Browsing by Author "Zucker, Nancy"

The autonomic nervous system (ANS) regulates physiological processes throughout the body and disruption or imbalance of that system has been associated with negative physical and psychological outcomes. Pupil responsivity is controlled by the autonomic nervous system and has been show to index activity of the locus coeruleus-norepinephrine (LC-NE) pathway of innervation. Dysregulation of that pathway has been proposed to relate to differences in attentional control in autism. The current study looked at autonomic nervous system functioning in adults on the autism spectrum through the lens of pupil responsivity to tasks probing reactions to changes in environmental lighting and to complex stimuli. The primary aims of the study evaluated the questions: (1) Do measures of pupil response to different types of stimuli yield different results based on autism diagnostic status? and (2) Are there relationships between measures of pupil response, features of autism and self-reported symptoms of depression and anxiety? Pupillometry and symptom measures were conducted with a sample of adults on the autism spectrum (N=11) and adults without a diagnosis of autism (N=14). Primary variables were baseline pupil diameter, amplitude of dilation/constriction, latency to reach maximal dilation/constriction and recovery velocity. Regarding pupil response to environmental lighting, results indicated timing differences of pupillary response over both light and dark conditions based on autism diagnostic status. In particular, adults on the autism spectrum showed longer latency of pupil response to flashes of dark after being accustomed to a light and slower recovery to the accustomed dark condition after being exposed to flashes of light. Regarding tasks evoking pupil responses to complex stimuli (an auditory reversal learning task and an auditory oddball task), results indicated magnitude of response (amplitude) and variability of response differences related to autism diagnostic status. In particular, adults on the autism spectrum showed larger amplitude of response to all trials in the reversal learning task and greater variability of baseline pupil size across trials in the auditory oddball task than adults without a diagnosis of autism. Across tasks evoking pupil response related to environmental lighting or complex stimuli, associations between autism traits—in particular, intense interests/repetitive behaviors, depression, and anxiety—and different pupillometry measures were found in both the autism and non-autism groups. However, these relationships were different for the different groups. The current study explores differences in pupillary light reflex in adults on the autism spectrum and the results support extant findings of individuals on the autism spectrum potentially having an alternate time course of pupil response. The implications these results may have in terms of understanding of ANS functioning, particularly different sympathetic engagement of the LC-NE pathway and differences in attentional control or reward sensitivity, in autism are discussed. Results also suggest that certain features of autism as well as depression and anxiety seem to co-vary with differences in certain pupillometry measure—especially in the context of increased cognitive demands. Limitations of the study, including sample size and measurement issues, are discussed. Overall, the results suggest future research directions, which may increase understanding of relationships between individual behavior and brain functioning across the autism spectrum. These include possible comparisons of pupil response measures to other direct measures of ANS or brain function as well as the need for controlling for additional measures of psychological well-being and reward sensitivity.

There is increased need for mental health support on college campuses: existing campus resources are increasingly unable to meet the mental health needs of their undergraduate communities. There is also increased preference from students for some forms of emotional support to come from peers. Peer support programs, in which students act as supportive listeners towards their fellow students, are increasingly common on college campuses, but the uptake and utility of these programs is not routinely examined. There is also a need to ensure that the mental health of students providing support is protected. Providing support for peers can be a positive source of meaning and life purpose, but also a source of perceived stress, emotional exhaustion, and, potentially, burnout. If such programs are to be developed and disseminated, it is critical to understand the mechanisms whereby communicating with a peer in a moment of distress can improve mental health outcomes. This dissertation aims to address the critical need of identifying key components for sustainability by providing an updated review of the prevalence and nature of existing undergraduate peer support programs (Study 1), synthesizing research on the impact of providing peer mental health support (Study 2), and evaluating the acceptability and feasibility of a novel text-based peer support program with a sample of undergraduates (Study 3). We found that approximately 10% of institutions affiliated with the American College Health Association have a peer program dedicated to supporting student mental health. Moreover, there has been a recent surge of interest in these programs: over 50% of programs identified were founded in the last 10 years. However, there is limited data collection and even less peer-reviewed research on the impact of these programs for the students receiving and providing support. DukeLine, an innovative text-based peer support program, was designed, implemented, and assessed for sustainability. Peer coaches were trained through a for-credit, semester-long course taught within the Department of Psychology and Neuroscience and committed to providing peer support in two-person shifts for two semesters while enrolled in a practicum course with weekly group supervision. No coach reported experiencing significant emotional exhaustion and, on average, coaches report deriving moderate levels of meaning and purpose from their role as a peer coach. Over a quarter (29.73%) of students who reached out to DukeLine for support did so more than once and 88.89% of texters reported feeling extremely satisfied with the support they received. DukeLine offers a sustainable model for peer support programs targeting undergraduate mental health that is acceptable and feasible, for students who seek and provide support.

A key debate in nutrition research is whether highly processed foods uniquely reinforce consumption and if, in being uniquely reinforcing, highly processed foods cause overeating and obesity. To that end, overarching goal of my dissertation was to examine the mechanisms through which food motivates appetitive behavior and how relative differences in these processes predict differences in eating behavior.

Here we cover three studies where participants are asked to make choices to earn food rewards. In each study, we examine how participants form action-reward contingency estimations and reward magnitude estimations through learning and how their choices reflect differences in the underlying decision processes. In chapter two, we show that when you reinforce behavior with a food rather than money, differences in reward magnitude estimation predict differences in behavior. Our results demonstrate that a key feature of natural reinforcers like food – that reward magnitude diminishes as a function of consumption due to changes in internal state – is observable in participants’ decision-making. In chapter three, we find that a large subset of children, whose choices appear as if they are trying to lose, were using a choice strategy that would be nearly optimal given a plausible (albeit false) assumption about the experimental environment. Our results indicate that children can form computationally complex models of their environment; however, their choices can be maladaptive if those models are incorrect. In chapter four, we examined how individual differences in action-reward contingency estimation and estimated reward magnitude for food rewards predicted differences on validated clinical measures associated with weight gain in children. We show preliminary evidence that overall reward magnitude for snack foods, as well as change in reward magnitude, are associated with outcomes on the Child Eating Behavior Questionnaire and the Eating in the Absence of Hunger Task.

Taken together, our results demonstrate that highly processed foods could affect how people make reward magnitude estimations and ultimately make decisions about what and how much to eat. However, the extent to which decision processes affect clinical outcomes like risk for weight gain is unclear. We show that while differences in reward magnitude estimation may not affect cognitive processes underlying the choice of when to stop eating, it may affect choices about portion. Highly processed foods could meaningfully affect portion size selection by altering expectations about how consumption affects internal state. Given the strong association between portion sizes and overall consumption, this suggests a that highly processed foods could trigger meaningful differences in caloric intake by changing what and how much people put on their plates.

Anorexia nervosa (AN) is a dangerous disorder characterized by unrelenting rigidity that continues even in the presence of deadly outcomes. Despite this, our understanding of factors that promote and maintain rigidity is lacking. The current paper proposes a model suggesting that rigid behaviors in AN can be formulated as maladaptive rule-governed behavior that emerges in contexts of uncertainty and loss of control, such as in the presence of affective arousal. An empirical study examining the differences between individuals weight recovered from AN (AN-WR) and healthy controls (CN) on parameters of rule-governed behavior in neutral and stressful contexts is described. Seventy-four adults (AN-WR: 36; CN: 38) were randomized to undergo either a stressful or neutral mood manipulation and then completed a laboratory assessment of rule-governed behavior, along with questionnaires measuring difficulties with uncertainty. While the AN-WR group demonstrated greater flexibility in rule implementation compared to the CN group, they evidenced greater impairment in behavioral extinction. Furthermore, although affective arousal did not significantly impact rule-governed behavior as expected, difficulties tolerating uncertainty were significantly related to rule-governed outcomes exclusively in the AN-WR group. Taken together, findings provide preliminary support for maladaptive rule-governed behavior in AN and suggest that this is related to an intolerance of uncertainty. Findings and treatment implications are discussed in light of study limitations.

Binge and loss of control (LOC) eating are clinically significant symptoms that constitute syndromes characterized by a repetitive pattern of maladaptive and subjectively uncontrollable binge or loss of control eating. The hippocampal-dependent memory system appears to play an important role in the regulation of food intake in studies employing animal models. These findings may extend to humans, but research has been limited, particularly among vulnerable populations, such as those with eating pathology. Existing research suggests excessive energy intake and/or consumption of high fat, high sugar foods impairs performance on hippocampal-dependent learning and memory tasks, which in turn, is associated with excessive food intake and motivated high fat, high sugar food seeking behaviors. This vicious cycle may be particularly relevant to individuals with binge or loss of control eating, as persistent binge/LOC eating episodes are associated with several food intake patterns and individual difference factors that may strengthen the observed associations.

This study sought to examine the potential role of learning and memory in the development and maintenance of binge and LOC eating behaviors among a community sample of (N=66) young adult women, who either endorsed binge or LOC eating (n=35) or reported typical eating behaviors (n=31). Participants completed clinical diagnostic interviews, standardized neuropsychological measures of cognitive ability and hippocampal-dependent memory, self-report measures of eating behaviors, dietary intake of highly palatable foods, depressive symptoms, psychological functioning, autobiographical memory (general and eating event memories), and current mood state and hunger. Results revealed that participants who endorsed binge or loss of control eating performed worse on several measures of hippocampal-dependent memory, including measures of visuo-spatial learning and memory, verbal learning and memory, immediate memory, and delayed memory. Findings from the autobiographical memory tasks did not support our hypothesis, but provided insight into other factors, such as the potential role of emotion, in the study of autobiographical memory and LOC eating. The current study also did not find evidence to support the predictive utility of high fat, high sugar dietary intake on differences in hippocampal functioning, at least as measured in the current sample. Future research should continue to characterize and probe hippocampal-dependent memory among those with LOC eating, and explore possible differences in the visuo-spatial learning and memory system. Future research should also seek to overcome some of the methodological challenges in measuring dietary intake of high fat, high sugar foods, to further our understanding of the vicious cycle, especially among vulnerable populations.

Inadequate nutrition has been shown to adversely impact brain development and cognitive functioning (Pollitt, Lewis, Garza, & Shulman, 1983). Unhealthy eating practices are frequently formed in college-aged samples; individuals in this age-range may be at risk for developing dangerous dieting behaviors (Neumark-Sztainer, Butler, & Palti, 1995). Studies examining the acute impact of eating regular meals on cognition have reported inconsistent findings, necessitating the exploration of moderators to possibly help explain findings. This study sought to clarify the impact of skipping lunch on cognitive ability and interoceptive awareness in college-aged students by including eating restraint as a moderator. Participants were randomized to a ‘lunch’ condition (consuming a 638-calorie shake) or a ‘lunch omission’ condition (consuming a 48-calorie shake). Prior to shake consumption, participants completed demographic questionnaires and reported levels of affect, satiety and fatigue. After a controlled wait period of two hours, participants completed a neuropsychology battery, which assessed short-term memory , long-term memory, working memory, attention, processing speed, set shifting, eating disorder symptomology, depression, and anxiety.

Results revealed that participants in the lunch condition had better short-term memory performance relative to participants in the lunch omission condition. No differences were found between groups for long-term memory, working memory, attention, or processing speed. Regressing set shifting speed on the manipulation, eating restraint scores, and their interaction revealed a trending interaction term: Individuals in the no-lunch condition had faster set shifting speed than individuals in the lunch-condition, but only for those with lower levels of eating restraint. Lastly, regressing change in satiety on the manipulation, eating restraint scores, and their interaction, revealed a significant interaction term: Individuals in the lunch condition reported higher satiety than individuals in the no lunch-condition, but only for those with lower levels of eating restraint. There was no evidence to support differences in affect or fatigue between conditions. Implications of these findings, limitations to consider, and future research directions are discussed in the body of the paper.

Inadequate nutrition has been shown to adversely impact brain development and cognitive functioning (Pollitt, Lewis, Garza, & Shulman, 1983). Unhealthy eating practices are frequently formed in college-aged samples; individuals in this age-range may be at risk for developing dangerous dieting behaviors (Neumark-Sztainer, Butler, & Palti, 1995). Studies examining the acute impact of eating regular meals on cognition have reported inconsistent findings, necessitating the exploration of moderators to possibly help explain findings. This study sought to clarify the impact of skipping lunch on cognitive ability and interoceptive awareness in college-aged students by including eating restraint as a moderator. Participants were randomized to a ‘lunch’ condition (consuming a 638-calorie shake) or a ‘lunch omission’ condition (consuming a 48-calorie shake). Prior to shake consumption, participants completed demographic questionnaires and reported levels of affect, satiety and fatigue. After a controlled wait period of two hours, participants completed a neuropsychology battery, which assessed short-term memory , long-term memory, working memory, attention, processing speed, set shifting, eating disorder symptomology, depression, and anxiety.

Results revealed that participants in the lunch condition had better short-term memory performance relative to participants in the lunch omission condition. No differences were found between groups for long-term memory, working memory, attention, or processing speed. Regressing set shifting speed on the manipulation, eating restraint scores, and their interaction revealed a trending interaction term: Individuals in the no-lunch condition had faster set shifting speed than individuals in the lunch-condition, but only for those with lower levels of eating restraint. Lastly, regressing change in satiety on the manipulation, eating restraint scores, and their interaction, revealed a significant interaction term: Individuals in the lunch condition reported higher satiety than individuals in the no lunch-condition, but only for those with lower levels of eating restraint. There was no evidence to support differences in affect or fatigue between conditions. Implications of these findings, limitations to consider, and future research directions are discussed in the body of the paper.

Functional abdominal pain (FAP) is a commonly occurring gastrointestinal disorder in children and adolescents. It is associated with significant distress and impairment for both children and caregivers. Psychosocial treatments have been shown to effectively treat FAP and related outcomes. However, not all children respond to treatment. Using data from a randomized controlled trial for childhood FAP, the present study aimed to clarify what factors predicted treatment non-response, how and for whom treatments worked, and why some children’s pain worsened. Participants were randomized to undergo one of two 10-week interventions—either caregiver education or a novel, acceptance- and interoceptive exposure-based intervention. They completed pain diaries and interviews assessing both child and caregiver report of the intensity, frequency, and duration of their pain; questionnaires about therapeutic alliance, somatic sensitivities, and psychological factors; and interviews about coping strategies and treatment at various time points before, during, and after treatment.Results revealed that higher levels of baseline anxiety sensitivity were associated with lower probability of treatment response to the caregiver education intervention but not the novel intervention. Anxiety and depressive symptoms emerged as marginally significant predictors of changes in functional impairment across both treatment arms. In-depth examination of quantitative and qualitative data for children whose pain worsened suggested that neither their pain nor related impairment were at clinically significant levels following intervention, despite statistical significance. Study implications, limitations, and directions for future research are discussed.