Psychophysical and electrophysiological assessment of early visual processing and emotion recognition deficits in schizophrenia
Year of Dissertation:
2011
Previous data suggest that patients with schizophrenia have preferential magnocellular (M) versus parvocellular (P) visual dysfunction. The goal of Experiment 1 was to characterize M–stream impairment in the patient population using a novel approach. Contrast thresholds at varying luminance levels were investigated. M– and P–biased responses were examined by using scotopic and photopic luminance conditions, respectively. Patients exhibited contrast threshold deficits during scotopic conditions, indicative of M–stream dysfunction. Further, the pattern of contrast threshold responses at photopic levels indicated relatively preserved patient P–pathway functionality.
The effects of estrogen on carrageenan-induced nociceptive behaviors and inflammatory mediators in ovariectomized female mice
Year of Dissertation:
2010
Advisor:
Vanya Quinones-Jenab
Epidemiological studies have shown that pain perception is sexually dimorphic; females tend to experience greater sensitivity to painful stimuli and more chronic pain compared to males. Researchers believe that this dichotomy is caused by the distinct endocrinological profile of females. 17beta -estradiol has been shown to attenuate inflammatory behaviors in both the formalin and carrageenan (Cg) models of inflammation. Research also shows that estrogen affects many inflammatory mediators, including proinflammatory cytokines and prostaglandins (PG). Estrogen plays an important, yet complicated role, in inflammation, and little is known about the specific biochemical mechanisms involved. The objective of this study is to determine if, similar to rats, estrogen attenuates Cg-induced thermal hyperalgesia by altering cytokine or PG release. To that end, female OVX mice were pretreated with various doses of estradiol and injected with 1% Cg. Paw withdrawal latency was recorded prior to, 1 hour, and 5 hours after Cg-treatment in response to a low, medium, and high heat stimuli. Additional animals were treated with indomethacin, a COX blocker. High doses of estradiol caused an increase in nociceptive responses prior to and subsequent to Cg administration. This increase in these pain behaviors was not directly caused by an increase in proinflammatory cytokine levels or a decrease in anti-inflammatory cytokines levels. However, estradiol caused increases in cytokine levels in the untreated paw. Furthermore, treatment with indomethacin caused an attenuation of hyperalgesia. Additionally, indomethacin negated the difference between estradiol- and vehicle-treated mice, indicating that estrogen may interact with prostanoid synthesis. This effect, however, was not seen in the Cg-treated paw, suggesting that estradiol may be increasing hyperalgesia via another pathway as well. Taken together, our results suggest that estrogen's hyperalgesic effects are partly mediated through cytokine up-regulation and prostanoid synthesis, but the main mechanism of action still needs further investigation.
Of home and other figments: The passage of exile in the Tibetan diaspora
Year of Dissertation:
2011
Advisor:
Suzanne Ouellette
This dissertation used a study of lives approach to understand the stories told by four Tibetans who came to New York following the passage of the Immigration Act of 1990 when Tibetans first came to the United States in mass. Not unlike other diasporas in the world today, the transfer of the events, the stories, and in many cases, the wounds, of exile formatively shape the narrative hereafter of younger generations, though this phenomenon has been given little attention in the social sciences. This work asked: 1) What stories of exile are passed from one generation to another and what are the mechanisms of transmission within that passage? (2) How is home understood generationally? (3) And within the experience of exile, what are the possibilities for action in daily life?
Does Discovery-Based Instruction Enhance Learning?
Year of Dissertation:
2010
Since Bruner's (1961) call for research into discovery-based learning, controversy has surrounded the efficacy of such a constructivist approach to instruction (e.g., Tobias & Duffy, 2009). For decades, research has investigated to what extent discovery-based instruction enhances learning tasks or conversely, detracts from them. Research has included wide varieties of domains and discovery-based instructional approaches. Samples have included both children and adults and both novices and experts within their specific domains. It seems that what the field needs is a definition of discovery learning from a practical perspective because a review of the literature reveals that although there might be an implied sense of what discovery learning is, the methodologies employed vary greatly. Furthermore, the characteristics of effective discovery methodology(s) need to be examined with careful consideration of the domain involved, the age of the sample, the comparison condition, and the outcome assessments. Therefore, two meta-analyses were conducted using a sample of 164 studies: the first examined the effects of unassisted discovery learning versus explicit instruction and the second examined the effects of enhanced and/or assisted discovery versus other types of instruction (e.g., explicit, unassisted discovery, etc.). Random effects analyses of 580 comparisons revealed that outcomes were favorable for explicit instruction when compared to unassisted discovery under most conditions, d = -.38 (95% CI = -.44/-.31). In contrast, analyses of 360 comparisons revealed that outcomes were favorable for enhanced discovery when compared to other forms of instruction, d = .30 (95% CI = .23/.36). The findings suggest that unassisted discovery does not benefit learners, whereas feedback, worked examples, scaffolding, and elicited explanations do.
The Temporal Relationship between Daytime Napping and Memory Consolidation
Year of Dissertation:
2011
An extensive body of literature exists substantiating the idea that sleep facilitates the strengthening, stabilization, and protection of newly formed memories, aiding in consolidation from short-term to long-term stores. However, research as to the temporal boundaries of the benefit of sleep to declarative memory is deficient. It has been established that sleep benefits memory compared to equal time spent awake, but when sleep needs to occur relative to the learning period, as well as how much and what type of sleep is necessary, has been little explored. Additionally, researchers have focused on how the brain works on previously encoded information during sleep, but very few have addressed whether sleep prepares the brain to take on new information when it occurs prior to learning. Using efficient daytime naps, the present series of studies addressed these shortcomings and the results provided support exclusively to an active role for sleep in memory processing. Study I unexpectedly demonstrated superior performance for recognition memory with increased delay before sleep onset, resulting in increased slow wave sleep (SWS) in the later nap groups. Study II determined that sleep must progress into SWS, rather than merely Stages 1 and 2, for better short-term retention, subsequent protection from stimulus-related interference, and long-term consolidation, although even a brief nap provides temporary retention benefits over remaining awake. Examining sleep prior to learning in Study III, it was found that a 60-minute nap prepared the brain to more efficiently consolidate information, despite the fact that nap and wake groups encoded material equally. Overall, the present research provides clarification, although perhaps task-dependent, to the existing questions regarding the temporal relationship between sleep and learning. Additionally, the results proffer support for active processing during sleep potentially through standard consolidation and/or homeostatic downscaling of synaptic potentials, the major mechanistic theories ascribing a role for SWS in declarative memory processing.
THE EFFECTS OF ENRICHMENT ON COGNITION IN RATS (RATTUS NORVEGICUS)
Year of Dissertation:
2009
Abstract
FACIAL EMOTIONAL EXPRESSION FOLLOWING VOICE TREATMENTS IN INDIVIDUALS WITH PARKINSON'S DISEASE
Year of Dissertation:
2012
A growing body of work has documented impairments in emotional facial expression (i.e., masked facies) in individuals with Parkinson's disease (PD). These impairments negatively impact patients' social interactions and functioning in daily life. However, little attention has been given to remediating facial emotional expression deficits in PD. Preliminary research has demonstrated that the treatment of voice using the Lee Silverman Voice Treatment (LSVT®; Ramig et al., 1995) has beneficial effects on limited aspects of facial expression in PD (Spielman et al., 2003). The present study extends the literature by examining the effects of two voice treatments on facial expression in PD in a comprehensive way, including facial mobility (FM) and three aspects of facial emotional expressivity (i.e., frequency [EF], variability [EV] and intensity [EI]). Participants included 56 posers, individuals who produced emotional and non-emotional monologues, and 18 raters, individuals who rated posers' facial expressions from video-recorded monologues. Ratings were made on a 7-point Likert scale for the four aspects of facial expression. Raters were trained to criterion, and reliability was high for each emotional expression variable (Intraclass Correlation Coefficient range .85 to .90). The study included four poser groups: 3 PD groups whose posers were randomly assigned into an LSVT, Articulation Voice Treatment (ARTIC), or a no treatment control group, and a demographically matched healthy control group (NC). Findings revealed that PD male posers displayed impaired facial expression at baseline compared to NCs on all variables examined, although PD women did not differ from NCs for any aspect of facial expression. Treatment findings showed that patients who received LSVT were rated as having higher FM, EF, EV, and EI after treatment, four weeks later, than at baseline. This increase was not observed for the 3 other poser groups. It is speculated that LSVT improves facial expression because facial and vocal expression are emotional communication channels that exist within a larger network of emotional processing. Facial and vocal emotional expression are linked at several levels of neural organization: cortical, subcortical, and cranial nerve. The broader clinical implications of our findings are that masked facies can be remediated using LSVT.
Influences of the Female Reproductive Cycle on Inflammatory Induced Pain Resonses
Year of Dissertation:
2009
Advisor:
Vanya Quinones-Jenab
Abstract
Increasing the Variability of Verbal Responding in Children and Adolescents with Autism Using a Conjunctive-Differential Reinforcement Schedule
Year of Dissertation:
2010
A procedure intended to teach variation in appropriate verbal responding to an antecedent stimulus was systematically manipulated for 5 individuals with autism. Four antecedent stimuli that include the clause, "else do you like to do" were presented in a varying order. Five responses that were appropriate to any of the antecedent stimuli were taught using a script-fading procedure. Percentage of varied verbal responses was studied under a conjunctive-differential reinforcement procedure using a multiple-baseline-across-subjects experimental design. Under a modified percentile requirement of the conjunctive schedule, responses were ranked according to their frequency of emission after every session and reinforcement was omitted for the 2 most frequent responses on the subsequent session. Under a lag-1 schedule requirement, reinforcement was omitted for consecutive occurrences of a given response within a given session. Data showed that the percentage of responses meeting the conjunctive schedule requirement increased with the systematic implementation of the schedule. A variability measure showed that responses were more stereotyped during baseline sessions in comparison to treatment
Construction of a Forced-Choice Task for the Assessment of Factual Understanding and Feigning in Competency to Stand Trial Evaluations
Year of Dissertation:
2011
Psychologists are commonly called upon to conduct evaluations of a defendant's competency to stand trial. Under Dusky v. United States (1960) the legal criteria for competency to stand trial were enumerated and since then, a number of standardized assessment instruments that aim to assess those criteria have been developed, each with its own noted strengths and weaknesses. Although there are several instruments available to aid clinicians in these types of evaluations, only three include screens for feigning, and only one assesses for feigned cognitive impairment. In the current research an instrument was constructed to assess for competence related knowledge, while also incorporating several logical and statistical methods to assess for a feigned lack of knowledge of the legal system, including forced-choice testing, floor effect strategies, and completion time methodologies. The Factual Understanding Instrument (FUI) was constructed over five studies. Studies 1-3 involved instrument construction and included a review of the literature, a critical incidents phase with experts in the field, and item construction. Studies 4-5 focused on item evaluation and included an expert review of the constructed items and the pilot testing of the FUI in a simulation study with unimpaired college students. In study 5, multiple statistical analyses were conducted to evaluate the FUI items and the various feigning detection strategies. In this sample reliability of the FUI was high. Items were relatively easy for honest responding participants, with many scoring near perfect. Feigning participants did not score as low as would be predicted by symptom validity testing, as responses varied from less than 50% correct to values seen in honest responders. Intelligence level, item difficulty, and response condition were found to be significant predictors in responses to FUI items. Completion time was not supported as a feigning detection method as hypothesized, however, alternative interpretations of the theory are offered. Further research on the FUI with a known-groups sample in forensic settings is needed to establish a floor value, to further evaluate item performance, and to improve the external validity of the current research. Research methodologies and future directions are offered.