710 research outputs found
Attachment and Trauma: A Historical and Empirical Study of the Meaning of Unresolved Loss and Abuse in the Adult Attachment Interview
This thesis comprises three studies of the meaning of adults’ unresolved states of mind with respect to attachment (U/d) in the Adult Attachment Interview.
The first study is a historical analysis of the conceptualisation of “trauma” in the unresolved state of mind classification, drawing on published and unpublished texts by Mary Main and colleagues. The paper traces the emergence of the construct of an unresolved state of mind, and places this in the context of wider contemporary discourses of trauma, in particular posttraumatic stress disorder and discourses about child abuse.
In the second study, individual participant data were used from 1,009 parent-child dyads across 13 studies. Interviewees with or without unresolved loss/abuse were differentiated by subsets of commonly occurring indicators of unresolved loss/abuse. Predictive models suggested a psychometric model of unresolved states of mind consisting of a combination of these common indicators, which was weakly predictive of infant disorganised attachment. There was no significant association between unresolved “other trauma” and infant disorganised attachment. The findings provide directions for further articulation and optimisation of the unresolved state of mind construct.
In the third study, first-time pregnant women (N = 235) participated in the Adult Attachment Interview while indicators of autonomic nervous system reactivity were recorded. Unresolved speech about loss was associated with increased heart rate. Participants classified as unresolved showed a decrease in pre-ejection period and blunted skin conductance level throughout the interview. Unresolved states of mind may be associated with physiological dysregulation, but questions remain about the psychological mechanisms involved.
This thesis contributes towards further clarification of the unresolved state of mind construct by examining its historical context, psychometric characteristics, and psychophysiological mechanisms. Further exploratory and theoretical work should focus on improving the definition and validity of the unresolved state of mind construct, to gain a better understanding of how attachment-related experiences of loss and trauma are processed and how this might affect parenting behaviour
When motor control hangs in the balance: Sensorimotor learning during balance-challenging conditions
Maintaining balance while moving is fundamental for safe and successful motor performance. However, this aspect of daily movement is often overlooked in experimental paradigms that assess adaptation during constrained and/or isolated tasks. Consequently, we cannot easily extrapolate the results from these studies to naturalistic motor behaviours. The goal of this thesis is to determine how the necessity to maintain balance during unconstrained movement affects sensorimotor learning. For my first study, I assessed how challenging balance during adaptation affects generalization of learning. Four groups of participants adapted to a new visuomotor mapping induced by prism lenses while performing either a standing-based reaching or walking task, with or without a manipulation that challenged balance. To assess generalization, participants performed a single trial of each of the other group’s tasks without the prisms. I found that both the reaching and walking balance-challenged groups showed greater generalization to their equivalent, non-adapted task compared to the balance-unchallenged groups. I also found that challenging balance modulated generalization across the reaching and walking tasks. For my second study, I tested how challenging balance affected motor memory retention. To do this, the same four groups of participants returned to the lab and repeated their adaptation protocol one week later. I found that only the walking groups demonstrated faster relearning (or savings) during re-exposure to the prisms. Crucially, I found that challenging balance significantly enhanced savings during walking. In my third study, I determined how a stability consequence associated with movement errors affected sensorimotor learning. Two groups of participants adapted to a new visuomotor mapping while performing a precision walking task either with or without the possibility of experiencing a slip perturbation when making errors. I assessed generalization of learning across two visually guided walking tasks and motor memory consolidation. To assess consolidation, I introduced an opposite direction visuomotor mapping following adaptation and evaluated relearning one week later. I found that the experiencing a physical consequence when making errors enhanced generalization and motor memory consolidation. Overall, this thesis provides a novel perspective on how the necessity for balance control contributes to sensorimotor learning, which has intriguing implications for the development of rehabilitation interventions
A randomised control trial for the restoration of functional ability in patients post total knee arthroplasty: a comparison of eccentric versus concentric cycling ergometry
Includes bibliographical referencesPurpose: The predominant impairment to function following a total knee arthroplasty (TKA) is a distinctive reduction in quadriceps muscle strength. It has been suggested that eccentric rehabilitation may be more beneficial than traditional concentric only rehabilitation at improving muscle strength, physical functioning and quality of life in this population. The aim of this study was therefore to determine if an eccentric cycling ergometry rehabilitation intervention (a) was feasible in participant's early after TKA surgery (Study 1), (b) resulted in greater improvements in muscle strength and endurance, as well as muscle activity and muscle volume (Study 2) and, (c)resulted in greater knee functional ability, health related quality of life and physical activity levels (Study 3), when compared to an concentric cycling ergometry rehabilitation intervention. Finally, knee and hip kinematics, ground reaction force and muscle activity was described during the sit-to-stand transfer within this population (Study 4). Methods: Eighteen age- and sex-matched participants', three to nine month's post-TKA were recruited and randomly divided into either an eccentric or concentric cycling rehabilitation intervention. The participants were required to perform three exercise sessions a week, over a period of eight weeks. Isokinetic strength and muscle activity of the quadriceps and hamstring muscles, sit-to-stand motion capture analysis and knee functional ability and health related quality of life questionnaires (Knee Injury and Osteoarthritis Outcome Score, SF-36Health Survey and Tegner Activity Scale) were assessed pre and post- rehabilitation intervention. Data Analysis: Two-way repeated-measures analysis of variance were used to analyse the effects of time and the ECC and CON intervention groups and the group/time interaction for each of the dependent variables. Results: The eccentric rehabilitation intervention was well tolerated with regards to pain levels in participants' as early as three months post-TKA, the peak level of pain perceived per session, never exceeding a "mild" classification. The eccentric intervention resulted in greater power (P= 0.029) and work output (P ≤ 0.001) with a reduced overall heart rate (P= 0.014) ; moderate decreases in biceps femoris (BF) muscle activity (-3.2%) and increases in the lean thigh volume (+807.32) of the uninvolved limb; as well as improvements in the physical fun ctioning (+12.2%) and physical role functioning SF-36 scores (+22.2%) and the level of physical activity (+0.9) (Tegner activity scale). The concentric intervention resulted in decreases in vastus lateralis (VL) muscle activity (-8.17%) and work fatigue (-7.34%) and increases in the lean thigh volume (+677.49) and the hip abduction angle (+ 2.67°) (sit-to-stand) of the involved limb. Conclusion: The eccentric rehabilitation intervention is well tolerated with regards to pain and is characterised by significantly greater power output produced and work performed at significantly lower heart rates. Eccentric cycling ergometry matched in perceived exertion and duration, is associated with greater improvements in physical functioning outcome scores, physical activity level and knee flexion muscle efficiency during concentric contractions, when compared with concentric cycling ergometry. However, knee extensor muscle endurance and efficiency during concentric contractions, as well as muscle volume of the involved limb increased more significantly after concentric training in comparison to eccentric training, Further research is required to establish which training modality is the most feasible and effective in restoring knee function in participant's three months post-TKA
Tales for a teacher’s toolbox: Stories of emergent bilinguals and their funds of knowledge
Through a systematic review of ethnographic studies, this qualitative study collected stories that demonstrate the cultural wealth of emergent bilingual students. The stories collected demonstrate the aspirational, navigational, social, linguistic, familial, and resistant capitals (Yosso, 2005) as well as the experiential and social and emotional assets (WIDA, 2014) of emergent bilingual students. The narratives documented in this study can be retold as counter narratives that contradict commonly held deficit beliefs regarding emergent bilingual students, their families, and their communities
Dynamics of embodied dissociated cortical cultures for the control of hybrid biological robots.
The thesis presents a new paradigm for studying the importance of interactions between an organism and its environment using a combination of biology and technology: embodying cultured cortical neurons via robotics. From this platform, explanations of the emergent neural network properties leading to cognition are sought through detailed electrical observation of neural activity. By growing the networks of neurons and glia over multi-electrode arrays (MEA), which can be used to both stimulate and record the activity of multiple neurons in parallel over months, a long-term real-time 2-way communication with the neural network becomes possible. A better understanding of the processes leading to biological cognition can, in turn, facilitate progress in understanding neural pathologies, designing neural prosthetics, and creating fundamentally different types of artificial cognition.
Here, methods were first developed to reliably induce and detect neural plasticity using MEAs. This knowledge was then applied to construct sensory-motor mappings and training algorithms that produced adaptive goal-directed behavior. To paraphrase the results, most any stimulation could induce neural plasticity, while the inclusion of temporal and/or spatial information about neural activity was needed to identify plasticity. Interestingly, the plasticity of action potential propagation in axons was observed. This is a notion counter to the dominant theories of neural plasticity that focus on synaptic efficacies and is suggestive of a vast and novel computational mechanism for learning and memory in the brain.
Adaptive goal-directed behavior was achieved by using patterned training stimuli, contingent on behavioral performance, to sculpt the network into behaviorally appropriate functional states: network plasticity was not only induced, but could be customized. Clinically, understanding the relationships between electrical stimulation, neural activity, and the functional expression of neural plasticity could assist neuro-rehabilitation and the design of neuroprosthetics. In a broader context, the networks were also embodied with a robotic drawing machine exhibited in galleries throughout the world. This provided a forum to educate the public and critically discuss neuroscience, robotics, neural interfaces, cybernetics, bio-art, and the ethics of biotechnology.Ph.D.Committee Chair: Steve M. Potter; Committee Member: Eric Schumacher; Committee Member: Robert J. Butera; Committee Member: Stephan P. DeWeerth; Committee Member: Thomas D. DeMars
Locally embedded presages of global network bursts
Spontaneous, synchronous bursting of neural population is a widely observed
phenomenon in nervous networks, which is considered important for functions and
dysfunctions of the brain. However, how the global synchrony across a large
number of neurons emerges from an initially non-bursting network state is not
fully understood. In this study, we develop a new state-space reconstruction
method combined with high-resolution recordings of cultured neurons. This
method extracts deterministic signatures of upcoming global bursts in "local"
dynamics of individual neurons during non-bursting periods. We find that local
information within a single-cell time series can compare with or even
outperform the global mean field activity for predicting future global bursts.
Moreover, the inter-cell variability in the burst predictability is found to
reflect the network structure realized in the non-bursting periods. These
findings demonstrate the deterministic mechanisms underlying the locally
concentrated early-warnings of the global state transition in self-organized
networks
Subthreshold Stochastic Vestibular Stimulation Affects Balance-challenged Standing and Walking
Subthreshold stochastic vestibular stimulation (SVS) is thought to enhance vestibular sensitivity and improve balance. However, it is unclear how SVS affects standing and walking when balance is challenged, particularly when the eyes are open. It is also unclear how different methods to determine stimulation intensity influence the effects. We aimed to determine (1) whether SVS affects stability when balance is challenged during eyes-open standing and overground walking tasks, and (2) how the effects differ based on whether optimal stimulation amplitude is derived from sinusoidal or cutaneous threshold techniques. Thirteen healthy adults performed balance-unchallenged and balance-challenged standing and walking tasks with SVS (0–30 Hz zero-mean, white noise electrical stimulus) or sham stimulation. For the balance-challenged condition, participants had inflatable rubber hemispheres attached to the bottom of their shoes to reduce the control provided by moving the center of pressure under their base of support. In different blocks of trials, we set SVS intensity to either 50% of participants’ sinusoidal (motion) threshold or 80% of participants’ cutaneous threshold. SVS reduced medial-lateral trunk velocity root mean square in the balance-challenged (p < 0.05) but not in the balance-unchallenged condition during standing. Regardless of condition, SVS decreased step-width variability and marginally increased gait speed when walking with the eyes open (p < 0.05). SVS intensity had minimal effect on the standing and walking measures. Taken together, our results provide insight into the effectiveness of SVS at improving balance-challenged, eyes-open standing and walking performance in healthy adults
Alles op zijn tijd: over de opvolgende openbaarmaking van inspectierapporten en daarop gebaseerde sanctiebesluiten
The Legitimacy and Effectiveness of Law & Governance in a World of Multilevel Jurisdiction
Bioorthogonal labeling tools to study pathogenic intracellular bacteria
In this thesis, bioorthogonal chemistry is combined with correlative light-electron microscopy to selectively label and study pathogenic intracellular bacteria within the host immune cell. This technique combines the ultrastructural information of transmission electron microscopy with the functional information of fluorescence light microscopy in order to investigate the host-pathogen interactions that contribute to the diseases caused by pathogenic intracellular bacteria such as Salmonella Typhimurium and Mycobacterium tuberculosis. The technique is further expanded with super-resolution microscopy by combining stochastic optical reconstruction microscopy with transmission electron microscopy. Additionally, the bioorthogonal labeling method for the study of intracellular bacteria is validated through a bead-based stability assay, demonstrating the compatibility of alkyne and azide groups to label bacterial proteins within the degradative lysosomal environment. The technique developed in this thesis may contribute to a better understanding of the mechanisms behind bacterial diseases, as well as the development of novel antibiotics and other therapies to fight these important infectious diseases.Bio-organic Synthesi
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