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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

Perceptions of healthy and unhealthy romantic relationships : a comparison of typically developing adolescents and individuals with a diagnosis of Autism Spectrum Disorder (ASD)

Wilding, Lucy January 2016 (has links)
Individuals with autism spectrum disorder (ASD) may be vulnerable to experiencing unhealthy relationships due to specific individual differences, different opportunities and experiences or, in line with an ecological perspective, a combination of both. The purpose of this research was to explore the perceptions of individuals with ASD, with regards to healthy and unhealthy relationships, and to examine the learning sources considered most valuable to them. Participants included 11 adolescents with ASD and a comparison group of 13 typically developing individuals. Participants completed the Attitudes towards Dating Violence Scales (Price et al., 1999) and were interviewed using an adaptation of the Ideal Self technique (Moran, 2001). Thematic analysis indicated a number of similarities between participants. Individuals with ASD, however, were more likely to discuss the following: direct behaviours within unhealthy relationships; concrete rules to guide expectations; a need for sameness; and the influence of formal learning opportunities. Implications for sex and relationship education are discussed and the role of educational psychologists is highlighted.
322

Acknowledging individual strengths, interests and needs of pupils with Autistic Spectrum Conditions : questioning 'Theory of Mind' (a pilot study)

Tee, Abigail January 2016 (has links)
Research investigating children and young people’s (CYP’s) performance in standard False Belief (FB) tasks, such as ‘The Sally Anne Task’ has highlighted that CYP with autistic spectrum condition (ASC) have difficulties in passing the task and demonstrating Theory of Mind (ToM), in comparison to CYP with ‘neurotypical’ development. This finding has led to the suggestion that individuals with ASC may have deficits in their ToM (Baron-Cohen, Leslie & Frith, 1985). The present research aimed to explore whether there were differences in the performance of pupils with ASC on ‘The Sally-Anne Task’ compared to an adapted task, which was tailored to the individual’s strengths, interests and areas of need (via information from a template about the pupil supplied by helpers). Nineteen pupils with a diagnosis of ‘autistic spectrum disorder’ between the ages of 6 and 10 years (mean = 8.47 years, standard deviation = 1.12 years) were recruited from mainstream classrooms or specialist resource bases attached to mainstream classrooms in three Welsh and five English primary schools. A pragmatic research framework employed a within subjects design; each pupil took part in the two (counterbalanced) tasks. A McNemar’s Exact test revealed a significant difference between the pass rates of pupils in the standard and adapted tasks (p = .008). Pupils in the adapted tasks were almost twice as likely to pass the tasks (M = .89, SD = .31) as those in the standard tasks (M = .47, SD = .51). Implications for understanding ToM in pupils with ASC are discussed and suggestions for developing support, which focuses on the individual’s strengths and interests, are proposed.
323

Exploring function and effective connectivity of the motor cortex and its role in Tourette syndrome

Pépés, Sophia January 2017 (has links)
Tourette syndrome (TS) is a neurodevelopmental disorder characterised by vocal and motor tics. It is associated with cortical–striatal–thalamic–cortical (CSTC) circuit dysfunction and hyper-excitability of cortical motor regions. TS follows a developmental time course, in which tics often become increasingly more controlled during adolescence. Importantly, however, a substantial minority of patients continue to have debilitating tics into adulthood. This indicates that there may be important differences between adult TS patients and children and adolescents with the disorder. The first aim of my thesis was to explore the excitability of the primary motor cortex (PMC) at rest, during motor preparation, motor execution and the inhibition of action. In Chapters 3 and 4 I demonstrate that, in contrast to studies of adult patients, resting motor threshold (RMT) and the variability of motor-evoked potential (MEP) responses are increased in young people with TS, while the gain of motor excitability in reduced. Furthermore, these differences normalise with age over adolescence. I conclude that these effects are likely due to a developmental delay in the maturation of key brain networks in TS, consistent with recent brain imaging studies of structural and functional brain connectivity. Importantly, these findings suggest that the alterations in brain network structure and function associated with TS may be quite different in children and adult patients with the condition. In Chapter 4, I demonstrate that whilst there is evidence of reduced gain during motor execution in young people with TS relative to controls (Chapter 3), the reduction is likely driven by baseline differences and when corrected to baseline patients with TS show an increased ramping of motor excitability during motor execution. In fact, patients’ tic severity was inversely related to the modulation of motor excitability whereby those with the most severe tics were least able to increase excitability. Patients showed largely the same patterns of change in excitability during motor preparation and response inhibition. However, the extent to which patients could modulate excitability during motor preparation was related to phonic tic severity whereby those with the least severe tics had higher excitability change from baseline. In addition, those that were able to suppress motor excitability to a greater extent whilst inhibiting action had the least severe tics, likely engaging inhibitory mechanisms to a greater extent with the consequence of slower response times during the task. I conclude that the ability to modulate motor excitability is both related to pathology and adaptive compensatory mechanisms that may help in tic suppression. The second aim of this thesis was to explore effective connectivity, excitatory and inhibitory physiological mechanisms and the neurochemistry of PMC in young healthy adults. Subsequent experiments in Chapters 5 and 6 used various transcranial magnetic stimulation (TMS) techniques and proton magnetic resonance spectroscopy (1H-MRS) to investigate these issues. Chapter 5 explored interhemispheric facilitation and inhibition (IHI and IHF) in two directions between bilateral PMC. The results provided evidence for an asymmetry of interhemispheric interactions using dual site TMS (ds-TMS) whereby the left-to-right direction is more inhibitory than right-to-left. Furthermore, females appeared to show greater interhemispheric modulation than males and whilst there was robust evidence for IHI (in the left-to-right direction) IHF appeared to not be robust. Finally, Chapter 6 explored how TMS-induced measures of excitation and inhibition related to 1H-MRS measures of neurochemicals γ-aminobutyric acid (GABA), glutamate (Glu) and glutamine (Gln). GABA is the primary inhibitory neurotransmitter in the human brain and is critical for the regulation of neuronal excitability and the orchestration of neuronal networks and is critically important in neurodevelopmental disorders such as TS. GABA was not found to be related to measures of synaptic neurotransmission as assessed by TMS and neither was Gln. In contrast, Glu was found to be related to a hub of TMS measures, in particular, Glu was positively related to both intracortical facilitation (ICF) and long intracortical inhibition (LICI). Chapters 5 and 6 further uncovered relationships between ds-TMS, pp-TMS and 1H-MRS showing that these various measures likely have overlapping mechanisms. The final chapters extend our knowledge about the PMC and the methodologies used to assess its state. Chapter 5 extends our understanding of the communication between right and left PMC and highlights a normal asymmetry in communication. This is important for understanding neurodevelopmental disorders such as TS of which asymmetry in effective connectivity and brain volume have been implicated. Chapter 6 importantly shows that 1H-MRS measured GABA is likely irrelevant for assessing synaptic neurotransmission and thus its interpretations should be limited to non-synaptic levels of GABA. This is particularly important for TS research in which both changes in GABAA receptor activity is present in the PMC and abnormalities in GABA concentration have been shown.
324

Experiences of aggression and violence across dementia and adult acute psychiatric facilities

Power, Kathryn January 2016 (has links)
This thesis explores care staff and nurses’ experiences of aggression and violence whilst working in dementia and adult acute psychiatric facilities. Chapter one presents a systematic literature review of studies based on the perceptions and impact of aggression from patients with dementia, adopting a care staff perspective. The findings highlighted the subjective experiences of aggression, care staff perceptions of its causes and the physical and psychological impact which aggression had on care staff. A key finding was that care staff perceptions of aggression and its impact influenced patient care and the reporting of aggression. The chapter discusses key implications for practice and policy and identifies recommendations for future research. Chapter two consists of an empirical study exploring nurses’ lived experiences of violence from patients whilst working on adult acute psychiatric facilities. Eight nurses were recruited from two hospital sites and completed semi-structured interviews. Analysis of the data revealed the personal perceptions of violence and its causes and the psychological, physical, occupational and relational impact that violence had on the nurses. All nurses employed individual and group survival strategies to help manage their experiences of violence and its impact. Implications for clinical practice and policy and recommendations for future research are discussed. Chapter three presents a reflective account of my research journey throughout training to be a Clinical Psychologist. I use a reflexive stance to explore the development of my research interest, the meaning of violence and to discuss my own responses to the nurses’ experiences. The paper also explores how I managed different roles during the research process and how I have developed as a clinician and researcher.
325

Auditory selective attention in typical development and Auditory Processing Disorder

Stewart, Hannah J. January 2017 (has links)
This thesis examines auditory selective attention as a possible cause of Auditory Processing Disorder (APD). APD is a diagnosis based on the clinical needs of the 5% of children who present with listening difficulties but demonstrate normal hearing. This thesis will focus on developmental APD, which affects children with no known infection, trauma or primary cause inducing their listening difficulties. It will seek to address the current lack of understanding of the root causes of APD, which leads to significant variation in clinical referral routes, resulting in inconsistent methods of diagnosis and treatment. APD has historically been approached via a bottom-up route of assessing auditory processing skills, such as temporal-spatial abilities. The inconsistent results of bottom-up studies has led to debate regarding the diagnosis and treatment of APD, resulting in extensive batteries of tests being conducted on children. However, recent evidence suggests that studies on the causality of APD should be refocused on top-down processes such as auditory attention and memory – hence the focus of this thesis on auditory selective attention. The thesis begins by assessing a new test of auditory selective attention, the Test of Attention in Listening (TAiL), to ensure that it measures auditory rather than supramodal attention. Having established the modality-specificity of TAiL, the thesis examines the development of auditory selective attention to both spatial and non-spatial auditory stimulus features, across tasks of varying levels of perceptual demand. Finally, the thesis assesses the selective attention ability of children with listening difficulties. Specifically, listeners’ selective attention is assessed in both the auditory and visual domains, using both spatially- and non-spatially-based tasks. If auditory selective attention deficits are found in those with listening difficulties, this will provide a basis for the diagnosis and treatment of APD to be constructed and managed from a psychological viewpoint rather than an audiological one.
326

Modulation of neural oscillations and associated behaviour by transcranial Alternating Current Stimulation (tACS)

Vossen, Alexandra Yvonne January 2017 (has links)
Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation method that involves the application of weak electric currents to the scalp. tACS has the potential to be an inexpensive, easily administrable, and well-tolerated multi-purpose tool for cognitive and clinical neuroscience as it could be applied to establish the functional role of rhythmic brain activity, and to treat neural disorders, in particular those where these rhythms have gone awry. However, the mechanisms by which tACS produces both "online" and "offline" effects (that is, those that manifest during stimulation and those that last beyond stimulation offset) are to date still poorly understood. If the potential of tACS is to be harnessed effectively to alter brain activity in a controlled manner, it is fundamental to have a good understanding of how tACS interacts with neuronal dynamics, and of the conditions that promote its effect. This thesis describes three experiments that were conducted to elucidate the mechanisms by which tACS interacts with underlying neural network activity. Experiments 1 and 2 investigated the mechanism by which tACS at alpha frequencies (8 12 Hz, α-tACS) over occipital cortex induces the lasting aftereffects on posterior α power that were previously described in the literature. Two mechanisms have been suggested to underlie alpha power enhancement after α tACS: entrainment of endogenous brain oscillations and/or changes in oscillatory neural networks through spike timing-dependent plasticity (STDP). In Experiment 1, we tested to what extent plasticity can account for tACS-aftereffects when controlling for entrainment characteristics. To this end, we used a novel, intermittent α-tACS protocol and investigated the strength of the aftereffect as a function of phase continuity between successive tACS episodes, as well as the match between stimulation frequency and individual alpha frequency (IAF). Alpha aftereffects were successfully replicated with enhanced α power after intermittent stimulation compared to sham. These aftereffects did not exhibit any of the expected characteristics of prolonged entrainment in that they were independent of tACS phase-continuity and did not show stable phase alignment or synchronisation to the stimulation frequency. These results indicate that prolonged entrainment is insufficient to explain the aftereffects and suggest that the latter emerge through some form of network plasticity. To clarify the nature of these plasticity mechanisms, we then aimed to assess whether STDP could explain the α power increase. We developed a conceptual STDP model that predicted bi-directional changes in α power depending on the relative mismatch between the tACS frequency and IAF. After observing in Experiment 1 that tACS at frequencies slightly lower than the IAF produced α enhancement, Experiment 2 used a similar intermittent protocol that manipulated tACS frequency to be either slightly lower or higher than IAF to respectively enhance or suppress α activity. In addition, a control condition with continuous stimulation aimed to replicate previous results from other groups. However, we did not observe a systematic α power change in any of the active conditions. The lack of consistency between the two experiments raises concerns regarding the reproducibility and effect size of tACS aftereffects. The third experiment investigated the mechanism of online effects and tested predictions that were based on the assumption that entrainment is the underlying process mediating behavioural changes during tACS. We capitalised on two well-described phenomena: firstly, the association between α power lateralisation and visuospatial attention, and secondly, the fluctuation of perceptual performance with α phase. Specifically, the experiment tested whether event-related α-tACS applied over right parieto-occipital cortex can induce a visuospatial bias in a peripheral dot detection task that would reflect α power lateralisation, and whether detection performance depends on the phase of the tACS waveform. In control trials either no tACS or 40 Hz-tACS (gamma) was applied to make use of the putative opposing roles of alpha and gamma oscillations in visual processing. As expected from lateralised enhancement of alpha oscillations, visual detection accuracy was weakly impaired for targets presented in the left visual field, contralateral to tACS. However, this effect was neither frequency specific nor waveform phase-dependent. Therefore, it is unlikely that the negative effect of tACS on visuospatial performance reflects entrainment. Overall, the results of these experiments only partially met our hypotheses. Experiment 1 produced the α enhancement that was expected based on the literature while the follow-up experiment failed to reproduce these results under similar conditions. This outcome demonstrates at best that tACS aftereffects on α activity are not robust, may vary widely across individuals, and might be extremely sensitive to small changes in experimental parameters and state variables. The results of the third experiment call into question the assumption of online entrainment as basis for the observed behavioural effect. These findings point to the need for improved methodology, for more systematic and exhaustive exploration of the relative effects of tACS across different parameter settings, tasks, and individuals; and for the replication of promising but thus far often anecdotal results. They also inspire guidelines for more informative experimental designs.
327

Neurophysiological correlates of ecstasy/MDMA use on executive functioning

Roberts, C. A. January 2014 (has links)
The purpose of this thesis was to assess the integrity of the serotonin system, by measuring the neurophysiological response to tasks that measure executive functions, and neuroendocrine function in ecstasy users and non-users. Each of the proposed executive functions outlined in Miyake et al.’s (2000) conceptual framework (inhibition, switching and updating) as well as the addition of access to semantic/long term memory made by Fisk and Sharp (2004), was assessed using behavioural tasks in combination with EEG and fNIRS. Behavioural performance between ecstasy users and various controls (polydrug and drug naive) was equivalent throughout the thesis. However ERP analysis revealed ecstasy-related atypicalities in cognitive processing during inhibitory control, switching and access. Ecstasy users displayed increases in P2 and N2 components during these tasks that reflect recruitment of additional resources. A diminished P3 response during the switching task was evident for ecstasy users and polydrug users relative to controls. Regression analyses suggest that lifetime cannabis use may be an important factor for this function. Results from fNIRS suggest that ecstasy users show an increased haemodynamic response during all four executive functions relative to non-users, which suggests that ecstasy users are engaged in more effortful cognition than controls. Increases in neuronal activation whilst performing at a similar level behaviourally are understood as recruitment of additional resources. Again during switching cannabis use may have been an important factor. Another aim of this thesis was to assess neuroendocrine function. Ecstasy users displayed elevated basal cortisol levels relative to polydrug controls and drug naive controls. The results suggest that ecstasy is detrimental to the integrity of the HPA-axis. This thesis provides support for ecstasy-related damage to the serotonergic system and should be used in educating prospective ecstasy users of relative harms.
328

Social cognition in epilepsy

Mccagh, Jane Teresa January 2009 (has links)
Some of the psychological problems associated with epilepsy have their origins in the ability of people with epilepsy (PWE) to engage in meaningful and appropriate social interactions. PWE often report difficulties in social settings, yet there is a paucity of research investigating the socio-cognitive skills of this group. This thesis aimed to investigate these skills and relate them to the patient's perceived impact of epilepsy on their social competence. An additional objective was to see whether studying social cognition in focal epilepsy might provide some insight into the organic basis of social cognitive abilities in the normal population. The thesis consists of four separate studies which aimed to investigate social cognition and social functioning in patients with focal epilepsy. With this in mind, a test battery assessing a range of skills linked to social cognition was administered to a cross section of experimental groups (N=95). These included patients with seizure foci in the right frontal lobe (RF), left frontal lobe (LF), right temporal lobe (RT), left temporal lobe (LT) and a group with idiopathic generalised epilepsy (IGE). A normal control group (NC) and a frontal head injured (FHI) group with no epilepsy were also recruited for the study. In Studies 1 and 2 theory of mind (ToM) deficits were apparent in people with RF and LT epilepsy. These groups demonstrated impairment in the appreciation of false belief and deception at first and second order levels of intentionality. They also exhibited deficits in the appreciation of pragmatic language when attempting to infer the meaning underlying hints given by story characters. These impairments were in part attributable to deficits in narrative memory in the LT group. In Study 3 embedding problems within a social context significantly facilitated conditional reasoning in the NC, LT and RF groups but not in the other experimental groups. This finding was unexpected and suggests a double dissociation between ToM and social conditional reasoning. Study 4 investigated the extent to which socio-cognitive impairment was associated with the perceived impact of epilepsy on everyday social functioning. No statistically significant relationship between these variables was found, although a significant negative correlation between education level and impact of epilepsy was observed. Taken together the findings suggest that impairment in ToM may be a particular feature of right frontal lobe pathology and that social conditional reasoning and ToM may be functionally dissociated. PWE do not appear to have insight into their social functioning difficulties, which may well reflect underlying pathology. In light of this, future research should obtain objective measures of social competence from `significant others'. This is the only series of studies to date to assess social cognition in people with frontal lobe epilepsy (FLE) and temporal lobe epilepsy (TLE) within the same design. It is also the first time that social conditional reasoning in epilepsy has been systematically assessed and represents one of the largest lesion studies within the field of social cognition. It is hoped that some of the test material used in the thesis, may prove to be a useful and inexpensive clinical resource to help identify PWE who are at risk of reduced social competence, and in localising the site of seizure foci in patients during clinical audit, particularly where anterior foci are suspected.
329

The development of perceptual-cognitive expertise

Ward, Paul January 2002 (has links)
No description available.
330

The role of the rostral prefrontal cortex in the context of the aesthetic experience

Kreplin, U. January 2014 (has links)
The evaluation of visual art involves sensory, emotional and cognitive processes that lead to an aesthetic judgement or an aesthetic emotion (e.g. beauty). Aesthetic experiences are multisensory processes that undergo a variety of stages. Early processes occur in the visual and sensory cortices, and are central to object identification that may be no different from visual experiences of everyday objects. Later processing stages are related to complex human thought consisting of emotion and cognition that involve areas such as the orbitofrontal cortex, hippocampus and prefrontal cortex (PFC). The later stages are concerned with the comprehension and meaningful analysis of the artwork that contribute to the formation of an aesthetic judgement or emotion. This thesis aims to investigate affective evaluations and their interactions with cognitive processes during the later processing stages of the aesthetic experience in the rostral prefrontal cortex (rPFC). The role of the rPFC will be explored using functional near-infrared spectroscopy (fNIRS) with reference to existing frameworks. Specifically: hemispheric asymmetry in the processing of emotional stimuli, the Gateway Hypothesis and the Default Mode Network will be explored. Experimental WorkA database of sixty images was created in an online survey (chapter 3) at the beginning of the experimental programme. Images were rated online (N = 1028) for complexity, comprehension, novelty, activation, attraction and valence providing stimuli that could be systematically manipulated according to their psychological properties in the experimental studies. The first hypothesis (is the rPFC involved in early perceptual processes such as complexity during aesthetic experience?) was addressed in a pilot study (chapter 4) and repeated in the first experimental study (chapter 5). Both cognitive (high/low complexity) and emotional (positive/negative valence) aspects of the images were manipulated. Images were shown for sixty second and analysed in three time periods (early, middle and late) each consisting of twenty seconds. The results showed an interaction between valence and time with positive images yielding greater activation in the early period and negative images in the late period. This highlighted the importance of long exposure times to capture the aesthetic experience. The second hypothesis (is the rPFC involved in implicit memory formation such as the comprehension of an image during aesthetic experience) was investigated in chapter 6 where the levels of comprehension (high/low) and postive/negative valence associated with the viewed image were manipulated. An interaction between comprehension and valence was found with respect to rPFC activity. Positive easy to comprehend images and negative difficult to comprehend images yielded greater rPFC oxygenation. These findings indicated that the experience of pleasure in positive artworks and increased cognitive effort during the resolution of uncertainty or threat in negative artworks is related to rPFC activation. The third hypothesis (is the rPFC involved in prospective memory during aesthetic experience?) was investigated in chapter 7 where positive and negative artworks were shown under two conditions. Condition one asked participants to introspect about their emotions and condition two to direct their attention to features in the image through a spot-the-difference task. A main effect of emotion was found, but no interaction or effect for condition. Greater rPFC activation was found during the contemplation of positive images. This may be attributed to pleasantness experienced in relation to these images. The last question (is the rPFC involved in self-referential processing and is this important to aesthetic experience?) was investigated in chapter 8 where participants viewed negative and positive images under two viewing conditions. Condition one asked participants to introspect about their own emotions (Self) and condition two about the artist’s emotions at the time of painting (Other). The other-condition resulted in overall greater rPFC activation indicating that participants found it more challenging to think of another’s emotions. An interaction showed greater rPFC activation for positive images in the self -condition and greater activation for negative images in the other-condition. This may have been the result of a positive bias and the detection of self-relevance in positive images and the analysis of threat or uncertainty in negative images. Conclusions: This thesis used a cognitive model of the aesthetic experience as a framework to understand the interaction between emotional and cognitive processes in the formation of an aesthetic judgement or emotion. No evidence for asymmetrical processing of emotional stimuli, or the Gateway Hypothesis was found. The research reported here indicates that the rPFC has an important role during the later processing stages of the aesthetic experience. Viewing negative visual art activated rPFC when the images were difficult to comprehend and when participants thought about the artist’s feelings. Positive emotions, on the other hand, activated rPFC when the images were easy to comprehend and when participants thought about their own feelings. The contemplation of visual art was continuously associated with medial rPFC activation, indicating that the rPFC has a key role in self-relevant processing of visual art. The rPFC may aid personal value judgements of visual art (e.g. this artwork means xyz to me) because this area of the brain mediates the interaction between self-relevance, autobiographical memories and continuously changing emotional states.

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