Long Term Effects of Chronic Variable Stress Administered during Different Developmental Stages in Mice

A number of studies have suggested that the occurrence of past trauma can increase an individual\u27s chance of developing PTSD from a new traumatic experience later in life. Trauma that occurs during childhood appears to have a particularly strong effect on this risk increase. Furthermore, conditioned fear responses have been shown to incubate over extended periods of time in animal models. To further investigate the role these phenomena play in the development of PTSD, this study exposed juvenile and adult mice to 7 days of chronic variable stress (CVS). One month later, a Pavlovian delay fear conditioning procedure was used to assess fear learning behavior, and anxiety levels were assessed with an Elevated Plus-Maze (EPM). It was hypothesized that mice who experienced CVS exposure as juveniles would show greater long-term levels of anxiety and long-term sensitization to later fear learning than mice who experienced CVS as adults. Furthermore, mice exposed to CVS, regardless of age, were hypothesized to show significantly enhanced anxiety and fear conditioning relative to control mice. Surprisingly, it was found that stress induced sensitization of fear conditioning deteriorated over the 30-day incubation period for both juvenile and adult mice, leading to no differences between groups, including controls, in fear learning behaviors. Adult stressed mice showed significantly greater anxiety levels than adult controls, while juvenile stressed and control mice showed no difference in anxiety. These results suggest possible neurological differences between juvenile and adult mice in regions involved in fear learning, such as the hippocampus, the central nucleus of the amygdale, and the bed nucleus of the stria terminalis. Alternative interpretations of the data are discussed. Despite failing to support the proposed hypotheses, this study suggests that a successful animal model of PTSD should consider the differential dynamics of associative and non-associative fear learning processes. Furthermore, the moderating effects of developmental stages on the effects of chronic stress should also be acknowledged and investigated further

The Effects of Specific Mental Illness Stigma Beliefs on Treatment Seeking Attitudes

Despite significant gains in the research base and effectiveness of psychotherapy, only thirty to forty percent of individuals experiencing mental illness symptoms seek treatment. A large barrier preventing many individuals from seeking psychotherapy is the stigma that surrounds mental illness. This study reviews the current state of mental illness stigma literature and presents a new Treatment Seeking Barriers Model (TSBM) that attempts to better explain the connection between stigma and treatment seeking. The goal of the current study was to isolate and manipulate responsibility or immutability beliefs related to depression in order to evaluate their relationship with treatment seeking stigma. These beliefs are primary barriers to treatment seeking in the TSBM. Public service announcements (PSAs) trying to increase or decrease beliefs of responsibility or immutability were created. Undergraduate students were randomly assigned to view one of the PSAs, and completed measures of stigma beliefs and attitudes before and after video exposure. Immutability beliefs were effectively decreased, while responsibility beliefs did not change. Furthermore, immutability belief change was significantly predictive of change in treatment seeking attitudes. Immutability beliefs may be a key target for future anti-stigma campaigns, given their sensitivity to brief PSAs observed in this study, as well as their predictive relationship with treatment seeking attitude change

Catastrophe Models for Cognitive Workload and Fatigue

We reconceptualised several problems concerning the measurement of cognitive workload – fixed versus variable limits on channel capacity, work volume versus time pressure, adaptive strategies, resources demanded by tasks when performed simultaneously, and unclear distinctions between workload and fatigue effects – as two cusp catastrophe models: buckling stress resulting from acute workload, and fatigue resulting from extended engagement. Experimental participants completed a task that was intensive on non-verbal episodic memory and had an automatically speeded component. For buckling stress, the epoch of maximum (speeded) performance was the asymmetry parameter; however, anxiety did not contribute to bifurcation as expected. For fatigue, the bifurcation factor was the total work accomplished, and arithmetic, a compensatory ability, was the asymmetry parameter; R2 for the cusp models outperformed the linear comparison models in both cases. A research programme is outlined that revolves around the two models with different types of task and resource configurations

Cusp Catastrophe Models for Cognitive Workload and Fatigue in a Verbally Cued Pictorial Memory Task

Objective: The aim of this study was to evaluate two cusp catastrophe models for cognitive workload and fatigue. They share similar cubic polynomial structures but derive from different underlying processes and contain variables that contribute to flexibility with respect to load and the ability to compensate for fatigue. Background: Cognitive workload and fatigue both have a negative impact on performance and have been difficult to separate. Extended time on task can produce fatigue, but it can also produce a positive effect from learning or automaticity. Method: In this two-part experiment, 129 undergraduates performed tasks involving spelling, arithmetic, memory, and visual search. Results: The fatigue cusp for the central memory task was supported with the quantity of work performed and performance on an episodic memory task acting as the control parameters. There was a strong linear effect, however. The load manipulations for the central task were competition with another participant for rewards, incentive conditions, and time pressure. Results supported the workload cusp in which trait anxiety and the incentive manipulation acted as the control parameters. Conclusion: The cusps are generally better than linear models for analyzing workload and fatigue phenomena; practice effects can override fatigue. Future research should investigate multitasking and task sequencing issues, physical-cognitive task combinations, and a broader range of variables that contribute to flexibility with respect to load or compensate for fatigue. Applications: The new experimental medium and analytic strategy can be generalized to virtually any realworld cognitively demanding tasks. The particular results are generalizable to tasks involving visual search

Long-range Prediction of Epileptic Seizures with Nonlinear Dynamics

Patients with uncontrolled epilepsy have some significant problems with planning life routines, and thus one goal of the present study was to explore the viability of predicting seizures in time intervals of one week. The second goal was to utilize the principle of dynamic diseases and to assess the viability of a cusp catastrophe model for seizure onset that was proposed by Cerf (2006). A seizure history of 124 weeks from one adult male patient fit both the cusp and fold catastrophe models (R2 = .92 and .88 respectively) reasonably well using the pdf method and more accurately than counterpart linear models. Prediction of future states was possible, but somewhat compromised because of the nonstationary nature of the data and uncertainties regarding the control variables in the catastrophe models. Analyses of lag functions, however, revealed some surprising elements, suggesting that the precursory conditions for a seizure could be building up over a period of several weeks and that a self-correcting effect within the nervous system could have been occurring

Education and Training for the Informal Sector

Teaching/Communication/Extension/Profession,