses and functional connectivity during reward processing in a gambling task using magnetic resonance imaging (MRI). RESULTS:At baseline, there were no significant treatment group differences in the clinical primary and secondary outcome parameters. At endpoint, there was no statistically significant difference between treatment groups for all clinical primary and secondary outcome variables. Study participation, irrespective of the intervention, lessened symptoms of apathy according to the informant and the clinical investigator. CONCLUSION:Bupropion does not alleviate apathy in HD. However, study participation/placebo effects were observed, which document the need for carefully controlled trials when investigating therapeutic interventions for the neuropsychiatric symptoms of HD. TRIAL REGISTRATION:ClinicalTrials.gov 01914965
- …