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Open Access Publications from the University of California

Scholarly Works (54 results)

  • Article
  • Peer Reviewed
UCLA Previously Published Works (2013)
BACKGROUND: Although interpretation biases are well documented among youth with anxiety disorders, understanding of their neural correlates is limited. In particular, there has been little study of how anxious youth neurobiologically represent changing contextual cues that may trigger anxiety. This study examined neural responses during a task in which participants viewed neutral faces paired with experimentally manipulated contextual stimuli. METHODS: Participants (16 youth with a primary anxiety disorder diagnosis and 15 age- and gender-matched controls) passively viewed neutral faces that were paired with either neutral descriptive vignettes or with vignettes that were potentially anxiety provoking (for example, those that involved performance/social evaluation). RESULTS: The two groups were differentiated by their medial prefrontal cortex (mPFC) responses, such that context modulated mPFC activation in anxious youth while non-anxious youth demonstrated no such differentiation. Counter to expectations, the performance/evaluation frames were not associated with amygdala reactivity for either group. CONCLUSIONS: The present investigation is among the first to identify how context modulates mPFC responding to neutral stimuli among anxious youth. It takes an important step toward understanding the neurobiological correlates underlying interpretation biases of neutral stimuli in this population.
    Cover page: Contextual modulation of medial prefrontal cortex to neutral faces in anxious adolescents.
    • Article
    • Peer Reviewed
    UCLA Previously Published Works (2013)
    Abstract Background Although interpretation biases are well documented among youth with anxiety disorders, understanding of their neural correlates is limited. In particular, there has been little study of how anxious youth neurobiologically represent changing contextual cues that may trigger anxiety. This study examined neural responses during a task in which participants viewed neutral faces paired with experimentally manipulated contextual stimuli. Methods Participants (16 youth with a primary anxiety disorder diagnosis and 15 age- and gender-matched controls) passively viewed neutral faces that were paired with either neutral descriptive vignettes or with vignettes that were potentially anxiety provoking (for example, those that involved performance/social evaluation). Results The two groups were differentiated by their medial prefrontal cortex (mPFC) responses, such that context modulated mPFC activation in anxious youth while non-anxious youth demonstrated no such differentiation. Counter to expectations, the performance/evaluation frames were not associated with amygdala reactivity for either group. Conclusions The present investigation is among the first to identify how context modulates mPFC responding to neutral stimuli among anxious youth. It takes an important step toward understanding the neurobiological correlates underlying interpretation biases of neutral stimuli in this population.
      Cover page: Contextual modulation of medial prefrontal cortex to neutral faces in anxious adolescents
      • Thesis
      • Peer Reviewed
      UCLA Electronic Theses and Dissertations (2018)

      In a political environment where information competes with “fake news” and partisanship dictates what is believed, voters must separate the two or be deceived. Though accurate information about politicians and policies is available, misperceptions persist, and increasing polarization in the government and the electorate exacerbate the reluctance to consume information that conflicts with existing attitudes. In this paper I identify the sources of information that affect people’s ability to correctly place Congressional candidates on the ideological spectrum and the factors that are associated with misperceptions of ideology. I draw on Bawn and Zaller’s notion of the electoral blind spot to illustrate the degree and skew of misperception in the electorate. I do this for major candidates, both incumbents and challengers, for the US House of Representatives and US Senate between 2006 and 2014. Results suggest that voters are generally unable to discern degrees of partisanship in their candidates. Voters tend to believe candidates are more moderate than they are in reality, and this effect is greater if a candidate is a voter’s co-partisan. Additionally, voters project their own ideological self-identification onto their candidates: The distance a voter considers themself to be from the ideological center influences, proportionally, how far the voter perceives candidates from either political party to be from the center. I examine the relationship between these effects and electoral outcomes to find limited evidence that voters practice proximity voting generally, with only small vote share penalties for candidates who are distant from the mean voter, but I find an effect of misperception of candidate ideology in the outcome of those elections in which better informed voters are less likely to vote for more extreme candidates. The heterogeneity of misperception and the projection of one’s own ideology onto candidates are previously unexplored, but not inconsistent effects on the conception of the electoral blind spot. In voter perceptions of moderation and the combined effect of misperception and candidate proximity, I find evidence consistent with the presence of an electoral blind spot as a set of policies or candidate positions over which the voter is indifferent.

        Cover page: Looking for an Electoral Blind Spot: The Effects of Information and Partisanship on Perceptions of Candidates’ Ideology and on Electoral Outcomes
        • Article
        • Peer Reviewed
        UCLA Previously Published Works (2021)
        Avoidant behavior is a defining feature of pediatric anxiety disorders. Although prior research has examined it from the perspective of early information processing events, there has been relatively less consideration of the processes by which anxious youth make avoidant decisions and how these choices are reinforced over time. Studies of risk taking are valuable in this regard because they consider how individuals identify the pros and cons of their choices, how they weigh potential gains and losses and estimate their respective probabilities, and how they tolerate the uncertainty intrinsic to any decision. In this review, we place risk taking within existing models of information processing in pediatric anxiety disorders and highlight the particular value of this construct for informing models of developmental psychopathology and individual differences in outcome over time. We review existing behavioral and neurobiological studies of risk taking in anxious youth and conclude by identifying directions for future research.
          Cover page: Brain and Behavior Correlates of Risk Taking in Pediatric Anxiety Disorders
          • Article
          • Peer Reviewed
          UCLA Previously Published Works (2021)
          Nearly a year into the COVID-19 pandemic, conversations about the impact of COVID-19 on children and families have shifted. Initial advice for parents stressed topics such as how to talk about the pandemic with children or cope with illness-related distress. They now focus on youth adjustment to a heavily disrupted school year and on strategies for building long-term resilience. Although these conversations often center on youth adjustment, they have-at last-started to consider the well-being of parents (and other caregivers) as well. This shift in focus is crucial given the enormous challenges that parents face right now and the direct links between their well-being and that of their children. What continues to lag, even well into the pandemic, however, is the provision of workable solutions for addressing parents' mental health. While we applaud the renewed focus on parenting stress and well-being, we remain deeply concerned by the absence of a plan for intervening.
            Cover page: The Parents Are Not Alright: A Call for Caregiver Mental Health Screening During the COVID-19 Pandemic
            • Article
            • Peer Reviewed
            UCLA Previously Published Works (2015)
            Levels of parental expressed emotion (EE) are prospectively associated with the symptomatic course of a range of childhood psychiatric disorders. This article reviews the literature linking parental EE to youth psychopathology and proposes a novel framework for understanding its mechanisms of action. We find that, despite noteworthy methodological limitations, parental EE is linked consistently to a more deleterious course of mood, anxiety, and psychotic disorders in youth. Its mechanism of action is unknown. Models of "toxic family stress" (referring to frequent, sustained, and uncontrollable stress without protective influences) provide one framework for understanding how high EE environments interact with individual biological vulnerabilities to promote illness onset and recurrence. Research aimed at understanding biological responses (e.g., stress reactivity, arousal) to familial EE is needed. Such work may inform efforts to understand how EE affects the course of psychiatric disorders and may guide the development of novel interventions emphasizing emotion regulation strategies.
              Cover page: Parental Expressed Emotion and Youth Psychopathology: New Directions for an Old Construct
              • Article
              Proceedings of the Vertebrate Pest Conference, Volume 15 (1992)
              In Europe, starlings are widely distributed and comprise both resident and migrant populations. These cause various kinds of damage which varies with the crops grown in different European Economic Community (EEC) countries. Although EEC member states are governed by the same legislation on bird protection, each state interprets the Community legislation in its own national legislation. This leads to different national approaches to the prevention of starling damage, with little information exchange between member states. The establishment of an EEC (or wider) working group on bird pests is recommended to coordinate research and development.
                Cover page: The starling in Europe: Multiple approaches to a problem species
                • Article
                • Peer Reviewed
                UCLA Previously Published Works (2017)
                Prior research has identified OCD subtypes or "clusters" of symptoms that differentially relate to clinical features of the disorder. Given the high comorbidity between OCD and anxiety, OCD symptom clusters may more broadly associate with fear and/or distress internalizing constructs. This study examines fear and distress dimensions, including physical concerns (fear), separation anxiety (fear), perfectionism (distress), and anxious coping (distress), as predictors of previously empirically-derived OCD symptom clusters in a sample of 215 youth diagnosed with primary OCD (ages 7-17, mean age = 12.25). Self-reported separation fears predicted membership in Cluster 1 (aggressive, sexual, religious, somatic obsessions, and checking compulsions) while somatic/autonomic fears predicted membership in Cluster 2 (symmetry obsessions and ordering, counting, repeating compulsions). Results highlight the diversity of pediatric OCD symptoms and their differential association with fear, suggesting the need to carefully assess both OCD and global fear constructs that might be directly targeted in treatment.
                  Cover page: Distinguishing Fear Versus Distress Symptomatology in Pediatric OCD
                  • Article
                  • Peer Reviewed
                  UC Irvine Previously Published Works (2012)
                  Methane (CH(4)) flux from ecosystems is driven by C(1)-cycling microorganisms - the methanogens and the methylotrophs. Little is understood about what regulates these communities, complicating predictions about how global change drivers such as nitrogen enrichment will affect methane cycling. Using a nitrogen addition gradient experiment in three Southern California salt marshes, we show that sediment CH(4) flux increased linearly with increasing nitrogen addition (1.23 μg CH(4) m(-2) day(-1) for each g N m(-2) year(-1) applied) after 7 months of fertilization. To test the reason behind this increased CH(4) flux, we conducted a microcosm experiment altering both nitrogen and carbon availability under aerobic and anaerobic conditions. Methanogenesis appeared to be both nitrogen and carbon (acetate) limited. N and C each increased methanogenesis by 18%, and together by 44%. In contrast, methanotrophy was stimulated by carbon (methane) addition (830%), but was unchanged by nitrogen addition. Sequence analysis of the sediment methylotroph community with the methanol dehydrogenase gene (mxaF) revealed three distinct clades that fall outside of known lineages. However, in agreement with the microcosm results, methylotroph abundance (assayed by qPCR) and composition (assayed by terminal restriction fragment length polymorphism analysis) did not vary across the experimental nitrogen gradient in the field. Together, these results suggest that nitrogen enrichment to salt marsh sediments increases methane flux by stimulating the methanogen community.
                    Cover page: The Effect of Nitrogen Enrichment on C1-Cycling Microorganisms and Methane Flux in Salt Marsh Sediments
                    • Article
                    • Peer Reviewed
                    UC San Francisco Previously Published Works (2018)
                    Introduction  Large and even moderate sized, extra-axial cerebellopontine angle (CPA) tumors may fill this restricted space and distort the regional anatomy. It may be difficult to determine even with high resolution magnetic resonance imaging (MRI) if the tumor is dural-based, or what the nerve of origin is if a schwannoma. While clinical history and exam are helpful, they are not unequivocal, particularly since many patients present with a myriad of symptoms, or conversely an incidental finding. We present an atypical appearing, asymptomatic CPA tumor, ultimately identified at surgery to be a trigeminal schwannoma. Case History  A 40-year-old man presented with new-onset seizure. MRI identified an incidental heterogeneously contrast-enhancing CPA lesion ( Fig. 1A - D ). The tumor was centered on the internal auditory canal (IAC) with no tumor extension into Meckel's cave, IAC or jugular foramen. Audiometry demonstrated 10db of relative left-sided hearing loss with 100% word recognition. Physical examination was negative for focal neurologic deficits. A retrosigmoid craniotomy was performed and an extra-axial, yellow-hued mass was encountered and resected, which was ultimately confirmed to originate from the trigeminal nerve ( Video 1 ). Gross total resection was achieved, and the patient recovered from surgery with partial ipsilateral trigeminal sensory loss and no other new neurologic deficits. Conclusion  Pure CPA trigeminal schwannomas are rare, but should be considered in the differential for enhancing CPA lesions. Although, Meckel's cave involvement is frequently observed, it is not universal, and pure CPA schwannomas of all cranial nerves IV-XII have been reported in the literature. The link to the video can be found at: https://youtu.be/AlodYCu70F8 .
                      Cover page: Trigeminal Nerve Schwannoma of the Cerebellopontine Angle
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