Proteinase-activated receptor 2 (PAR-2) belongs to a novel family of G-protein coupled receptors that are unique in their activation mechanism by which a proteolytic cleavage at N-terminus by a proteinase reveals a ‘tethered ligand’ to activate the receptor. Albeit at a low level, PAR-2 is extensively expressed in normal and pathological brains, including the hippocampus. Qualitative studies into the expression of PAR-2 in several disease conditions, including ischaemia, HIV-associated dementia, Parkinson’s disease, Alzheimer’s disease, as well as multiple sclerosis, have suggested that PAR-2 plays either degenerative or protective role depending on in which cell type an increase in PAR-2 expression is observed. However, its potential roles in modulating neuronal excitability, synaptic transmission as well as network activities remain to be determined. Utilising the whole-cell patch clamp recording technique, I demonstrate, for the first time, that the activation of PAR-2 leads to a depolarisation of cultured hippocampal neurones following application of SLIGRL (100microM), a selective PAR-2 activating peptide (5.52 ± 1.48mV, n=16, P<0.05) and paradoxically a reduction of spontaneous action potential (AP) frequency (29.63 ± 5.03% of control, n=13, P<0.05). Pharmacological manipulation reveals that the PAR-2-mediated depolarisation is most likely dependent on astrocytic glutamate release, which takes effect on ionotropic glutamate receptors. In addition, an overt depression of synaptic transmission among the cultured neurones upon PAR-2 activation is more likely to cause the reduction of spontaneous APs. In further experiments, I show, for the first time, that the activation of PAR-2 induces a long term depression (LTD) of glutamatergic synaptic transmission at the Schaffer collateral-to-CA1 synapse in acute hippocampal slices following SLIGRL (100microM) application (80.75 ± 2.54% of control at 30 minute, n=12, P<0.05). Additionally, this novel form of LTD is independent of metabotropic glutamate receptors but mediated by NR2B subunit-containing N-methyl-D-aspartic acid (NMDA) receptors. It is also suggested from these experiments that glial-neuronal signalling is contributing to this novel form of LTD. In the final set of experiments, by monitoring field potentials in the stratum pyramidale of the CA3 area in acute hippocampal slices, I demonstrate that PAR-2 activation depresses the frequency of epileptiform activities induced by the application of 4-AP/0 Mg2+, an in vitro model of epilepsy (1.53 ± 0.21Hz to 1.18 ± 0.17Hz, n=13, P<0.05, 100microM SLIGRL). In contrast, PAR-2 activation has no effect on the frequency of epileptiform activities induced by bicuculline (0.14 ± 0.03Hz to 0.13 ± 0.03Hz, n=6, P>0.05, 100microM SLIGRL). In summary, in this thesis, I demonstrate that PAR-2 modulates neuronal excitability and depresses excitatory synaptic transmission in the hippocampus. These data indicate that PAR-2 may play a regulatory role in neuronal signalling at single cell level by controlling neuronal intrinsic properties, as well as at synaptic level by tuning excitatory synaptic strength, which ultimately affects global excitability in the neural circuits as a whole. Therefore, this investigation suggests a novel physiological/pathophysiological role for PAR-2 in the brain. These data may reveal valuable clues for the development of drugs targeting a novel and potentially promising candidate.

Typical Rett syndrome (RTT) is a paediatric neurological disorder caused in >95 % of cases by loss-of-function mutations in the X-linked gene, methyl-CpG-binding protein 2 (MECP2). The gene product, MeCP2, is a widely expressed nuclear protein that is especially abundant in postmitotic neurons of the central nervous system (CNS). Knocking out Mecp2 function in mice recapitulates many of the overt neurological features seen in RTT patients and provides a very useful model for testing potential therapeutic applications. The absence of a curative therapy together with the monogenecity of the disorder and established reversibility of the phenotype in mice suggest that replacement of the MECP2 gene is a potential therapeutic option worthy of exploration. In this study I used several viral vectors to test the potential of gene therapy in RTT mice. First, I generated different viral vectors which can express tagged-MeCP2 under the control of ubiquitous and cell-type specific promoters. Secondly, I assessed the ability of these vectors to deliver the Mecp2 transgene into Mecp2 knockout mice at both neonatal and adult stages of development. I then aimed to investigate the effect of exogenously delivered Mecp2 on RTT-like phenotypes. The results demonstrated that lentiviral vectors were able to effectively deliver an RFP-tagged Mecp2 minigene into neurons of Mecp2-null mice both in vitro and in vivo. Exogenous Mecp2 was targeted to the nucleus and displayed heterochromatin localization with no evidence of ectopic expression. Use of the synapsin1 (syn1, neuron-specific) promoter resulted in cellular levels of Mecp2 equal to 85 ± 0.1% of endogenous protein levels, whereas the phosphoglycerate kinase (PGK) promoter produced cellular levels of exogenous Mecp2 at a relatively high levels (210 ± 0.1 % of endogenous levels). Direct brain injection of Lentiviral vector was able to deliver exogenous Mecp2 into the CA1 region of the hippocampus and to produce high transduction efficiency around the injection sites but with limited spread. The early mortality of the injected mice precluded assessment of the functional consequences of exogenous Mecp2 expression. However, assessment of the cellular morphology was possible and this analysis revealed delivery of exogenous Mecp2 to normalise neuronal nuclear volume deficits seen in the Mecp2stop/y mice from 86 ± 0.1 % of WT values to 100 ± 0.04 % of WT levels. At the molecular level, I showed that exogenous Mecp2 3 becomes phosphorylated at serine 421 under basal conditions and that the level of phosphorylation of exogenous Mecp2 is disproportionately higher (5.5 ± 0.4 times) than that seen for endogenous Mecp2. I also showed the Mecp2 overexpression in WT neurons is associated with a reduction in the cellular levels of total histone 4 (78 ± 0.01 % of the endogenous level) and a parallel reduction in cellular levels of acetylated histone 4 (79 ± 0.01 % of the endogenous levels). In second phase of experiments, I showed that the single stranded Adeno-associated virus (ssAAV)-based vector with chicken beta actin (CBA) promoter and encapsulated with capsid of AAV serotype 9, was able to efficiently deliver exogenous MECP2 into the brain of Mecp2-null as well as WT neonatal mice after intracranial (IC) injection. In contrast to lentiviral vectors, there was widespread transduction of cells throughout the nervous system with transduction efficiency varying between 6.8 ± 2.3 % and 41.5 ± 11.3% of all cells dependent on the brain region. The transgene was mostly expressed in neurons which represented 67 ± 11.8 % to 98 ± 0.8 % of all transduced cells. ssAAV9 vector expressed exogenous MeCP2 at near-physiological levels (100-125 % of endogenous levels). At the cellular level, exogenous MeCP2 was able to rescue the neuronal nuclear volume of Mecp2-null mice (69 ± 0.02 % of WT values) to WT comparable values (97 ± 0.03 % of WT values). At the organismal levels Mecp2-null mice treated with ssAAV9/MECP2 showed extended survival (median survival of 16.7 weeks compared to 9.3 weeks for the GFP-treated control) and also displayed a modest, but significant, reduction in the RTT-like phenotype severity score compared to the GFP-treated control group. The most robust improvement reported in this study was in the locomotion activity (velocity and total distance moved in the open field test and in performance on a forced motor task). Interestingly, WT mice receiving neonatal injections of ssAAV9/CBA-MECP2 did not show any significant deficits, suggesting a tolerance for modest MeCP2 overexpression. In a further experiment, I showed that the self-complementary AAV 9 (scAAV9) vector with an Mecp2-endogenous core promoter fragment was able to deliver exogenous MECP2 into the brain of neonatal mice after intravenous (IV) or (IC) injection. Brain transduction efficiency was 8 - 12 % after IV injection and 48 - 68 % after IC injection in neonatal mice. Cellular levels of exogenous MeCP2 were between 1.4-1.8 times the endogenous levels. At the organismal level, 4 scAAV9/MECP2-injected mice displayed an overt hindlimb motor dysfunction which was observed 3 and 5 weeks post-injection after IV and IC injection respectively. The stereotyped hindlimb dysfunction suggested a toxicity issues with this vector and examination of the lumbar segment of the spinal cord confirmed evidence of axonal degeneration in the dorsal columns. IV injection of scAAV9/MECP2 into RAG-/- knockout mice (immunocompromised) displayed hindlimb motor dysfunction similar to that observed with Mecp2stop/y mice suggesting that the adaptive immune response is not likely to be involved in the pathogenesis of this phenotype. MECP2stop/y mice treated with scAAV9/MECP2 displayed higher RTT-like phenotype severity score than GFP-treated controls which is probably due to the effect produced by the hindlimb motor dysfunction on regular RTT-like phenotype (gait, mobility and hindlimb clasping). In summary, I have demonstrated the successful application of lentiviral and AAV2/9 vectors to deliver exogenous MECP2 both in vitro and in vivo. I showed that lentiviral vectors are unlikely to be useful for global brain delivery of MECP2 due to limited spread of the virus. However the lentiviral vectors I developed are potentially useful where localized brain injection is desirable. The main translational finding is the first, at the proof of concept level, demonstration of therapeutic benefits (including enhanced survival) of exogenously delivered MECP2 using the ssAAV9/CBA-MECP2 vector. I also however, identify potential toxicity issues of exogenous MECP2 delivery whereby a scAAV9 vector was found to produce overt neuromotor deficits. Overall, my data supports the potential of gene therapy in RTT but also emphasises the importance of issues including careful vector design, choice of delivery methods and the timing of treatment in any future clinical translation.

1. The hypothalamic arcuate nucleus (Arc) is a key integrative centre of the central nervous system (CNS) involved in the control and maintenance of energy balance. Whole-cell patch clamp recording techniques were utilised, in isolated hypothalamic brain slice preparations, to investigate the electrophysiological and morphological properties of Arc neurones. Differential expression of subthreshold active conductances were identified and used to functionally classify Arc neurones into 8 electrophysiological clusters. This classification was based based upon differential expression of the following conductances: anomalous inward rectification (Ian); hyperpolarisation-activated non-selective cation conductance (Ih); transient outward rectification (Ia); T-type-like calcium conductance. Morphological analysis of recorded neurones, revealed retrospectively with biocytin staining, showed four populations based upon the orientation and number of primary dendrites. There were no obvious direct correlations between morphology and electrophysiological properties, suggesting considerable functional diversity of neurones and their associated circuits at the level of the Arc. 2. The physiological levels of glucose to which the brain is exposed are believed to be around 1-2.5 mM, and glucose-sensing neurones have been identified in the Arc. However, in vitro slice studies routinely use glucose around 10 mM in aCSF. The impact of this high level of glucose on fundamental properties and operation of hypothalamic circuits remains unclear. Here the effect of different ambient glucose levels (10 mM, hyperglycaemic and 2 mM, euglycaemic) on electrophysiological properties of Arc neurones was compared. Significant differences in passive and active subthreshold membrane properties of Arc neurones were observed, including: changes in neuronal input resistance, spontaneous activity and magnitude of Ih and Ia. Data from this study suggests a need to re-evaluate studies previously conducted in non-physiological levels of glucose. 3. The effects of noradrenaline (NA) on the neuronal excitability of hypothalamic Arc neurones were studied. Application of NA induced a membrane depolarisation and increase in electrical excitability in 51% of Arc neurones, including orexigenic NPY/AgRP neurones, a response that persisted in the presence of TTX indicating a direct effect. NA-induced depolarisation was mediated through α1-ARs, in particular through α1A-ARs, and associated with multiple ionic mechanisms including: closure of a potassium conductance, activation of a non-selective cation conductance, or a combination of the two. 4. NA also induced a membrane hyperpolarisation in a sub-population of Arc neurones (15%) including 4/9 putative anorexigenic CART-expressing neurones, the remaining CART neurones responded with a NA-induced excitation. NA-induced hyperpolarisation, mediated via α2-ARs and activation of one or more potassium conductances, persisted in the presence of TTX indicating a direct effect on Arc neurones. 7.5% of neurones responded to NA with biphasic inhibitory/excitatory responses. Taken together, these data suggest that NA, at least in part, excites a subpopulation of NPY/AgRP neurones and inhibits a population of CART expressing neurones which may serve an orexigenic role at the level of the Arc. 5. Histamine induced membrane depolarisation in a population of Arc neurones (65%), most likely through H1 receptors, via a direct effect on the postsysnaptic membrane. Histamine induced depolarisation through multiple ionic mechanisms, including closure of a potassium conductance or activation of an electrogenic pump.

1. The effects of glucose on the electrophysiological properties of rat hypothalamic arcuate nucleus (ARC) neurones were investigated. Neurones were recorded in 10 mM (hyperglycaemic) and 2 mM (euglycaemic) glucose-containing aCSF. The major findings were that input resistance increased in 10 mM glucose, there was an increase in the activity of neurones in 2 mM glucose and there were a greater percentage of neurones expressing lh in 10 mM glucose. Subthreshold active conductances were differentially expressed in ARC neurones including: anomalous inward rectification Q. ), time- and voltage-dependent inward rectification 00, A-like transient outward rectification (IA) and T-type calcium-like conductance. Characterisation of the differential expression of these conductances may represent one way of functionally classifying ARC neurones. 2. Whole-cell patch clamp recording techniques were used in isolated hypothalamic brain slice preparations to investigate the effects of 5-HT on ARC neurones. Bath application of 5-HT induced a membrane depolarisation in a sub-population of ARC neurones (30%), a response that persisted in the presence of TTX indicating a direct effect. 5-HT excited ARC neurones through three potential mechanisms: closure of one or more resting potassium conductances; activation of a non-selective cation channel, or a combination of the two; or activation of a pump in the membrane. This response was mediated through the 5-HT2A. 5-HT2B and/or 5-HT2C receptors revealed using a range of 5-HT receptor agonists and antagonists. 5-HT was shown to excite CART-expressing neurones suggesting an anorexigenic role for 5-HT, via 5-HT2 receptors at the level of the ARC. 3.5-HT induced a membrane hyperpolarisation in a sub-population of ARC neurones (37%). The 5-HT-induced hyperpolarisation persisted in the presence of TTX indicating a direct effect on ARC neurones. 5-HT inhibited ARC neurones most likely through the activation of one or more potassium conductances,including an inwardly rectifying potassium conductance. Potential roles for 5-HTIA, 5-HTIB and 5-HT7 receptors were suggested from studies utilising 5-HT receptor agonists and antagonists. 5-HT inhibited orexigenic NPY/AgRP neurones, identified by their response to ghrelin and by their electrophysiological properties, suggesting an anorexigenic role for 5-HT, acting via 5-HTI and 5-HT7 receptors on NPY/AgRP neurones at the level of the ARC. 4. The effects of feeding-related signals on hypothalamic neuropeptide expression were investigated using real-time-PCR. A new protocol measuring gene expression from hypothalamic explants was developed. Effects of GABA and AMPA on c-fos expression were investigated and subsequent studies showed leptin and glucose modulated the expression of NPY, POMC and AgRP, in fed and fasted animals. Further work is required to validate this novel approach to studying the central control of energy balance.

Major topics of great interest in neuroscience involve understanding the brain function in stimuli coding, perceptive discrimination, and movement control through neuronal activities. Many researchers are designing biophysical and psychological experiments to study the activities of neurons in the presence of various stimuli. People have also been trying to link the neural responses to human perceptual and behavioral level. In addition, mathematical models and neural networks have been developed to investigate how neurons respond and communicate with each other. In this thesis, my aim is to understand how the central nervous system performs discrimination tasks and achieves precise control of movement, using noisy neural signals. I have studied, both through experimental and modelling approaches, how neurons respond to external stimuli. I worked in three aspects in details. The first is the neuronal coding mechanism of input stimuli with different temporal frequencies. Intracellular recordings of single neurons were performed with patch-clamp techniques to study the neural activities in rats somatosensory cortices in vitro, and the simplest possible neural model—integrate-and-fire model—was used to simulate the observations. The results obtained from the simulation were very consistent with that in the experiments. Another focus of this work is the link between the psychophysical response and its simultaneous neural discharges. I derived that under a widely accepted psychophysical law (Weber’s law), the neural activities were less variable than a Poisson process (which is often used to describe the neuron spiking process). My work shows how psychophysical behaviour reflects intrinsic neural activities quantitatively. Finally, the focus is on the control of movements by neural signals. A generalized approach to solve optimal movement control problems is proposed in my work, where pulses are used as neural signals to achieve a precise control. The simulation results clearly illustrate the advantage of this generalized control. In this thesis, I have raised novel, insightful yet simple approaches to study and explain the underlying mechanism behind the complexity of neural system, from three examples on sensory discrimination and neural movement control.

This thesis examines weight anxiety and eating disorders amongst women from an attributional perspective. The studies comprise two distinct but interrelated components: investigations of the role of attribution in the development and maintenance of weight anxiety and eating disorders; and analyses of two screening instruments for eating disorders. The study presented in Chapter 2 examines whether, amongst women without an eating disorder, attributions can be extracted in a factor-analytic manner to form relevant stereotypes associated with 'fat' or 'thin' women. The results confirm that clear weight-related factors can be extracted, and these resemble common stereotypes of fatness and thinness. In Chapters 3 and 4 the attributions of both eating disordered and non-eating disordered women were examined. Four groups have been examined: the Anorexic group; the Bulimic group; the Over-Eater group; and the Non-Eating Disordered group. It is proposed that the attributions of eating disordered women and non-eating disordered women will differ; that the various eating disordered groups will also differ in their attributions; and that attributions will differentially contribute to the development and maintenance of different weight anxieties and eating disorders. The results confirm these propositions: this thesis shows that there are attributionaI differences between the women with and without eating disorders; that there are differences in the attributions of the Bulimic, Anorexic and Over-Eater groups; and that there is evidence to suggest that attributions contribute differentially to the development and maintenance of weight anxiety and eating disorders. The internal validity of the subscale structure of the Eating Disorder Inventory (EDI) (Garner, Olmsted and Polivy, 1983) is examined in Chapters 5 and 6, and Chapter 6 analyses the structure of another assessment instrument, the SCANS (Slade and Dewey, 1986). The results confirm the doubts raised about the validity of the subscale structure of the EDI: no clear support for the subscale structure put forward by Garner et al. has been found, and the factor analyses indicate that no single factor structure can be replicated. The factor analysis of the SCANS, presented in Chapter 6, suggests that the subscale structure of this measure is also not well replicated. It is argued that the subscales of both instruments should be used only with caution. Chapter 5 also examines weight anxiety in older women. This study has shown that older women also are anxious about their weight and that their weight anxiety takes a similar form to those of younger women; for this group of women lifestyle might be an influential factor in their weight anxiety. Chapter 7 discusses all the issues raised in the earlier chapters in relationship to the literature. Finally, the findings of this thesis are discussed, models of the role of attributions are outlined and directions for future research are discussed.

1.6 million young people are currently in higher education (HEFCE, 2010). Even though participation ‘stands at 57% for the 20% most advantaged ... compared to 19% for the most disadvantaged 20%’( Inside Government, 2011), this is an increasingly diverse population. Among the attendant pressures for both students and staff, mental health concerns predominate: since the Royal College of Psychiatrists published their first report into the mental health of students, (RCP, 2003), the issues ‘highlighted have shown no signs of abating and in many respects have become more pressing’ (RCP. 2011:17). Universities for their part increasingly seek to address students’ mental health needs, thereby supporting successful completion of their studies. This doctoral research examines the experiences of ‘home’ undergraduate students in one Russell Group university (henceforth anonymised as Midlands University) and the staff who support them. A qualitative approach serves to highlight the voices of participants and offer an in-depth account of their lived experience of access to, and participation in, the social and academic life of the University. Social Capital theory, Emotional Geographies and the Capability Approach provide a theoretical framework for the analysis of interview data. Key findings confirm the ongoing impact of stigma and discrimination, and indicate the importance of the affective domain of education and the role of student culture on support experiences. The overall aim of this study was to improve student and staff experiences of support. The findings have been and continue to be used to inform policy and practice within the study University.

The ability to restrain oneself from acting on aggressive impulses is arguably a crucial aspect of human functioning and interaction. Yet growing evidence in the literature suggests that people’s self-control resources may be limited and, at times, self-controlled regulation could even increase the association between aggressive triggers and aggressive behaviour. As an alternative, mindfulness practices encourage individuals to be aware and accept their aggression-related thoughts and emotions simply as an ephemeral state rather than to control them. Across four studies, we investigated the possibility that brief, as opposed to extensive, mindfulness exercise may reduce aggression, and whether this potential effect can be separated from a general mechanism of self-control. The relationships between mindfulness, self-control, and aggression were explored in their dispositional forms (Study 1; N = 241). Then, the effect of brief laboratory inductions of mindfulness was tested following manipulations designed to either bolster (Study 2; N = 99) or weaken (cross-cultural samples: Study 3; N = 119 vs. Study 4; N = 110) the resources of self-control. In addition, the potential roles of individual differences in sensitivity to provocations (SP) and frustrations (SF), and self-harm on aggression were also assessed. Results indicated that (i) despite one’s dispositional ability to exert self-control, the presence of a mindful quality uniquely reduced the experiences of anger and hostility, (ii) under the condition of full self-control resource (i.e., after self-control training), mindfulness induction contributed only in reducing more subtle/implicit forms of aggression, and (iii) under lack of self-control resource (i.e., following ego-depleting task), mindfulness induction significantly reduced direct physical aggression after the experience of provocation across cultures. The benefit of mindfulness on aggression appears to be more salient when individual’s self-control resource has been taxed, which operates similarly in Western and non-Western settings. Therapeutic tools focusing on the mechanism for controlling the expression of aggression would benefit from an inclusion of mindfulness-based strategies, as well as an early identification of individual’s sensitivity to different types of aggressive triggers and risks for self-harm.

‘FRIENDS for Life’ is a manualised, 10 week, Cognitive Behavioural Therapy (CBT) based programme designed to be run in school and community settings (Barrett, 2010b). The programme has been introduced to schools within the local authority where the researcher is based via the local Targeted Mental Health in Schools (TAMHS) project. The programme is well reviewed and is recommended by the World Health Organisation for the treatment of anxiety disorders in children (World Health Organisation, 2004). Previous research has evaluated the programme when delivered in closely monitored situations with optimal implementation. The aim of this study is to evaluate the impact of FRIENDS for Life as implemented in a mainstream secondary school by school staff trained as part of the TAMHS initiative. This study makes an original contribution to the existing research base by evaluating the programme in a naturalistic, real world setting using an alternative methodology to the majority of published evaluations. Data regarding implementation of the programme was collected and analysed using activity theory. A single case experimental design was used to monitor the impact of the intervention on the emotional distress, anxiety levels and coping strategies of 5 secondary school participants (aged 11-13) who had been identified by school staff as appearing anxious. The findings suggest that participation in FRIENDS did not result in the hypothesised reductions in emotional distress, anxiety and negative coping skills or the hypothesised improvement in active coping skills. These results are discussed with regard to the finding that some aspects of the programme were not delivered. Analysis of the context using activity theory suggested that factors such as lack of time, space for delivery and experience and training impacted upon implementation. Methodological issues contributing to these findings are considered and implications for the local TAMHS project and for Educational Psychologists are discussed.

The thesis begins with a review of the trauma literature as it relates to fire and rescue work and the attention given to the negative psychological consequences of involvement in such work. Clinical authorities warn of the psychological harm caused by exposure to traumatic incidents despite the recognition that psychological growth often follows adversity. To address this, firefighters were used in a series of studies to investigate the role of social support in facilitating growth. A philosophical overview of current understandings of trauma and growth was made along with the methodology chosen to pursue this investigation. The first empirical chapter is a test of the relation of growth to two different philosophical types of well-being. It found growth to be related to eudaimonic change, rather than hedonic change. A comprehensive review of the literature on social support and growth then found mixed findings for the association of social support and growth but no strong evidence of a causal relation. Four empirical chapters follow that examine the relations between different types of social support and growth in firefighters. The final empirical chapter is a longitudinal study of social support and growth in firefighters based on the findings of earlier cross-sectional studies. Overall, findings were mixed and the role that social support plays in the facilitation of growth remains unclear. A critical realist perspective was taken at the end of the thesis that raises philosophical concerns about clinical understandings of trauma, its treatment and reliance upon a medical framework for explaining psychological change. The findings offer directions in which future research may progress to establish the role of social support in the facilitation of growth following adversity.