Existence of Chandrasekhar's limit in generalized uncertainty white dwarfs.
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ABSTRACT:
SUBMITTER: Mathew A
PROVIDER: S-EPMC8187993 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundIntolerance of uncertainty (IU), perceived attentional control (AC), and poor cognitive control abilities are risk factors for anxiety; however, few studies have examined their interactive effects in relation to anxiety. A more complete understanding of interplay between IU, perceived AC, and cognitive control could inform intervention efforts.MethodsThe current study examined the direct and interactive effects of IU and AC on anxiety in a sample of 280 community outpatients (M age = 36.01 years, SD = 16.17). Perceived AC was measured using self-report and cognitive control abilities were measured using a Go/No-Go task.ResultsFindings indicated a significant IU by perceived AC interaction predicting worry and GAD diagnoses. There was a positive relation between IU and worry/GAD diagnoses that was strongest among those with high perceived AC. Perceived AC was unrelated to cognitive control abilities, and cognitive control abilities did not interact significantly with IU. Cognitive control abilities were related to worry symptoms but not to GAD diagnoses.ConclusionsThese results indicate that at high levels of perceived AC, individuals with elevated IU report higher levels of worry, potentially due to the conscious use of worry as an emotion regulation strategy. Clinical implications and future directions are discussed.
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Project description:OBJECTIVES:Idiopathic-generalized epilepsy (IGE) is currently considered to be a genetic disease without structural alterations on conventional MRI. However, voxel-based morphometry has shown abnormalities in IGE. Another method to analyze the microstructure of the brain is diffusion-tensor imaging (DTI). We sought to clarify which structural alterations are present in IGE and the most frequent subsyndrome juvenile myoclonic epilepsy (JME). EXPERIMENTAL DESIGN:We studied 25 patients (13 IGE and 12 JME) and 44 healthy controls with DTI. Fractional anisotropy (FA), mean diffusivity (MD), axial and radial diffusivity (AD/RD) were calculated and group differences were analyzed using tract-based spatial statistics (TBSS). Additionally we performed a target-based classification of TBSS results based on the Freesurfer cortical regions. PRINCIPLE OBSERVATIONS: TBSS showed widespread FA reductions as well as MD and RD increases in patients compared to controls. Affected areas were corpus callosum, corticospinal tract, superior and inferior longitudinal fasciculus and supplementary motor regions. No significant differences were found between JME and IGE subgroups. The target-based classification confirmed a particular involvement of the superior frontal gyrus (mesiofrontal area) in IGE/ME. CONCLUSIONS:IGE and JME patients showed clear microstructural alterations in several large white matter tracts. Similar findings have been reported in rodent models of IGE. Previous, region-of-interest-based DTI studies may have under-estimated the spatial extent of structural loss associated with generalized epilepsy. The comparison of clinically defined JME and IGE groups revealed no significant DTI differences in our cohort.
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Project description:BackgroundRecent evidence suggests that repetitive transcranial magnetic stimulation (rTMS) might be effective in treating generalized anxiety disorder (GAD). Cognitive models of GAD highlight the role of intolerance of uncertainty (IU) in precipitating and maintaining worry, and it has been hypothesized that patients with GAD exhibit decision-making deficits under uncertain conditions. Improving understanding of the neural mechanisms underlying cognitive deficits associated with IU may lead to the identification of novel rTMS treatment targets and optimization of treatment parameters. The current report describes two interrelated studies designed to identify and verify a potential neural target for rTMS treatment of GAD.MethodsStudy I explored the integrity of prefrontal cortex (PFC) and amygdala neural networks, which underlie decision making under conditions of uncertainty, in GAD. Individuals diagnosed with GAD (n = 31) and healthy controls (n = 20) completed a functional magnetic resonance imaging (fMRI) gambling task that manipulated uncertainty using high versus low error rates. In a subsequent randomized-controlled trial (Study II), a subset of the GAD sample (n = 16) completed the fMRI gambling task again after 30 sessions of active versus sham rTMS (1 Hz, right dorsolateral prefrontal cortex) to investigate the modulation of functional networks and symptoms.ResultsIn Study I, participants with GAD demonstrated impairments in PFC-PFC and PFC-amygdala functional connectivity (FC) mostly during the high uncertainty condition. In Study II, one region of interest pair, dorsal anterior cingulate (ACC) - subgenual ACC, showed "normalization" of FC following active, but not sham, rTMS, and neural changes were associated with improvement in worry symptoms.ConclusionsThese results outline a possible treatment mechanism of rTMS in GAD, and pave the way for future studies of treatment optimization.
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