We present a method for increasing the lateral chain density in self-assembled monolayers (SAMs) of alkanethiols on polycrystalline gold. This method relies on exposure of the alkanethiolate monolayers to mercury vapor and subsequent reimmersion into the thiol solution. Mercury adsorption on the gold surface induces a structural rearrangement in the alkanethiolate monolayers, as indicated by changes in dichroism in the Fourier transform infrared (FTIR) spectra, in line shape in the sum frequency generation (SFG) spectra, and in the macroscopic wetting behavior of the monolayers. X-ray photoelectron spectroscopy (XPS) data show that saturation of the thiolate samples with mercury occurs after 20−30 min of exposure to air saturated with mercury vapor. For 100 nm evaporated gold films a mercury bulk concentration of 14−16 atom % was determined by energy-dispersive X-ray analysis (EDX). Time-of-flight secondary ion mass spectroscopy (ToF-SIMS) data indicate that after mercury adsorption the monolayers consist of gold thiolate and mercury thiolate molecules. From the FTIR and XPS data we conclude that the mercury-exposed SAMs exhibit an inhomogeneous structure with differently tilted domains. As determined from the IR experiments, the average tilt angle of the alkyl chains in hexadecanethiolate monolayers decreases by ∼16° by mercury adsorption and by an additional ∼3° after reimmersion into the thiol solution. The corresponding changes obtained from near edge X-ray absorption fine structure (NEXAFS) spectra are ∼9° and ∼3°, respectively.
Persistent loneliness is often reported by patients with borderline personality disorder (BPD). However, empirical studies investigating this aspect of BPD psychopathology are sparse. Studies from social psychology revealed that social isolation and low social functioning contribute to loneliness, that is, the subjective feeling of being alone. The aim of the present study was to contribute to the understanding of loneliness in BPD by investigating its relation to social isolation and functioning in different domains of life. Subjective experience of loneliness was measured in 80 women (40 BPD patients, 40 healthy controls) with the UCLA Loneliness Scale. Social isolation and social functioning were assessed with the Social Network Inventory and the Social Functioning Scale. In addition, we assessed global functioning with the Global Assessment of Functioning. BPD patients reported stronger feelings of loneliness compared to healthy participants. In general, the level of loneliness was linked to network size, social engagement, and prosocial behavior. Diversity of social networks and functioning in the domain of interpersonal communication were associated with the level of loneliness only in BPD. A reduced variety of roles in social life together with impairments in interpersonal communication were particularly relevant for the experience of loneliness in BPD, suggesting an indirect path to target this psychopathological feature in therapeutic interventions. However, both social isolation and social functioning were not sufficient to explain the severely increased loneliness experienced by these patients, stressing the need for further investigation of determinants of loneliness in this clinical population. (PsycINFO Database Record
This review examines recent functional neuroimaging research of resting-state regional connectivity between brain regions in anxiety disorders. Studies compiled in the PubMedNational Center for Biotechnology Information database targeting resting-state functional connectivity in anxiety disorders were reviewed. Diagnoses included posttraumatic stress disorder (PTSD), generalized anxiety disorder (GAD), social anxiety disorder (SAD), obsessive-compulsive disorder (OCD), panic disorder (PD), and specific phobia (SP).Alterations to network connectivity were demonstrated in PTSD, GAD, SAD, OCD, and PD in several resting-state investigations. Differences from control subjects were primarily observed in the default mode network within PTSD, SAD, and OCD. Alterations within the salience network were observed primarily in PTSD, GAD, and SAD. Alterations in corticostriatal networks were uniquely observed in OCD. Finally, alterations within somatosensory networks were observed in SAD and PD investigations. Resting-state studies involving SPs as a primary diagnosis (with or without comorbidities) were not generated during the literature search. The emerging use of resting-state paradigms may be an effective method for understanding associations between anxiety disorders. Targeted studies of PD and SPs, meta-analyses of the studies conducted to date, and studies of the impact of specific comorbid presentations, are recommended future research directions. W W W Études de neuroimagerie à l'état de repos : une nouvelle façon d'identifier les différences et les similitudes des troubles anxieux?Cette revue examine la recherche récente en neuroimagerie fonctionnelle sur la connectivité régionale à l'état de repos entre les régions du cerveau dans les troubles anxieux. Des études de la base de données PubMed-National Center for Biotechnology Information portant sur la connectivité fonctionnelle à l'état de repos dans les troubles anxieux ont été examinées. Les diagnostics incluaient notamment le trouble de stress post-traumatique (TSPT), le trouble d'anxiété généralisée (TAG), le trouble d'anxiété sociale (TAS), le trouble obsessionnel-compulsif (TOC), le trouble panique (TP), et la phobie spécifique (PS). Les modifications de la connectivité du réseau ont été démontrées dans les TSPT, TAG, TAS, TOC et TP dans plusieurs investigations à l'état de repos. Les différences par rapport aux sujets témoins ont été surtout observées dans le réseau du mode par défaut dans le TSPT, le TAS, et le TOC. Les modifications du réseau de saillie ont été surtout observées dans le TSPT, le TAG, et le TAS. Les modifications des réseaux corticostriataux ont été observées seulement dans le TOC. Enfin, les modifications des réseaux somatosensoriels ont été observées dans les investigations du TAS et du TP. Les études à l'état de repos impliquant les PS comme diagnostic primaire (avec ou sans comorbidités) n'ont pas été générées durant la recherche de la littérature. L'utilisation naissante des paradigmes de l'état au repos peut se révéler une méthode ef...
Background Autobiographical memory (AM) refers to memories of events that are personally relevant and are remembered from one's own past. The AM network is a distributed brain network comprised largely by prefrontal medial and posteromedial cortical brain regions, which together facilitate AM. Autobiographical memories with high arousal and negatively valenced emotional states are thought to be retrieved more readily and re‐experienced more vividly. This is critical in the case of trauma‐related AMs, which are related to altered phenomenological experiences as well as aberrations to the underlying neural systems in posttraumatic stress disorder (PTSD). Critically, these alterations to the AM network have not been explored recently and have never been analyzed with consideration to the different processes of AM, them being retrieval and re‐experiencing. Methods We conducted a series of effect‐size signed differential mapping meta‐analyses across twenty‐eight studies investigating the neural correlates of trauma‐related AMs in participants with PTSD as compared with controls. Studies included either trauma‐related scripts or trauma‐related materials (i.e., sounds, images, pictures) implemented to evoke the recollection of a trauma‐related memory. Results The meta‐analyses revealed that control and PTSD participants displayed greater common brain activation of prefrontal medial and posteromedial cortices, respectively. Whereby the prefrontal medial cortices are suggested to facilitate retrieval monitoring, the posteromedial cortices are thought to enable the visual imagery processes of AM. Conclusions Taken together, reduced common activation of prefrontal cortices may be interpreted as a bias toward greater re‐experiencing, where the more salient elements of the traumatic memory are relived as opposed to retrieved in a controlled manner in PTSD.
A neurocircuitry model of post-traumatic stress disorder (PTSD) suggests increased amygdala responses to emotional stimuli, coupled with hypoactivation of prefrontal regions associated with cognitive control. However, results are heterogenous across different subsamples of PTSD as well as different paradigms. We investigated cognitive control in a classic and emotional Stroop task in 28 female patients with complex PTSD (cPTSD), 28 female trauma-exposed healthy controls (TCs) and 28 female non-trauma-exposed healthy controls (HCs) using functional neuroimaging. Afterwards, we assessed memory function in a spontaneous free recall and recognition task. Patients with cPTSD displayed significantly greater Stroop interference with trauma-related words (as reflected in slower reaction times and increased errors) compared to the other conditions and compared to the TC and HC groups. Moreover, patients with cPTSD showed increased activation in the context of trauma-related words in brain regions associated with cognitive control (dlPFC, vmPFC, dACC) compared to both control groups, and a trend for increased activation in the insula compared to the HC group. Increased recruitment of regions contributing to cognitive control in patients with cPTSD, together with a lack of amygdala response may point to efforts to compensate for emotional distraction caused by the trauma-related words.
This study provides the first evidence for a specific psychophysiological-neuronal profile in PTSD individuals characterized by lower resting HRV and a lack of HRV covariation with CAN-related brain connectivity. Hum Brain Mapp 38:27-40, 2017. © 2016 Wiley Periodicals, Inc.
Deleterious effects of adverse childhood experiences (ACE) on human brain volume are widely reported. First evidence points to differential effects of ACE on brain volume in terms of timing of ACE. Upcoming studies additionally point towards the impact of different types (i.e., neglect and abuse) of ACE in terms of timing. The current study aimed to investigate the correlation between retrospectively reported severity of type (i.e., the extent to which subjects were exposed to abuse and/or neglect, respectively) and timing of ACE on female brain volume in a sample of prolonged traumatized subjects. A female sample with ACE (N = 68) underwent structural magnetic resonance imaging and a structured interview exploring the severity of ACE from age 3 up to 17 using the "Maltreatment and Abuse Chronology of Exposure" (MACE). Random forest regression with conditional interference trees was applied to assess the impact of ACE severity as well as the severity of ACE type, (i.e. to what extent individuals were exposed to neglect and/or abuse) at certain ages on pre-defined regions of interest such as the amygdala, hippocampus, and anterior cingulate (ACC) volume. Analyses revealed differential type and timing-specific effects of ACE on stress sensitive brain structures: Amygdala and hippocampal volume were affected by ACE severity during a period covering preadolescence and early adolescence. Crucially, this effect was driven by the severity of neglect. Adverse childhood experiences (ACE), i.e. sexual or physical abuse or neglect during childhood, are highly prevalent worldwide 1. Particularly prolonged and repeated ACE constitutes a major risk factor for adult psychopathology 2 such as major depression 3 , substance abuse 4 , personality disorders 5 , anxiety disorders, and posttraumatic stress disorder (PTSD) 6. ACE is further linked to deleterious effects on neurocognitive functioning (i.e., working memory and inhibitory control), mirrored in significant functional and structural alterations in stress and
Individuals with post‐traumatic stress disorder (PTSD) typically experience states of reliving and hypervigilance; however, the dissociative subtype of PTSD (PTSD+DS) presents with additional symptoms of depersonalization and derealization. Although the insula is critical to emotion processing, its association with these contrasting symptom profiles is yet to be fully delineated. Accordingly, we investigated insula subregion resting‐state functional connectivity patterns among individuals with PTSD, PTSD+DS, and healthy controls. Using SPM12 and PRONTO software, we implemented a seed‐based resting‐state functional connectivity approach, along with multiclass Gaussian process classification machine learning, respectively, in order to evaluate unique patterns and the predictive validity of insula subregion connectivity among individuals with PTSD (n = 84), PTSD+DS (n = 49), and age‐matched healthy controls (n = 51). As compared to PTSD and PTSD+DS, healthy controls showed increased right anterior and posterior insula connectivity with frontal lobe structures. By contrast, PTSD showed increased bilateral posterior insula connectivity with subcortical structures, including the periaqueductal gray. Strikingly, as compared to PTSD and controls, PTSD+DS showed increased bilateral anterior and posterior insula connectivity with posterior cortices, including the left lingual gyrus and the left precuneus. Moreover, machine learning analyses were able to classify PTSD, PTSD+DS, and controls using insula subregion connectivity patterns with 80.4% balanced accuracy (p < .01). These findings suggest a neurobiological distinction between PTSD and its dissociative subtype with regard to insula subregion functional connectivity patterns. Furthermore, machine learning algorithms were able to utilize insula resting‐state connectivity patterns to discriminate between participant groups with high predictive accuracy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.