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Scholarly Works (7 results)

  • Thesis
  • Peer Reviewed
UCLA Electronic Theses and Dissertations (2021)

Internalizing symptoms and disorders – such as anxiety and depression – increase in adolescence (Meyer and Lee, 2019) and can interact with youth brain and behavioral development. As youth develop, changing biological and environmental factors necessitate developing novel skills, such as emotion regulation and reward-based learning strategies, while balancing new drives toward risk-taking. Given how complex and in-flux this period of life is, investigating the role of internalizing symptoms in a variety of adolescent behaviors is crucial for better understanding how to support youth through this dynamic developmental stage. The studies in this dissertation examine how internalizing symptoms relate to brain development – specifically, functional connectivity and activity associated with emotion regulation and reward learning – as well as risk-taking in the real world. Chapter 1 provides a general introduction to the research outlined in the following chapters. Chapter 2 describes research relating internalizing symptomatology in subclinical youth to amygdala-whole brain functional connectivity. Findings demonstrate that the relationship between internalizing symptoms and amygdala connectivity is stronger in girls than boys, and that youth generally demonstrate greater connectivity between the amygdala and regions associated with emotional processing as a function of greater internalizing symptoms. In Chapter 3, findings from the first study to investigate brain and behavioral differences in emotion regulation between youth with and without anxiety are presented. Youth with anxiety regulated their emotions to the same extent as non-anxious peers; however, regulation may have been especially effortful for youth with anxiety as they demonstrated stronger prefrontal cortex activation and connectivity with the amygdala during regulation. Research presented in Chapter 4 characterizes the relationship between anxiety severity and reward learning in a subclinical sample. While all youth were capable of learning stimulus-reward associations, youth with higher anxiety allocated value toward non-rewarding stimuli to a greater extent and showed a stronger relationship between brain activity and behavior; furthermore, within this group, those with the highest intolerance of uncertainty showed the least reward network activation when receiving rewards. Finally, Chapter 5 examines racial disparities in the juvenile justice system, as well as tracks the longitudinal change in internalizing symptoms alongside criminal offending. Black youth, and to a slightly lesser extent Latino youth, faced the greatest disparities through system processing. All youth demonstrated greater improvements in internalizing symptoms alongside decreased offending, showing the tight relationship between mental health and criminal offending. Taken together, results from this dissertation demonstrate the varied effects of internalizing symptoms on adolescent brain and behavioral development. As such, these studies present a multi-disciplinary look at the role of mental health in the lives of adolescents.

    Cover page: Brain and Behavioral Correlates of Internalizing Symptoms in Adolescence
    • Article
    • Peer Reviewed
    UC San Francisco Previously Published Works (2019)
    The exponential rise in use of mobile consumer electronics has presented a great potential for research to be conducted remotely, with participants numbering several orders of magnitude greater than a typical research paradigm. Here, we attempt to demonstrate the validity and reliability of using a consumer game-engine to create software presented on a mobile tablet to assess sensorimotor synchronization, a proxy of rhythmic ability. Our goal was to ascertain whether previously observed research results can be replicated, rather than assess whether a mobile tablet achieves comparable performance to a desktop computer. To achieve this, younger (aged 18-35 years) and older (aged 60-80 years) adult musicians and non-musicians were recruited to play a custom-designed sensorimotor synchronization assessment on a mobile tablet in a controlled laboratory environment. To assess reliability, participants performed the assessment twice, separated by a week, and an intra-class correlation coefficient (ICC) was calculated. Results supported the validity of this approach to assessing rhythmic abilities by replicating previously observed results. Specifically, musicians performed better than non-musicians, and younger adults performed better than older adults. Participants also performed best when the tempo was in the range of previously-identified preferred tempos, when the stimuli included both audio and visual information, and when synchronizing on-beat compared to off-beat or continuation (self-paced) synchronization. Additionally, high ICC values (>0.75) suggested excellent test-retest reliability. Together, these results support the notion that consumer electronics running software built with a game engine may serve as a valuable resource for remote, mobile-based data collection of rhythmic abilities.
      Cover page: A Tablet-Based Assessment of Rhythmic Ability
      • Article
      • Peer Reviewed
      UC Riverside Previously Published Works (2017)
      Older adults, compared to younger adults, do not benefit from predictive information regarding either what type of stimuli they will see or when to expect them, yet it is unclear whether older adults benefit when given both types of predictive information. Here, electroencephalogram recordings of older (aged 62-87 years) and younger (aged 20-32 years) adults were recorded during a working memory task. Each trial contained 2 faces and 2 scenes presented sequentially, followed by a 5-second delay and a probe stimulus. Participants were told what stimuli to remember/ignore and when they would appear. Predictive cues enabled older adults to remember stimuli as accurately as younger adults, although response times were significantly slower, even when corrected for general age-related slowing. Previously observed reductions in P1/N1 amplitude and latency suppression to irrelevant stimuli were not seen. Rather, older adults exhibited lowered P3 amplitudes to relevant stimuli; those with the greatest declines yielded the lowest accuracy and slowest response times. This shows that predictive information can help maintain accuracy, although not response times, which correspond to age-related declines in neural enhancement to relevant stimuli.
        Cover page: Predictive cues and age-related declines in working memory performance
        • Article
        • Peer Reviewed
        UCLA Previously Published Works (2023)
        Youth in the juvenile justice system evince high rates of mental health symptoms, including anxiety and depression. How these symptom profiles change after first contact with the justice system and - importantly - how they are related to re-offending remains unclear. Here, we use latent growth curve modeling to characterize univariate and multivariate growth of anxiety, depression, and re-offending in 1216 male adolescents over 5 years following their first arrest. Overall, the group showed significant linear and quadratic growth in internalizing symptoms and offending behaviors over time such that levels decreased initially after first arrest followed by a small but significant upturn occurring a few years later. Crucially, multivariate growth models revealed strong positive relationships between the rates of growth in internalizing symptoms and offending behaviors such that improvements in mental health related to greater decreases in offending, and vice versa. These results highlight the reciprocal nature of internalizing and externalizing problems in adolescence, underscoring the importance of considering mental health alongside offending in the juvenile justice system.
          Cover page: Characterizing trajectories of anxiety, depression, and criminal offending in male adolescents over the 5 years following their first arrest.
          • Article
          • Peer Reviewed
          UCLA Previously Published Works (2021)
          Minority youth are disproportionately represented in the juvenile justice system. Examining how racial disparities relate to biased entry into and continued involvement with the system, while accounting for past and current offending, can provide context about the mechanisms behind overrepresentation. 1,216 adolescents were examined after first arrest to explore associations between race and history of self-reported offending, likelihood of formal processing, and likelihood of rearrest. Black youth committed fewer offenses prior to arrest than White youth, Black and Latino youth were more likely to be formally processed, and Black youth were most likely to be rearrested (even controlling for postbaseline offending), highlighting that minority youth are overrepresented in the juvenile justice system despite similar or lower levels of criminal behavior.
            Cover page: Exploring Disproportionate Minority Contact in the Juvenile Justice System Over the Year Following First Arrest.
            • Article
            • Peer Reviewed
            UCLA Previously Published Works (2020)
            Autism spectrum disorder (ASD) is associated with the altered functional connectivity of 3 neurocognitive networks that are hypothesized to be central to the symptomatology of ASD: the salience network (SN), default mode network (DMN), and central executive network (CEN). Due to the considerably higher prevalence of ASD in males, however, previous studies examining these networks in ASD have used primarily male samples. It is thus unknown how these networks may be differentially impacted among females with ASD compared to males with ASD, and how such differences may compare to those observed in neurotypical individuals. Here, we investigated the functional connectivity of the SN, DMN, and CEN in a large, well-matched sample of girls and boys with and without ASD (169 youth, ages 8-17). Girls with ASD displayed greater functional connectivity between the DMN and CEN than boys with ASD, whereas typically developing girls and boys differed in SN functional connectivity only. Together, these results demonstrate that youth with ASD exhibit altered sex differences in these networks relative to what is observed in typical development, and highlight the importance of considering sex-related biological factors and participant sex when characterizing the neural mechanisms underlying ASD.
              Cover page: Sex Differences in Functional Connectivity of the Salience, Default Mode, and Central Executive Networks in Youth with ASD
              • Article
              • Peer Reviewed
              UCLA Previously Published Works (2022)
              The biological mechanisms underlying the greater prevalence of autism spectrum disorder in males than females remain poorly understood. One hypothesis posits that this female protective effect arises from genetic load for autism spectrum disorder differentially impacting male and female brains. To test this hypothesis, we investigated the impact of cumulative genetic risk for autism spectrum disorder on functional brain connectivity in a balanced sample of boys and girls with autism spectrum disorder and typically developing boys and girls (127 youth, ages 8-17). Brain connectivity analyses focused on the salience network, a core intrinsic functional connectivity network which has previously been implicated in autism spectrum disorder. The effects of polygenic risk on salience network functional connectivity were significantly modulated by participant sex, with genetic load for autism spectrum disorder influencing functional connectivity in boys with and without autism spectrum disorder but not girls. These findings support the hypothesis that autism spectrum disorder risk genes interact with sex differential processes, thereby contributing to the male bias in autism prevalence and proposing an underlying neurobiological mechanism for the female protective effect.
                Cover page: Impact of autism genetic risk on brain connectivity: a mechanism for the female protective effect.
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