Publications by authors named "Ryan Webler"

Theoretical and methodological research on threat conditioning provides important neuroscience-informed approaches to studying fear and anxiety. The threat conditioning framework is at the vanguard of physiological and neurobiological research into core mechanistic symptoms of anxiety-related psychopathology, providing detailed models of neural circuitry underlying variability in clinically relevant behaviors (e.g.

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Background: Structural and functional neurobiological abnormalities have been observed in schizophrenia. Previous studies have concentrated on specific illness stages, obscuring relationships between functional/structural changes and disorder progression. The present study aimed to quantify structural and functional abnormalities across different clinical stages using functional near-infrared spectroscopy (fNIRS) and structural magnetic resonance imaging (sMRI).

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Exposure therapy is a first-line, empirically validated treatment for anxiety, obsessive-compulsive, and trauma-related disorders. Extinction learning is the predominant theoretical framework for exposure therapy, whereby repeated disconfirmation of a feared outcome yields fear reduction over time. Although this framework has strong empirical support and substantial translational utility, extinction learning is unlikely to be the sole process underlying the therapeutic effects of exposure therapy.

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Background: Fear overgeneralization is a promising pathogenic mechanism of clinical anxiety. A dominant model posits that hippocampal pattern separation failures drive overgeneralization. Hippocampal network-targeted transcranial magnetic stimulation (HNT-TMS) has been shown to strengthen hippocampal-dependent learning/memory processes.

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Article Synopsis
  • Transcranial magnetic stimulation (TMS) and deep brain stimulation (DBS) show potential in treating anxiety but lack a standardized method for identifying new targets.
  • Researchers found a common brain circuit linked to anxiety through various experiments, revealing that specific TMS and lesion sites influenced anxiety levels.
  • The study indicates that different brain circuit connections can predict changes in anxiety and highlights a new method for finding targeted treatments across various neuropsychiatric disorders.
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Laboratory threat extinction paradigms and exposure-based therapy both involve repeated, safe confrontation with stimuli previously experienced as threatening. This fundamental procedural overlap supports laboratory threat extinction as a compelling analogue of exposure-based therapy. Threat extinction impairments have been detected in clinical anxiety and may contribute to exposure-based therapy non-response and relapse.

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Background: Findings from correlative neuroimaging studies link increased frontoparietal network (FPN) activation and default mode network (DMN) deactivation to enhanced high cognitive demand processing. To causally investigate FPN-DMN contributions to high cognitive demand processing, the current interleaved TMS-fMRI study simultaneously manipulated and indexed neural activity while tracking cognitive performance during high and low cognitive load conditions.

Methods: Twenty participants completed an n-back task consisting of four conditions (0-back, 0-backTMS, 2-back, 2-backTMS) while undergoing interleaved TMS-fMRI.

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Background And Objectives: Fear conditioning represents the prevailing model by which organisms acquire novel threat contingencies. However, little work has been devoted to linking laboratory measures of fear conditioning to the development of real-world threat responses. To fill this gap, the present study explored whether individual differences in a laboratory-based fear conditioning measure could predict levels of COVID-19-related anxiety and avoidance assessed during the first month of the pandemic.

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Fear generalization to stimuli resembling a conditioned danger-cue (CS+) is a fundamental dynamic of classical fear-conditioning. Despite the ubiquity of fear generalization in human experience and its known pathogenic contribution to clinical anxiety, neural investigations of human generalization have only recently begun. The present work provides the first meta-analysis of this growing literature to delineate brain substrates of conditioned fear-generalization and formulate a working neural model.

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Introduction: Ketamine has emerged as a rapid-acting antidepressant. While ongoing treatment can prevent relapse, concerns exist regarding long-term exposure.

Objective: We conducted a randomized trial to examine the feasibility and efficacy of cognitive behavioral therapy (CBT) following intravenous ketamine in treatment-resistant depression (TRD).

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Background: Prefrontal abnormalities in schizophrenia have consistently emerged from resting state and cognitive neuroimaging studies. However, these correlative findings require causal verification via combined imaging/stimulation approaches. To date, no interleaved transcranial magnetic stimulation and functional magnetic resonance imaging study (TMS fMRI) has probed putative prefrontal cortex abnormalities in schizophrenia.

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Introduction: Pattern separation aids cognitive flexibility by reducing interference between closely related memories. Dentate gyrus (DG) neurogenesis may facilitate pattern separation by blocking memory retrieval via inhibition of non-neurogenic downstream CA3 neurons. We hypothesized that immature adult-born DG neurons would be associated with decreased CA3 activation and increased cognitive flexibility.

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Background: Serum brain-derived neurotrophic factor (BDNF) is decreased in individuals with major depressive disorder (MDD). Pre-clinical and clinical reports suggest that the glutamate release inhibitor riluzole increases BDNF and may have antidepressant properties. Here we report serum (sBDNF) and plasma (pBDNF) levels from a randomized controlled, adjunctive, sequential parallel comparison design trial of riluzole in MDD.

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Objective: Ketamine has emerged as a rapid-acting antidepressant, though controversy remains whether sufficient data exist to justify its use outside of research protocols. In October 2014, the authors' institution began providing ketamine as an off-label therapy on a case-by-case basis for patients unable to participate in research protocols. Here, the participant experience during 29 months of providing ketamine as a clinical treatment for severe and treatment-resistant mood disorders through February 2017 is described.

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Introduction: The neurometabolism underlying the cognitive and affective symptoms associated with generalized anxiety disorder (GAD) remain poorly understood. After we have linked worry to intelligence in patients with GAD, we hypothesized that aberrant neurometabolic correlations between hippocampus and neocortical regions may underlie a shared substrate in GAD patients for both anxiety sensitivity and intelligence.

Methods: GAD patients (n = 16; F = 11) and healthy volunteers (n = 16; F = 10) were assessed using H-MRSI.

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