Biology Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2749
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Item Predictors of Peer Interaction Success for Autistic and Non-Autistic Youth(2024) McNaughton, Kathryn; Redcay, Elizabeth; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Successful peer interactions are a crucial component of mental health and well-being for autistic and non-autistic youth. Factors that influence successful peer interactions are particularly relevant to investigate in middle childhood and adolescence, a developmental period in which peer interactions take on increased importance for mental health. Research into social interactions can involve both individual-level and interindividual-level understanding of interaction outcomes. Individual-level predictors can yield insight into the way one’s own characteristics predict social interaction outcomes, for example, informing theories about how an individual’s social motivation may predict their social enjoyment. However, because research into social interaction challenges and success in autism has historically focused on individual-level contributions of autistic individuals to social interaction outcomes, it is also important to understand interindividual-level mechanisms, such as the similarity or synchrony between individuals, to understand the role both non-autistic and autistic individuals play in shaping social interactions and their outcomes. Therefore, the overarching goal of this dissertation is to evaluate potential neural and behavioral predictors of peer interaction success in autistic and non-autistic youth during middle childhood and adolescence at the individual and interindividual level. First, I demonstrate that neural sensitivity to social-interactive reward is an individual-level predictor of peer interaction enjoyment. Next, I move beyond individual-level neural predictors to interindividual-level neural predictors, providing evidence for how neural similarity to peers may differentially relate to day-to-day interaction success across different interaction types, such as interactions with peers. Finally, I establish smiling synchronization as an interindividual predictor of peer interaction enjoyment. These studies span the neural and behavioral levels of analysis, providing insight into how these levels of analysis can be investigated from both an individual and interindividual perspective. The findings advance understanding of factors that predict peer interaction success, leading to better understanding of opportunities to support successful peer interactions through individual and interindividual interventions with autistic and non-autistic youth.Item BRAIN BASIS OF HUMAN SOCIAL INTERACTION: NEUROCOGNITIVE FUNCTIONS AND META-ANALYSIS(2023) Merchant, Junaid Salim; Redcay, Elizabeth; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Social interactions, or the reciprocal exchange between socially engaged individuals, plays a central role in shaping human life. Social interactions are fundamental for neurocognitive development, and a key factor contributing to mental and physical health. Despite their importance, research investigating the neurocognitive systems associated with human social interaction is relatively new. Human neuroimaging research has traditionally used approaches that separate the individual from social contexts, thereby limiting the ability to examine brain systems underlying interactive social behavior. More recent work has begun incorporating real-time social contexts, and have implicated an extended network of brain regions associated with social interaction. However, open questions remain about the neurocognitive processes that are critical for social interactions and the brain systems that are commonly engaged. The current dissertation aims to address these gaps in our understanding through a set of studies using computational and data-driven approaches. Study 1 examined the relationship between social interaction and mentalizing, which is the ability to infer the mental states of others that is considered to be critically important for social interactions. Prior work has demonstrated that mentalizing and social interaction elicit brain activity spatially overlapping areas, but spatial overlap is not necessarily indicative of a common underlying process. Thus, Study 1 utilized multivariate approaches to examine the similarity of brain activity patterns associated with mentalizing outside of social contexts and when interacting with a peer (regardless of mentalizing) as a means for inferring a functional relationship between the two. Study 2 investigated brain regions commonly engaged across social interactive contexts using coordinate-based meta-analysis, which is an approach for aggregating findings across neuroimaging literature. This involved an exhaustive search strategy to find fMRI and PET studies that utilize social interactive approaches, and calculated spatial convergence across studies as a means to uncover brain regions that are reliably implicated during social interaction. The results from Studies 1 and 2 offer major advancements for a neuroscientific understanding of social interaction by demonstrating a functional link with mentalizing and through elucidating brain systems that are commonly reported in studies using social interactive approaches.Item THE ROLE OF THEORY OF MIND IN SOCIAL INTERACTION(2021) Alkire, Diana; Redcay, Elizabeth; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Theory of mind (ToM) is assumed to be instrumental to social interactions, yet it is typically studied using non-interactive laboratory tasks. Standard measures are thus limited in their ability to characterize the cognitive and neural substrates of ToM in naturalistic social interactions, as well as the mechanisms explaining social-interactive difficulties in autism spectrum disorder (ASD). Across three studies, this dissertation aimed to highlight and bridge the disconnect between the study of ToM and its real-world implementation. Study 1 assessed the relative importance of a range of social-cognitive, social-perceptual, and social-affective constructs in explaining variance in the social symptoms of ASD. Three standard, non-interactive ToM measures together explained only 6% of the variance in social symptoms, reinforcing the need for interactive approaches to studying ToM. Study 2 applied such an approach using a socially interactive neuroimaging paradigm to measure brain activation associated with both ToM and social interaction. In typically developing children aged 8-12, interacting with a peer, even in the absence of explicit ToM demands, engaged many of the same regions as did non-interactive ToM reasoning, consistent with the idea that social interaction elicits spontaneous ToM-related processes. Study 3 also investigated ToM in social interaction, this time at the behavioral level, by introducing a novel observational coding system that measures the use of (or failure to use) ToM in naturalistic conversation. Among dyads of typically developing and autistic children and adolescents, conversational ToM (cToM) did not predict interaction success. However, the cToM Negative subscale—capturing ToM-related violations of conversational norms—was negatively associated with two forms of non-interactive ToM: 1) recognizing complex emotions from facial expressions, and 2) spontaneously attributing mental states when describing abstract social animations. Furthermore, exploratory analyses revealed associations between cToM and brain activation during the socially interactive neuroimaging task used in Study 2. Findings across the three studies highlight the multifaceted nature of the ToM construct, the value of socially interactive approaches to studying ToM, and the importance of considering ToM alongside other social-cognitive and affective processes when investigating social interaction.Item The neural bases of the bilingual advantage in cognitive control: An investigation of conflict adaptation phenomena.(2014) Teubner-Rhodes, Susan; Dougherty, Michael; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The present dissertation examines the effects of bilingualism on cognitive control, the ability to regulate attention, particularly in the face of multiple, competing sources of information. Across four experiments, I assess the conflict monitoring theory of the so-called "bilingual advantage", which states that bilinguals are better than monolinguals at detecting conflict between multiple sources of information and flexibly recruiting cognitive control to resolve such competition. In Experiment 1, I show that conflict adaptation, the phenomenon that individuals get better at resolving conflict immediately after encountering conflict, occurs across domains, a pre-requisite to determining whether bilingualism can improve conflict monitoring on non-linguistic tasks. Experiments 2 and 3 compare behavioral and neural conflict adaptation effects in bilinguals and monolinguals. I find that bilinguals are more accurate at detecting initial conflicts and show corresponding increases in activation in neural regions implicated in language-switching. Finally, Experiment 4 extends the bilingual advantage in conflict monitoring to syntactic ambiguity resolution and recognition memory.Item The Neural Mechanisms Supporting Structure and Inter-Brain Connectivity In Natural Conversation(2014) AbdulSabur, Nuria; Idsardi, William; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Conversation is the height of human communication and social interaction, yet little is known about the neural mechanisms supporting it. To date, there have been no ecologically valid neuroimaging studies of conversation, and for good reason. Until recently, imaging techniques were hindered by artifact related to speech production. Now that we can circumvent this problem, I attempt to uncover the neural correlates of multiple aspects of conversation, including coordinating speaker change, the effect of conversation type (e.g. cooperative or argumentative) on inter-brain coupling, and the relationship between this coupling and social coherence. Pairs of individuals underwent simultaneous fMRI brain scans while they engaged in a series of unscripted conversations, for a total of 40 pairs (80 individuals). The first two studies in this dissertation lay a foundation by outlining brain regions supporting comprehension and production in both narrative and conversation - two aspects of discourse level communication. The subsequent studies focus on two unique features of conversation: alternating turns-at-talk and establishing inter-brain coherence through speech. The results show that at the moment of speaker change, both people are engaging attentional and mentalizing systems - which likely support orienting toward implicit cues signaling speaker change as well as anticipating the other person's intention to either begin or end his turn. Four networks were identified that are significantly predicted by a novel measure of social coherence; they include the posterior parietal cortex, medial prefrontal cortex, and right angular gyrus. Taken together, the findings reveal that natural conversation relies on multiple cognitive networks besides language to coordinate or enhance social interaction.Item WORKING MEMORY ASSESSMENT AND TRAINING(2011) Atkins, Sharona M.; Dougherty, Michael R; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Working memory, the ability to maintain and manipulate information, is a core cognitive function important for everyday life. The capacity of working-memory differs across individuals, with working-memory capacity a reliable predictor of general fluid intelligence, verbal and mathematical abilities, and classroom achievement. However, research has been inconclusive on whether working-memory is a unitary domain-general construct, or multi-component domain-specific construct. Most theories had until recently thought that working-memory was a fixed ability; however, recent research suggests that working-memory is malleable and can be improved through cognitive training. These training-induced improvements have also been shown on untrained cognitive tasks, such as general fluid intelligence, attention, reading, and math. My research examines the structure of working-memory, validates newly designed web-administered working-memory assessments, and investigates the malleability of domain specific working-memory training.