Alumni Dissertations

 

Alumni Dissertations

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  • Motor Control Mechanisms of Whisking in Rat

    Author:
    Wendy Friedman
    Year of Dissertation:
    2010
    Program:
    Psychology
    Advisor:
    H Zeigler
    Abstract:

    Rhythmic movements underlie a large number of critically important motor behaviors. How different levels of neural organization and control interact to produce these movements, then, is a central question in motor control. Using the whisker system in rat we investigate the role played by the motor cortex, a key structure in the generation of complex movements, in the control of whisking. We begin by measuring the movements of the whiskers and the mastacial pad, controlled by the intrinsic and extrinsic muscles, respectively, to clarify the interaction of these two components in the organization of whisking. We find that though both contribute to movement kinematics, the whisker alone makes a relatively larger contribution. We next investigate the relationship between local field potential activity and exploratory whisking and find that brief increases in vMCx activity precede both whisking onset and changes in whisking patterns. Lastly, we investigate the relationship between unit activity in the rhythmic subregion of vMCx and whisking in head-fixed rats engaged in one of two behavioral tasks. We find that spike rate is most often correlated with whisking amplitude/velocity, and that this relationship is independent of behavioral context. We also find occurrences of significant coherence between whisker movements and unit activity, which vary with behavioral task. These results suggest that, though the motor pattern underlying whisking is generated subcortically, vMCx plays a role in both initiating movement and modulating kinematic properties of whisking.

  • THE IMPACT OF MOOD DISORDERS ON COGNITIVE FUNCTION IN POSTMENOPAUSAL WOMEN UNDERGOING TREATMENT FOR EARLY-STAGE BREAST CANCER

    Author:
    Margery Frosch
    Year of Dissertation:
    2010
    Program:
    Psychology
    Advisor:
    Arietta Slade
    Abstract:

    PURPOSE: Many post-menopausal women who are treated for early-stage breast cancer report experiencing cognitive difficulties following adjuvant chemotherapy. However, the generalizability of the results of a number of studies that have attempted to document the association between adjuvant chemotherapy and cognitive dysfunction has been limited due to inconsistencies in the investigative methods used, thus introducing the possibility that other factors are contributing to reports of cognitive problems. The current study examines the possibility that a history of mood disorders in post-menopausal breast cancer patients predisposes them to cognitive difficulties following adjuvant treatment. METHODS: Sixty-five postmenopausal women with non-metastatic breast cancer were administered the SCID-I before adjuvant therapy (Time 1) to determine psychiatric status. Thirty women were found to have a history of mood disorder, while thirty-one women were found to have no history of mood disorder. Participants were administered neuropsychological tests before adjuvant therapy (Time 1), six months after treatment (Time 2), and at a final six-month follow-up (Time 3). Cognitive domains measured included motor, language, attention/concentration/working memory, visuospatial, memory (verbal and visual). RESULTS: Group comparisons found significant differences in several domains at Time 1 (attention) and Time 2 (visual spatial and visual memory), but in each case the mood disorder group means were higher than the group means of the non-mood disorder group. No significant results were found at Time 3. CONCLUSION: In postmenopausal women, a history of mood disorder was associated with higher performance in selected cognitive domains. Reasons for these paradoxical results are explored and suggestions for future research are proposed.

  • Stigma, Intimacy, and Well-Being: A Personality and Social Structures Approach

    Author:
    David Frost
    Year of Dissertation:
    2009
    Program:
    Psychology
    Advisor:
    Suzanne Ouellette
    Abstract:

    There is widespread belief that intimacy and romantic interpersonal relationships are not as meaningful for individuals in or pursuing same-sex relationships as they are for heterosexual individuals. These unfounded stereotypes and assumptions create social stressors in the form of macrosocial and interpersonal stigmatization in lesbian, gay, and bisexual (LGB) individuals' lives. Thus far, social scientists have established general negative associations between experiences of stigmatization and relationship quality among LGB individuals. However, little is known about the processes through which stigma becomes meaningful in the lives of LGB individuals and its resulting impact on their experiences of intimacy and psychological well-being. This dissertation addressed two primary aims: (a) to systematically investigate similarities and differences in LGB and heterosexual individuals' meanings and experiences of intimacy; and (b) to understand the mechanisms that link stigma-related processes to LGB individuals' lived experiences of intimacy and the resulting implications for their relational and psychological well-being. Two mixed-method studies using purposive national online samples addressed these aims. The results of both studies demonstrated that intimacy was experienced as equally meaningful among LGB and heterosexual individuals; however, LGB individuals experienced significantly more adversity in the form of stigma-related processes associated with intimacy compared to heterosexuals. Both studies showed that stigma-related processes were negatively associated with LGBs' experiences of intimacy, relationship quality, and psychological well-being. These associations were partially mediated by the meaningfulness LGBs attributed to their pursuits and experiences of intimacy. Study 2 further demonstrated that individuals in same-sex couples make meaning of their experiences of stigma and intimacy via multiple narrative strategies. Some of these strategies reinforced the negative impact of stigmatization on intimacy, while others allowed individuals to cope with, resist, and overcome stigma-related processes. These findings bolster existing research on stigma and intimacy among LGB individuals. They also challenge researchers to broaden their approaches to address the multiple pathways and mechanisms through which stigma impacts the lives of marginalized individuals. Furthermore, this dissertation demonstrates the utility of a personality and social structures approach to the study of stigma, thereby highlighting important implications for intervention and policy reform.

  • Therapists' Use of their Visual Images in Therapy

    Author:
    DAFNA FUCHS
    Year of Dissertation:
    2012
    Program:
    Psychology
    Advisor:
    Elliot Jurist
    Abstract:

    Therapists frequently experience a spontaneous appearance of a picture or sequence of pictures in their minds, while listening to their patients; in this research project I refer to these experiences as Therapists' Visual Images. The roles that these visual images play in the process of therapy may vary between different therapists, patients, and contexts. The goal of this study is to expand the theoretical understanding of this phenomenon that is common among therapists, but had not yet been studied using a controlled research. This study will examine the scope of the use of visual images that therapists experience during sessions and the processes that lead to these various uses of the image. 15 therapists were interviewed about their experience of having spontaneous visual images in sessions. They were asked about their thoughts and feelings about the experience as well as their use of their images in sessions. The data was coded and distributed to four domains representing the process of the appearance of the image: 1. Before the Image; 2. The Image; 3. After the image; and, 4. Therapists' Theories of the Functions of Visual Images. In further analysis of the results, several processes of visual images were found, resulting in different types of images: Associative Images, Symbolic Images, and Defensive Images. These processes were found to be related to different uses of the image. These finding as well as the limitations of this study are discussed.

  • Getting into character: Cultivating identities in a teen-theatre peer-education program

    Author:
    Valerie Futch
    Year of Dissertation:
    2011
    Program:
    Psychology
    Advisor:
    Michelle Fine
    Abstract:

    This study investigated the role of community theatre participation on adolescent and young adult identity development. The theatre program, known as The SOURCE, focuses on sex-education through a peer-education model. The experiences of young adults, who are now aged 18-34, were examined through interviews (N=20), identity maps (N=9), and a survey (N=64) in order to understand how participation in this group influenced their development. While much of the literature documents the successes of such programs while youth participate, few document the longer-term impacts of such participation (SaldaƱa, McCammon, Omasta, & Hines, 2011). Data reveal how such involvement informed the youths' developing social and interpersonal lives, and their broader understanding of self. The findings show four broad effects that span micro- to macro-level contexts. First, The SOURCE is a unique "safe space" for youth, co-constructed by KT (the director) and the engaged youth, that privileges youth voices and experiences. Second, participation in the theatre program provides an opportunity for developing counternarratives of what it means to be an adolescent, how adolescents and young adults can act as social agents in their communities, and how sex education through peer-education methods can present such opportunities. Third, the findings show that theatre is a particularly valuable medium for engaging in developmental processes because it affords the participants opportunities to "play" with identity while simultaneously expressing emotions and experiences, in addition to learning empathically about the diversity and multiplicity of others. Finally, The SOURCE experience becomes embodied in ways that inform future decisions, identity development, and personal relationships. Narrative analysis of these findings and the mechanisms of such persistence, or "traveling power of self," are discussed. While these findings are encouraging for The SOURCE and from a positive youth development standpoint, they raise important questions about limiting such spaces through broader policies and budget reductions. It is suggested, in the conclusion of this dissertation, that removing the opportunities for participation in such spaces for youth amounts to a "relational injustice," which may have long-term developmental implications.

  • Towards a new model of intervention with Latino families surviving domestic violence

    Author:
    Claudia Garcia-Leeds
    Year of Dissertation:
    2010
    Program:
    Psychology
    Advisor:
    Paul Wachtel
    Abstract:

    Attempts to understand and explain domestic violence have traditionally focused on biological, psychological and sociological models. These multi-modal perspectives have not completely succeeded in providing a truly integrated perspective of Latino families struggling with domestic violence, as they often fail to adequately acknowledge the impact of language, poverty, and undocumented status on the survivors' ability to overcome domestic violence. The goal of this study was to attempt to create a more effective treatment model by leveraging the knowledge and skill sets of those who work most closely with these families in crisis: the direct care workers. The participants, which consisted of the direct care staff of the Latino Domestic Violence Program (LDVP), were interviewed individually, and the data was analyzed in accordance with grounded theory methodology. The participants' responses were not only informative and moving, but also served to bring to the fore a number of important issues that might otherwise have been overlooked. The participants helped identify two main elements that needed to be part of an ideal program. First, the program must be equipped to address all the biopsychosocial needs experienced by the family. These include financial, occupational, educational and mental health needs. Undocumented and non-English speaking clients' needs must be also considered when developing a program for Latino families. Second, it is important that the staff be trained in various theories/models which include an in depth understanding of the clients' culture and where there may be a clash between the values and assumptions of these culture and mainstream America.

  • The Effects of Prompt Fading and Differential Reinforcement on Selection of Novel Activities by Children with Autism

    Author:
    Michelle Garruto
    Year of Dissertation:
    2011
    Program:
    Psychology
    Advisor:
    Nancy Hemmes
    Abstract:

    Individuals with autism often show limited variability in selecting leisure activities. Repeatedly engaging in only one or a few activities may lead to decreased opportunities for social interaction and leisure skill development. The current study evaluated the effects of prompt fading and differential reinforcement on selection of novel activities (activities which had not yet been chosen during a given session), activity engagement, frequency of activity selection, and trials on which each activity was selected, in three students with autism. Prompting consisted of placing a small sticker dot below activities (or on their pictorial representations) that had already been selected during a session. Sticker size was faded systematically. The results show that the use of prompt fading and differential reinforcement for selecting novel activities increased selection of novel activities. Engagement in the activities selected was initially high for each of the three participants, and remained high throughout the study. Although the frequency of selection for each activity became more similar across activities in the post-baseline conditions for all participants, the activity with the highest average frequency of selection in baseline remained the highest throughout the study for two participants. The third participant equalized his selections so that the activity with the highest frequency of selection in baseline had the same average frequency as two other activities in all post-baseline conditions, with those having the highest overall frequency of selection. With respect to the trials on which each activity was selected, the activity chosen on the first trials in baseline continued to be chosen on the first trials throughout the study for one participant. The remaining two participants did show some shift in the activities chosen on the initial trials. This study then, demonstrates the efficacy of a treatment package in increasing the selection of activities not yet chosen in a session. The implications of these findings are discussed with regard to social validity and stimulus control of novel selection behavior.

  • INTER-SUBJECTIVITY AND COLLABORATIVE COMPLEXITY: EFFECTS OF PEER INTERACTION AND CONTEXT IN HEAD START CLASSROOMS

    Author:
    Rebecca Garte
    Year of Dissertation:
    2010
    Program:
    Psychology
    Advisor:
    Anna Stetsenko
    Abstract:

    This study provides an assessment paradigm for examining the quality of children's experiences in preschool. In particular, it focused on peer interactions, as assessed by two measures: peer inter-subjectivity and collaborative complexity. To further understand the relationship between these measures peer interactions were analyzed as nested in activity areas through hierarchical linear modeling. Teacher interactions with the peer group and environmental flexibility of the activity area were also used to explain the relationship between the peer interaction measures. Results showed that the construct of inter-subjectivity was multi-dimensional for this population and sensitive to the immediate social and material context. Higher levels of peer inter-subjectivity were found to predict longer play interactions and greater collaborative complexity. The HLM models also showed that peer interactions varied as a function of activity area, and that environmental flexibility explained some of these differences. In addition, it was found that teacher interactions moderated the relationship between inter-subjectivity and collaborative complexity. In the majority of cases teacher intervention weakened this relationship and had a negative effect on inter-subjectivity levels. In conclusion these results show the theoretical concept of inter-subjectivity to be a valid and useful measurement construct for assessing preschool peer interactions. In addition, the results show that assessments of early childhood education may want to pay more attention to the micro-contexts of the preschool day in order to capture those aspects most salient for children's development. Given that this study was done with a low income sample, it is interesting to note that many of the same findings regarding middle class preschoolers in terms of peer interactions and play were replicated. Future research may want to explore different populations of preschoolers to determine whether the same dimensions of inter-subjectivity are found. In addition, it would be useful to see whether the social skills assessed in this study are linked to concurrent or longitudinal outcomes in related domains of development.

  • The Interaction of Intensity and Deviance on Auditory Event-Related Potentials: Findings Using Principal Component Analysis (PCA) of Current Source Densities (CSDs)

    Author:
    Nathan Gates
    Year of Dissertation:
    2010
    Program:
    Psychology
    Advisor:
    Gerard Bruder
    Abstract:

    Mismatch negativity (MMN) studies provide insights into the brain's ability to perceive and/or detect deviations from established sensory patterns. Clinical studies investigating the loudness-dependency of auditory evoked potential (LDAEP) have shown a relationship between the intensity of an auditory stimulus and neuro-physiological or -chemical activity of the primary auditory cortex. Unfortunately, these two bodies of literature remain disjointed. The present study integrates elements of each body of literature to a) investigate the impact of varying levels of intensity deviance on N1/P2 with a standard set of intensities used in LDAEP paradigms, and b) assess the extent to which deviance-related processes (indexed by MMN) are affected by louder or softer tones. A passive MMN-paradigm used the same stimuli as deviants and standards in order to separate deviance- from stimulus-specific N1/P2 processes. A CSD-PCA approach was used to identify and quantify reference-independent patterns of activity underlying the ERP. Results show that the intensity dependence of N1/P2 is largely dependent on the context in which a given intensity was cast. Namely, a high rate of repetitions of standard intensities produce significant reductions (adaptations) in N1/P2, while N1/P2 enhancement occurred for louder, but not softer deviants. Moreover, MMN amplitude paralleled intensity disparity; however, louder deviants produced greater MMN activity than softer deviants, Intensity Modulation of N1 and MMN presumably reflecting an attentional modulation of sensory processing. A P3a-like vertex source was elicited by the loudest intensity (100 dB), but was absent for all other intensities. Insights gained from this study have direct implications for both clinical LDAEP and MMN studies. LDAEP studies should consider how overlapping or dynamic processes (e.g., adaptation of N1/P2 or elicitation of MMN) influence the amplitudes of N1 and P2. MMN studies should a) consider how attention may interact with intensity to produce distinctly different MMN responses independent of actual deviance-related processes, b) consider how P3a activity reflects a wider range of functions other than `attentional signaling,' such as response inhibition or startle-related processes, and c) consider other physiologically plausible and parsimonious explanations of MMN (e.g., sensory adaptation) when interpreting findings.

  • Sources of dual-task interference in visuomotor tracking assessed with behavioral and fMRI analyses

    Author:
    Yunglin Gazes
    Year of Dissertation:
    2009
    Program:
    Psychology
    Advisor:
    Daniel Kurylo
    Abstract:

    Compensatory tracking was studied alone and simultaneous with a speeded go-no-go task using behavioral and neuroimaging with BOLD fMRI. In the dual-task condition, subjects used their right hand to track while making button presses with their left hand to respond to the secondary task. The study was replicated in two experiments. Replication was tested both behaviorally and with neuroimaging analyses using multivariate linear modeling. Tracking error and joystick velocity were binned into 640 ms and 100 ms intervals centered at secondary task stimulus onset and response in separate analyses to locate the time points at which the tracking behavior showed an interference effect due to the secondary task. Neuroimaging analyses located brain regions associated with compensatory tracking and with dual-task coordination. The binned time-series analyses revealed interference effect in joystick velocity about 200 ms before secondary task response. This finding combined with decreased activation in the left motor cortex during left hand response to a secondary task demonstrated that dual-task interference occurred in the motor preparation stage.