Browsing by Department "Psychology and Neuroscience"

"Cognitive control" describes endogenous guidance of behavior in situations where routine stimulus-response associations are suboptimal for achieving a desired goal. The computational and neural mechanisms underlying this capacity remain poorly understood. The present dissertation examines recent advances stemming from the application of a statistical, Bayesian learner perspective on control processes. An important limitation in current models consists of a lack of a plausible mechanism for the flexible adjustment of control over variable environments. I propose that flexible cognitive control can be achieved by a Bayesian model with a self-adapting, volatility-driven learning scheme, which modulates dynamically the relative dependence on recent (short-term) and remote (long-term) experiences in its prediction of future control demand. Using simulation data, human behavioral data and human brain imaging data, I demonstrate that this Bayesian model does not only account for several classic behavioral phenomena observed from the cognitive control literature, but also facilitates a principled, model-guided investigation of the neural substrates underlying the flexible adjustment of cognitive control. Based on the results, I conclude that the proposed Bayesian model provides a feasible solution for modeling the flexible adjustment of cognitive control.

Based on a biopsychosocial model of mammography pain, the current study assessed if specific biological and psychosocial factors were associated with higher reported mammography pain in early stage breast cancer survivors. One hundred and twenty-seven women completed questionnaires assessing demographic information, cancer treatment history, ongoing breast pain, mammography-related anxiety, and social support immediately prior to receiving a mammogram. They then completed questionnaires assessing mammography pain and mammography-related pain catastrophizing immediately following the mammogram. Using path modeling and mediation analyses, relations among these variables were examined. Results revealed that mammography-related pain catastrophizing was related to higher mammography pain directly, while ongoing breast pain, lower social support quantity, and lower perceived quality of social support related to higher mammography pain indirectly through mammography-related pain catastrophizing. Moderated mediation analyses found that the mediation effects of mammography-related pain catastrophizing were significantly different at varying levels of perceived quality of social support, with more pronounced negative effects for those with higher quality support than those with lower quality support. The theoretical, clinical, and research implications of these findings are discussed.

Controlled breathing techniques are widely used to help people manage pain, and there is growing interest in using these approaches during painful outpatient medical procedures. The outpatient MRI-guided breast biopsy is one setting where patients may particularly benefit from breathing interventions for pain. To date, however, no studies have examined interventions for pain reduction in this setting. This randomized controlled pilot study assessed the feasibility, acceptability, and efficacy of a novel audio-recorded controlled breathing intervention for reducing breast and body pain in women undergoing MRI-guided breast biopsy. Fifty-eight women undergoing MRI-guided breast biopsy were randomized to a 1) controlled breathing intervention or 2) usual care condition. Assessments of pain, anxiety, distraction from pain, relaxation, blood pressure, heart rate, pain catastrophizing, and self-efficacy for managing pain and anxiety were administered. Participants were assessed at baseline, during biopsy, immediately post-biopsy, and 24 hours post-biopsy. Results demonstrated that the intervention was feasible and acceptable. However, when compared to usual care, controlled breathing did not significantly reduce pain, increase distraction from pain or relaxation during biopsy, decrease physiological reactivity, reduce pain catastrophizing, or increase self-efficacy for pain and anxiety from pre- to post-biopsy. These findings could be used to revise the controlled breathing intervention.

Friendship has consistently been found to act as a buffer against psychological maladjustment for healthy youth and youth experiencing difficulties including parental divorce and natural disasters. Less known is the role of friendship may have for females coping with a chronic health problem. Therefore, the objective of the current study was to evaluate the health factors and friendship precursors that may influence friendship, and in turn, how those friendships may predict psychosocial adjustment. A sample of chronically ill females (N = 30) was compared to a control group of healthy females (N = 45) on measures of opportunities for social interaction, similarity to their best friend, social capability, friendship quality, and psychological adjustment. Results revealed that health condition and friendship precursors were not associated with friendship quality. However, higher friendship quality was predictive of fewer externalizing symptoms for healthy girls. Additionally, positive parent relationships predicted fewer internalizing symptoms for both groups of females. Notably, chronically ill girls noted their friendships were higher in punishment and lower in companionship than healthy girls. Further assessment, including objective measures, will elucidate the beneficial processes of friendships and parent-child relationships that buffer youth from maladjustment.

Effective emotion regulation plays an important role in psychological health. Two commonly-researched emotion regulation strategies are reappraisal, a cognitive change-based strategy, and mindfulness, an acceptance-based strategy. Although their potential in facilitating adaptive emotion regulation has been empirically demonstrated, little work has directly compared their cognitive and emotion regulatory effects, particularly in a symptomatic population. Using an analogue depressed sample, this study examined the relative effects of mindfulness and reappraisal in reducing sad mood and whether individual differences in trait mindfulness and habitual use of reappraisal moderated the effects. The study also compared the extent to which implementation of these strategies incurred cognitive resources and affected attitudes towards negative experiences. One hundred and twenty-nine participants were randomly assigned to receive training in mindfulness, reappraisal, or no training prior to undergoing an autobiographical sad mood induction. Following mood induction, participants rated their sadness on a visual analog scale before completing a Stroop test. Results showed that mindfulness and reappraisal were superior to no training, and equivalent in their effects in lowering sad moods. Compared to the mindfulness group, the reappraisal group reported significantly higher Stroop interference scores, reflecting greater depletion of cognitive resources. Higher trait mindfulness predicted greater reductions in sadness in the reappraisal group, but not in the mindfulness group. Habitual reappraisal did not moderate the effects of either mindfulness or reappraisal. Mindfulness, relative to reappraisal or no training, resulted in significant increases in acceptance of negative experiences and decreases in maladaptive beliefs about rumination. Overall, the study suggests that although mindfulness and reappraisal are equally effective in down-regulating sad mood, they incur different levels of cognitive costs and lead to differential changes in attitudes towards negative experiences.

Higgins' regulatory focus theory (1997) postulates two cognitive/motivational systems for pursuing desired end states: the promotion and prevention systems. The theory predicts that failure in each system is discriminantly associated with dysphoric and anxious affect respectively; and that significant failure in these systems creates vulnerability to depression and anxiety. This study tested these hypotheses among adolescents who took part in the longitudinal Wisconsin Study of Families and Work. We found partial support for the theory's predictions. Specifically, the original adult Selves Questionnaire (SQ), which was administered at age 13, did not demonstrate the expected discriminant associations with dysphoric and anxious affect and symptoms. However, the Selves Questionnaire - Adolescent Version, which was administered at age 15, yielded partial support for the theory. Ideal self-discrepancy was discriminantly associated with depressive affect but ought self-discrepancy was not discriminantly associated with anxious affect. However, feared self-discrepancy was discriminantly associated with anxious affect, which adds to the literature suggesting that feared self-discrepancy might be a better construct to use in measuring prevention failure among adolescents. The association between self-discrepancy and affect was found cross-sectionally but not longitudinally. The study also tested recently formulated predictions of regulatory focus theory which state that significant failure in one regulatory system is likely to negatively impact the other system (Klenk, Strauman, & Higgins, 2011). No support for this prediction was found. Implications of the findings, and aspects of the study that may have reduced our ability to test the hypotheses of interest, are discussed.

How do infants learn word meanings? Research has established the impact of both parent and child behaviors on vocabulary development, however the processes and mechanisms underlying these relationships are still not fully understood. Much existing literature focuses on direct paths to word learning, demonstrating that parent speech and child gesture use are powerful predictors of later vocabulary. However, an additional body of research indicates that these relationships don’t always replicate, particularly when assessed in different populations, contexts, or developmental periods.

The current study examines the relationships between infant gesture, parent speech, and infant vocabulary over the course of the second year (10-22 months of age). Through the use of detailed coding of dyadic mother-child play interactions and a combination of quantitative and qualitative data analytic methods, the process of communicative development was explored. Findings reveal non-linear patterns of growth in both parent speech content and child gesture use. Analyses of contingency in dyadic interactions reveal that children are active contributors to communicative engagement through their use of gestures, shaping the type of input they receive from parents, which in turn influences child vocabulary acquisition. Recommendations for future studies and the use of nuanced methodologies to assess changes in the dynamic system of dyadic communication are discussed.

The Systems Dynamics literature demonstrates that individuals have difficulty understanding and working with systems concepts. To model Systems Dynamics (SD), researchers suggest that clients contract with a modeling team to formulate the problem, elicit the mental models of employees at the client, and use software-based simulation tools. This approach is both time-intensive and costly, limiting its use by organizations. This two-part study piloted the Independent Systems Dynamics Elicitation Method (ISDEM), a new method that may be self-administered by teams to reveal individuals' mental models. The first study, a between-subjects design, compared undergraduate participants' responses on the Systems-Based Inquiry Protocol (S-BI) to the ISDEM. Participants reported more relationships and feedback loops using the ISDEM, and obtained significantly higher Systemic Reasoning Level scores. In Study 2, groups of undergraduate participants were asked to brainstorm and develop a collective model of an issue of university interest, using either their typical brainstorming methods, or the ISDEM. Independent coders rated the ISDEM significantly more informative, clear and useful than the control models. In sum, the ISDEM did a significantly better job eliciting individuals' mental models of systems dynamics than traditional measures, and is a valuable new tool for organizations to use to map systemic phenomenon.

Motivated behaviors are essential for the survival and maintenance of life. The ventral tegmental area (VTA) is a midbrain region that has been implicated in motivational processes, such as seeking reward and avoiding harm. It contains dopamine (DA) neurons that project to limbic brain areas and give rise to the prominent mesolimbic DA pathway. In addition, it contains gamma-aminobutyric acid (GABA) neurons that also project to the limbic system as well as other major brain regions, such as the hindbrain and prefrontal cortex. Despite decades of research, the functions of VTA neurons remain mysterious and controversial. According to an influential hypothesis, VTA DA neurons encode a reward prediction error (RPE), a teaching signal that updates the value of learned associations (Schultz, Dayan, & Montague, 1997). It has also been proposed that VTA GABA neurons represent reward expectancy and provide the subtraction needed (actual reward minus expected reward), to compute a RPE (Eshel et al., 2015). According to another prominent hypothesis, however, VTA neurons encode the amount of effort, vigor, or ‘incentive’ we attribute to motivationally relevant stimuli (Salamone & Correa, 2012; Berridge & Robinson 1998). In most studies that attempt to relate VTA neural activity with reinforcement learning (RL) algorithms, the animals are often head-fixed and behavioral measures are usually limited to limb movements or licking. However, restraining the animal does not mean that they do not attempt to move their head and body. This creates a significant confound in all past research on DA neurons encoding RPE. I will argue that the conflict between the two prominent hypotheses of VTA function arises from both conceptual and empirical limitations, including the lack of precise and continuous behavioral measurements. To address these concerns, I first developed a novel head-fixation device that measures the forces exerted by the head in three orthogonal directions (up/down, left/right, forward/backward), as well as the forces exerted by the body (Chapter 2). The device contains load cells that convert analog voltage signals into continuous measures of force while the mice engage in traditional head-fixed tasks. By recording VTA neurons using in vivo electrophysiology and optogenetics while simultaneously measuring the continuous forces exerted by the mice, I found that VTA DA neurons encode the impulse vector (the magnitude and direction of force exerted over time) rather than RPE (Chapter 3). Moreover, according to the impulse-momentum theorem, I show how dynamic vector representations from head-fixed experiments can be translated into kinematic vector representations during freely moving behavior. According to the impulse-momentum theorem, impulse is equal to a change in momentum. In other words, a change in force is equivalent to a change in velocity assuming a constant mass, linking both dynamic and kinematic vector quantities. Then, by using the same continuous force measurements and manipulating the spatial location of reward during a traditional Pavlovian conditioning task, I falsified several key predictions from the RPE hypothesis (Chapter 4). By delivering the same reward in different locations (e.g., keeping the value and prediction constant), I was able to disambiguate an RPE signal from force exertion. I found that VTA DA neurons more precisely represented the impulse vector and not an RPE. Moreover, using a leaky integrator model, single unit activity of DA neurons could be used to predict the forces exerted across time regardless of reward predictability, as well as across multiple timescales. Then, I demonstrated that optogenetic manipulation of phasic DA activity has no impact on learning but directly modulates performance. At the same time, by using the same manipulations, I falsified the expectancy hypothesis of VTA GABA neurons and demonstrated they also represent vector quantities of force rather than expectancy. I found that VTA GABA neurons show opponent activity (increases or decreases of their firing rate) based on the direction of movement, despite the same level of expectancy and value (Chapter 4). Moreover, I utilized the leaky-integrator model to show that VTA GABA neurons represent the integral of DA activity. Finally, using in vivo electrophysiology, optogenetics, in vivo calcium imaging, and 3D motion capture during freely moving behavior in a novel reward tracking task, I found that a subset of VTA GABA neurons precisely represent three-dimensional rotational kinematics (Chapter 5). Taken together, these results demonstrate that the VTA controls the kinematics and dynamics necessary to control all motivated behaviors such as orientation, approach, and avoidance; whether to seek reward or avoid harm. These data unite the directional and activational components of motivation and provide precise physical quantities to influential concepts such as effort and vigor. Furthermore, I show the computational interaction between VTA DA and GABA neurons and demonstrate how they both participate in controlling the force vectors. Consequently, I made significant steps towards understanding how the VTA controls motivated behaviors and also falsified several key predictions of the RPE hypothesis, as well as improved the effort-related hypotheses. Thus, I have developed a new and comprehensive framework of VTA functioning.

The goal of this dissertation is to characterize goal directed proactive behavioral responses to threat as well as reactive responses to threat exposure, and to identify the neural and personality correlates of individual differences in these responses. Three specific studies are reported wherein participants completed a novel shock avoidance paradigm while concurrent measures of behavioral, muscular, and sympathetic autonomic activity were collected; self-report was used to measure mood and trait personality; and blood oxygen-level dependent functional magnetic resonance imaging (BOLD fMRI) was used to measure individual differences in threat-related amygdala reactivity and intrinsic connectivity within the corticolimbic circuit.

Results from Study 1 demonstrate that during threat exposure, participants exhibit increased avoidance behavior, faster reaction times, and increased muscular and sympathetic activity. Moreover, results demonstrate that two broad patterns characterize individual differences in how participants respond during avoidance: 1) a generalized tendency to exhibit magnified threat responses across domains; and 2) a tendency to respond either with proactive behavioral responses or reactive autonomic responses. Heightened state anxiety during the shock avoidance paradigm, and increased trait anxiety were both associated with the generalized tendency to exhibit magnified threat responses. However, gender moderated the relationship between trait anxiety and generalized increases in threat responses during avoidance, such that only male participants exhibited a positive relationship between these two factors. Study 2 demonstrates that intrinsic connectivity between the dorsomedial prefrontal cortex and centromedial region of the amygdala prospectively predicts whether participants will respond proactively or reactively during active avoidance. Finally, Study 3 provides evidence that responses to threat-related facial expressions within the centromedial region of the amygdala are associated with more reactive and less proactive responses during avoidance.

These results demonstrate that patterns observed in animal models of avoidance, specifically the competition between proactive and reactive responses to threat cues, extend to human participants. Moreover, our results suggest that while anxious mood during performance and heightened trait anxiety are associated with a generalized facilitation of threat responses across domains, measures of neural circuit function within the corticolimbic system predict whether individuals will exhibit increased proactive or reactive responses during active avoidance. In addition to facilitating the search for the neural processes underlying how the brain responds dynamically to threat, these results have the potential to aide researchers in characterizing the symptoms and neural processes underlying anxiety disorders.

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.

Children and adolescents with sickle cell disease (SCD) are at high risk for medical complications, neuropsychological sequelae, and lower overall quality of life. One target of intervention that can positively impact these outcomes is treatment adherence. Despite the known benefits of treatment adherence for health outcomes, children with SCD encounter several barriers that result in low overall levels of adherence and reduction of treatment benefits. Furthermore, little is known regarding the relationship between adherence and quality of life for this pediatric population. As such, two studies were conducted in order to (a) examine the relationship between treatment adherence and quality of life among youth with SCD, and (b) examine the feasibility, acceptability, and preliminary efficacy of a novel mobile health intervention to improve adherence among youth with SCD. For the first study, 46 children and adolescents with SCD and a caregiver were recruited. Results indicated that participants with good adherence had significantly higher parent-reported quality of life than participants with poor adherence. In contrast, based on child self-report, participants did not differ across quality of life domains. Subsequently, 43 participants were recruited to participate in the pilot intervention study, the Intensive Training Program (ITP). The intervention was conducted in two phases: Phase I recruited participants receiving iron chelation therapy to reduce the risk of iron overload associated with chronic red blood transfusions (n=11); Phase II broadened the scope of participants to those prescribed hydroxyurea (HU; n=32), a once daily oral medication. Results indicated that patients and their caregivers endorsed high levels of acceptance, ease of use, and satisfaction with mobile health technology. In addition, participants encountered several technological issues that limited access and resulted in poor compliance with the ITP for some participants early on in the study. Despite this, participants demonstrated significant increases in medication possession ratio (MPR) based on pharmacy refill as well as sustained improvements in disease knowledge. Adherent participants demonstrated significant decreases in outcomes related to caregiver burden as well as significantly lower pain impact when compared to non-adherent youth. In addition, children who were adherent reported quality of life and overall SCD-related functioning at a clinically-significant higher level when compared to those who were non-adherent. Implications for future research and application to clinical care are discussed.

In addition to the adverse effects of high blood pressure (HBP) on cardiovascular disease, HBP is also associated with increased risk of stroke, dementia, and neurocognitive dysfunction. Although aerobic exercise and dietary modifications have been shown to reduce blood pressure, no studies have examined the effects of a combined aerobic exercise and dietary intervention on neurocognition among individuals with HBP, a group at elevated risk for neurocognitive dysfunction. As part of a larger investigation, the ENCORE study, this study examined the effects of dietary modification alone and combined with aerobic exercise on neurocognitive function among individuals with HBP. One hundred twenty five individuals with high normal blood pressure were randomized to an aerobic exercise and dietary modification group (DASH + WM), dietary modification alone (DASH-A), or a usual care control group. Participants completed a battery of neurocognitive tests assessing executive function and vigilance at baseline and again following the four month intervention. Following the intervention, participants in the DASH + WM and DASH-A groups exhibited modest improvements in neurocognitive function relative to controls, and these changes appeared to be mediated by improved cardiovascular fitness and weight loss. A combined aerobic exercise and dietary intervention improves neurocognitive function among individuals with HBP.

Emotions are pervasive in daily life, and a rich literature has documented how emotional stimuli and events disrupt ongoing processing and place heightened demands on control. Yet the executive control mechanisms that subsequently resolve that interference have not been well characterized. Although many failures of executive control have emotion at their core, numerous questions remain in the field regarding interactions between emotion and executive control. How do executive processes act on affective representations? Are emotional representations less amenable to control? Do distinct processes or neural networks govern their control? The present dissertation addresses these questions by investigating the neural systems and cognitive processes that support executive control in the face of interference from affective sources. Whereas previous research has emphasized the bottom-up impact of emotion on cognition, this dissertation will investigate how top-down executive control signals modulate affect's influence on cognition. Combining behavioral techniques with neuroimaging methodologies, this dissertation characterizes the interactive relationship between affective processes and top-down executive control and the ramifications of that interaction for promoting adaptive behavior.

Cognitive and behavioral phenomena related to affective interference resolution are explored in a series of research projects spanning attention and memory. Task-irrelevant affective representations may disrupt performance, but this interference appears to be dependent on top-down factors and can be resolved by executive mechanisms. Interference resolution mechanisms act on representations both of stimuli in the environment and information stored in memory. The findings reported here support emotion's capacity to disrupt executive processing but also highlight the role executive control plays in overcoming that interference in order to promote adaptive behavior.

In the face of declines in memory related to specific events, people maintain intact general knowledge into very old age. Older adults often use this knowledge to support their remembering. Semantic illusions involve situations in which presented information contradicts correct knowledge; the illusion occurs when people fail to notice a contradiction with what they know. Compared to younger adults, older adults' later memories are surprisingly less affected by semantic illusions. That is, they use fewer errors seen in the semantic illusions as answers when later asked related general knowledge questions. Why do older adults show this reduced suggestibility, and what role does their intact knowledge play? In 5 experiments, I explored these questions. Older adults' reduced suggestibility was not due to an age difference in error detection: older adults were no better than younger adults at detecting the errors that contradicted their stored knowledge. In addition, episodic memory failures were not a major factor either; the evidence for their direct involvement was mixed. Instead, prior knowledge seems to have been particularly protective for older adults. They demonstrated more knowledge to begin with but also gained access to even more of their stored knowledge across the duration of experiments, leading them to be less suggestible following semantic illusions. There was also an indication that when knowledge was stably accessible, older adults had a tendency to rely on it more than did younger adults. Broadly, these findings indicate that older adults' intact prior knowledge provides important benefits to their remembering and can even protect them against acquiring erroneous information about the world.

Preliminary evidence demonstrates that age-related differences in episodic memory performance become greater in tasks that have greater perceptual demands (e.g., task stimuli are visually degraded), but are attenuated in tasks that have greater semantic demands (e.g., task requires utilizing previous knowledge). This work suggests that age-related differences in how perceptual and semantic information are represented in the brain have an impact on episodic memory. Broadly, the goal of this thesis was to investigate this idea. To investigate this goal, while undergoing functional magnetic resonance imaging scanning, samples of younger and older adults studied and later retrieved their memories of pictures of either scenes (Study 1 and 2) or objects (Study 3). The first two studies found that, compared to younger adults, in older adults, (1) in occipitotemporal cortex, the quality of perceptual-related representations was attenuated, but, intriguingly, (2) in anterior temporal lobes and prefrontal cortex, the quality of semantic-related representations was similar and even enhanced; these effects were found to be related to episodic memory. Study 1 demonstrated this pattern in individual brain regions and Study 2 demonstrated that this pattern was also present in how information was distributed across the whole-brain network. In Study 3 it was found that these age-related differences in functional neural representations are the result of age-related visual signal loss and compensatory semantic-enhancing mechanisms. Taken together, the three studies highlight that age-related differences in neural representations have an impact on cognition and especially episodic memory.

Advanced age is associated with substantial changes in the brain. These changes can be attributed to many difference sources, such as detrimental effects of aging, brain’s compensatory responses to such negative effects, and cognitive or neural resources acquired over lifespan. As a result, under the same cognitive task, healthy older adults (OAs) often show recruitment of brain regions that are different from healthy young adults (YAs). These observations have been drawn from functional magnetic resonance imaging (fMRI) studies on aging and cognition, which have been largely based on univariate analysis that relates experimental conditions to activity level in individual brain region. While univariate analysis reveals the age differences in the recruitment of brain regions, much remains unknown regarding how these regions are playing their roles. Meanwhile, recent methodological advances in cognitive neuroscience have provided the opportunities to examine 1) functional communications across brain regions, and 2) information stored in the distributed neural representation in a region. In this dissertation, I described age-related differences in these two novel perspectives in a series of fMRI studies on episodic memory, a domain of cognition that is particularly affected by aging. In these studies, healthy YAs and OAs encoded and later retrieved images of scenes or objects inside the scanner. Analyses on functional brain network and neural representations were conducted on the neuroimaging data. These analyses revealed three main findings. First, neural representation and functional connectivity revealed reduced involvements of the core task regions in OAs. During encoding, early visual cortex (EVC) in OAs exhibited reduced representation of visual information. During retrieval, medial temporal lobe (MTL) in OAs exhibited reduced reconfiguration of functional connectivity associated with successful remembering. Second, enhanced recruitments of additional neural resources in OAs were also observed. During encoding, anterior temporal lobe (ATL) in OAs exhibited enhanced semantic representation. During retrieval, prefrontal cortex (PFC) in OAs showed enhanced functional connectivity and stronger reconfiguration of connectivity associated with successful remembering. Finally, we found that schematic knowledge affected functional communication in PFC and semantic representation in ATL differently in the two age groups, suggesting that schema-related strategies may be preferentially selected by OAs. Taken together, these studies depicted the detrimental effect of aging and brain’s adaptive changes in two novel perspectives: functional communication and information processing, which may contribute to a more comprehensive understanding of episodic memory function in aging populations.

Eating disorders pose a serious threat to the physical and mental health of those who suffer from them. Given the impact of these disorders and difficulty treating them, it is important to understand the nature of them and factors involved in their development and maintenance. The empirical investigation of eating disorders is made difficult by the extreme heterogeneity seen within current DSM-IV diagnostic categories. Research on emotion regulation in eating disorders is rising, yet scant in terms of identifying specific difficulties and points of intervention. The proposed study focused on the construct of emotion regulation and its relation to the eating disorders by: (1) empirically identifying groups of eating disorder participants based on symptoms and (2) examining specific difficulties in emotion regulation capacities in each of the identified groups of eating disorder participants and (3) identifying whether difficulties in emotion regulation contribute to eating disorder symptom severity. A clinical sample of individuals with eating disorders was classified into subgroups based on symptom frequency using latent profile analysis. The most parsimonious and best fitting model was a four-profile solution which resulted in four distinct subgroups. Profile 1 consisted of individuals who endorsed moderate restriction and occasional binge eating and vomiting, all at a subclinical level. Profiles 2, 3, and 4 all met criteria for bulimia nervosa and consisted of individuals who engaged in restriction, binge eating, and purging though in varying degrees. When these groups were compared to a sample of college aged healthy control participants using multivariate analysis of variance, results indicate that individuals in profile 1, which comprised 71% of the sample, experience greater difficulty with emotion regulation in the areas of awareness, nonacceptance, and perceived access to strategies to help them feel better. Results of three hierarchical regression analyses showed that difficulties in emotion regulation did not significantly contribute to symptom severity as anticipated..