Este artículo examina Los diarios de Emilio Renzi a fin de informar sobre la investigación que realizó Ricardo Piglia a finales de los años sesenta para una novela, Plata quemada, que no se ...publicaría hasta 1997.
Anxiety disorders are the most common mental health disorder. Therefore, elucidating brain mechanisms implicated in anxiety disorders is important avenue for developing novel treatments and improving ...care. The dorsolateral prefrontal cortex (dlPFC) is thought to be critically involved in working memory processes (i.e. maintenance, manipulation, suppression, etc.). In addition, there is evidence that this region is involved in anxiety regulation. However, it is unclear how working memory related dlPFC processes contribute to anxiety regulation. Furthermore, we know that laterality plays an important role in working memory related dlPFC processing, however there is no current model of dlPFC mediated anxiety regulation that accounts for potential laterality effects. To address this gap, we propose a potential framework where the dlPFC contributes to emotion regulation via working memory processing. According to this framework, working memory is a fundamental process executed by the dlPFC. However, the domain of content differs across the left and right dlPFC, with the left dlPFC sensitive to primarily verbal content, and the right dlPFC sensitive to primarily non-verbal (affective content). Critically, working memory processes allow for both the retention and suppression of affective information in working memory and the overall net effect of processing on mood will depend on the balance of retention and suppression, the valence of the information being processed (positive vs. negative), and the domain of the information (verbal vs. non-verbal). If accurate, the proposed framework predicts that effects of neuromodulation targeting the dlPFC may be dependent upon the context during which the stimulation is presented.
This article is part of the Special Issue on 'Fear, Anxiety and PTSD'.
•We propose a model relating dlPFC-mediated emotion regulation to working memory.•We argue that working memory is the fundamental process executed by the dlPFC.•We argue that only the content domain differs across the left and right dlPFC.•Left dlPFC can maintain or suppress verbal content in working memory.•Right dlPFC can maintain or suppress non-verbal content in working memory.
It has long been established that individuals with anxiety disorders tend to overgeneralize attributes of fearful stimuli to nonfearful stimuli, but there is little mechanistic understanding of the ...neural system that supports overgeneralization. To address this gap in our knowledge, this study examined effect of experimentally induced anxiety in humans on generalization using the behavioral pattern separation (BPS) paradigm. Healthy subjects of both sexes encoded and retrieved novel objects during periods of safety and threat of unpredictable shocks while we recorded brain activity with fMRI. During retrieval, subjects were instructed to differentiate among new, old, and altered images. We hypothesized that the hippocampus and dorsolateral prefrontal cortex (dlPFC) would play a key role in the effect of anxiety on BPS. The dlPFC, but not the hippocampus, showed increased activity for altered images compared with old images when retrieval occurred during periods of threat compared with safety. In addition, accuracy for altered items retrieved during threat was correlated with dlPFC activity. Together, these results suggest that overgeneralization in anxiety patients may be mediated by an inability to recruit the dlPFC, which mediates the cognitive control needed to overcome anxiety and differentiate between old and altered items during periods of threat.
Anxiety and posttraumatic stress disorder patients generalize fear to nonfearful fear stimuli, making it difficult to regulate anxiety. Understanding how anxiety affects generalization is key to understanding the overgeneralization experienced by these patients. We examined this relationship in healthy subjects by studying how threat of shock affects neural responses to previously encountered stimuli. Although previous studies point to hippocampal involvement, we found that threat affected activity in the dorsolateral prefrontal cortex (dlPFC), rather than the hippocampus, when subjects encountered slightly altered versions of the previously encountered items. Importantly, this dlPFC activity predicted performance for these items. Together, these results suggest that the dlPFC is important for discrimination during elevated anxiety and that overgeneralization may reflect a deficit in dlPFC-mediated cognitive control.
The role of consciousness in learning has been debated for nearly 50 years. Recent studies suggest that conscious awareness is needed to bridge the gap when learning about two events that are ...separated in time, as is true for trace fear conditioning. This has been repeatedly shown and seems to apply to other forms of classical conditioning as well. In contrast to these findings, we show that individuals can learn to associate a face with the later occurrence of a shock, even if they are unable to perceive the face. We used a novel application of magnetoencephalography (MEG) to non-invasively record neural activity from the amygdala, which is known to be important for fear learning. We demonstrate rapid (∼ 170-200 ms) amygdala responses during the stimulus free period between the face and the shock. These results suggest that unperceived faces can serve as signals for impending threat, and that rapid, automatic activation of the amygdala contributes to this process. In addition, we describe a methodology that can be applied in the future to study neural activity with MEG in other subcortical structures.
Objective
There are conflicting data regarding the accuracy of thoracic point‐of‐care ultrasound (POCUS) in detecting traumatic pneumothorax (PTX). The purpose of our study was to determine the ...accuracy of thoracic POCUS performed by emergency physicians for the detection of clinically significant PTX in blunt and penetrating trauma patients.
Methods
We conducted a retrospective institutional review board–approved study of trauma patients 15 years or older presenting to our urban Level I academic trauma center from December 2021 to June 2022. All study patients were imaged with single‐view chest radiography (CXR) and thoracic POCUS. The presence or absence of PTX was determined by multidetector computed tomography (CT) or CXR and ultrasound (US) with tube thoracostomy placement.
Results
A total of 846 patients were included, with 803 (95%) sustaining blunt trauma. POCUS identified 13/15 clinically significant PTXs (defined as ≥35 mm of pleural separation on a blinded overread or placement of a tube thoracostomy prior to CT) with a sensitivity of 87% (95% confidence interval CI 58–97), specificity of 100% (95% CI 99–100), positive predictive value of 81% (95% CI 54%–95%), and negative predictive value of 100% (95% CI 99%–100%). The positive likelihood ratio was 484 and the negative likelihood ratio was 0.1. CXR identified eight (53%) clinically significant PTXs, with a sensitivity of 53% (95% CI 27%–78%) and a specificity of 100%, when correlated with the CT. The most common reason for a missed PTX identified on expert‐blinded overread was failure to recognize a lung point sign that was present on US.
Conclusions
Thoracic POCUS accurately identifies the majority of clinically significant PTXs in both blunt and penetrating trauma patients. Common themes for false‐negative thoracic US in the expert‐blinded overread process identified key gaps in training to inspire US education and medical education research.
Depression is a common mental disorder characterized by heterogeneous cognitive and behavioral symptoms. The emerging research paradigm of functional connectomics has provided a quantitative ...theoretical framework and analytic tools for parsing variations in the organization and function of brain networks in depression. In this review, we first discuss recent progress in depression-associated functional connectome variations. We then discuss treatment-specific brain network outcomes in depression and propose a hypothetical model highlighting the advantages and uniqueness of each treatment in relation to the modulation of specific brain network connectivity and symptoms of depression. Finally, we look to the future promise of combining multiple treatment types in clinical practice, using multisite datasets and multimodal neuroimaging approaches, and identifying biological depression subtypes.
Psychopathic behavior has long been attributed to a fundamental deficit in fear that arises from impaired amygdala function. Growing evidence has demonstrated that fear-potentiated startle (FPS) and ...other psychopathy-related deficits are moderated by focus of attention, but to date, no work on adult psychopathy has examined attentional modulation of the amygdala or concomitant recruitment of relevant attention-related circuitry. Consistent with previous FPS findings, here we report that psychopathy-related differences in amygdala activation appear and disappear as a function of goal-directed attention. Specifically, decreased amygdala activity was observed in psychopathic offenders only when attention was engaged in an alternative goal-relevant task prior to presenting threat-relevant information. Under this condition, psychopaths also exhibited greater activation in selective-attention regions of the lateral prefrontal cortex (LPFC) than did nonpsychopaths, and this increased LPFC activation mediated psychopathy’s association with decreased amygdala activation. In contrast, when explicitly attending to threat, amygdala activation did not differ in psychopaths and nonpsychopaths. This pattern of amygdala activation highlights the potential role of LPFC in mediating the failure of psychopathic individuals to process fear and other important information when it is peripheral to the primary focus of goal-directed attention.
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