Morphological Correlates Of Synaptic Plasticity After Long Term Potentiation In The Rat Hippocampus

Changes in synapse and neuronal morphology have been reported in the rat hippocampal formation after the induction of long-term potentiation (LTP) of the perforant path, although few studies have investigated such parameters in the maintenance phase of L-LTP. Moreover, the results of investigations of synaptic and neuronal morphometry changes after LTP have varied and this could be due to the methods of analysis employed, the choice of stimulation protocol and or whether an in vitro or in vivo study. This in vivo investigation applied unbiased stereological methods to examine the morphology and morphometry of perforant path-granule cell synapses, in the dentate gyrus, after the induction of LTP. Two controls were employed, the contralateral hemisphere of each animal and the inner molecular layer, where the medial perforant path has little synaptic input. Many previous studies of the first 6Omin post tetanisation have used high frequency stimulation (HFS) to induce LTP however, in this study – to determine whether changes in morphology were due to LTP per se - potentiation was induced by theta burst stimulation (TBS). 45min after the induction of LTP there were no significant differences, between hemispheres, in the mean numerical density (Nv) of axodendritic or axospinous asymmetric synapses, or the mean number of synapses per neuron in the middle molecular layer (MML) of the dentate gyrus. There were no significant differences, between potentiated and non-potentiated tissue, in the Nvs of those asymmetric synapses with perforated or concave profiles. Neither were significant differences following LTP demonstrated in the size of the postsynaptic densities of these synaptic subtypes or the volume density of apposition zone (AZ) area (Sv) of individual, or all, asymmetric axospinous synapses. However, there was a trend towards larger perforated synapses in the potentiated hemisphere and, in both hemispheres, concave and perforated synapses were larger than average. In the inner molecular layer (IML), there were no differences except for a significant decrease in the total AZ volume density in the potentiated hemisphere. This would suggest that any morphological modifications taking place in the induction phase of L-LTP may be restricted to a fraction of synapses in the MML, although perforated synapses appear to be involved. The second part of this study examined morphological correlates 24h after the induction of LTP with TBS and HFS. In the MML after induction of LTP with TBS there were significant increases in the Nv of asymmetric axodendritic synapses and the mean number of axodendritic synapses per neuron. There was an increase in the Nv of axospinous synapses and in the mean number of axospinous synapses per neuron that was not significant. This was reflected in significant increases in the total AZ Sv and in the frequency of macular synapses in the potentiated hemisphere. 24h post tetanisation with HFS, there was a significant difference in the Nv of axospinous synapses in the MML of the potentiated compared to the contralateral hemisphere. There were also significant differences in the frequency of synapses with perforated and concave profiles. There were no significant differences in synaptic morphometric parameters, between hemispheres, in the IML after either of the stimulating regimes. Results from the three animals in each group showing the greatest degree of potentiation, were pooled and demonstrated significant differences in the Nv and mean number of axospinous synapses per neuron. There was also a significant difference in the number of synapses with concave profiles but this was replicated in the IML. The effects of these morphological changes, after LTP induction, on the cellular mechanisms involved and on synaptic efficacy are discussed, and possible reasons for the variable pattern of morphology after different stimulating protocols is considered

When Wives Migrate and Leave Husbands Behind: A Jamaican Marriage Pattern

For over a hundred years Jamaicans have been migrating to make the proverbial `better life\u27 for themselves and their families. In the early 20th century husbands migrated, leaving wives behind. As economies of the United States and Canada have become more service-oriented, wives migrate leaving husbands behind. The experiences of Jamaican immigrant women are documented in Caribbean migration studies, but the marriages of Jamaican legally-married immigrant wives and their husbands left behind in Jamaica are so far unstudied. The main research question of this study is what maintains these transnational marriages over time, sometimes for decades, when spouses see each other sometimes only once or twice a year. Data for the study come from: in-depth interviews conducted between 2005 and 2007; conversations held over the past fifteen years with participants in these marriages in the United States and in Jamaica; and participant observation of U.S. and Jamaican societies. The findings reveal that daily companionship in marriage is not as essential a Jamaican cultural value as migration, but that the institution of marriage, although not the dominant form of coupling in Jamaica, is important enough to last. Moreover, divorce still bears a stigma in Jamaican culture. Outcomes of these marriages vary but may not be unpredictable, depending on their pre-migration state and the nature of the living-apart experience. By focusing on these Jamaican transnational marriages, this study hopes to cast another light on Jamaican migration, as well as to encourage further discussion and research of legal marriage in Jamaica and in the Afro-Caribbean

Inclusive, adaptive design for students with severe learning disabilities

Young adults with severe disabilities and learning difficulties (SLD) have very limited access to appropriate learning resources. Their unique individual needs and requirements prevent them from accessing traditional methods of online learning, and resources tend not to be age appropriate. The majority of SLD learners has difficulty accessing a computer with standard peripherals such as a mouse and relies on assistive technologies (e.g. switches) to do so. Each learner tends to have specific needs that must be addressed in order to provide an accessible and adaptive platform for learning. The aim of this research project was, with the assistance and support of the learners and their tutors, to design and develop an adaptable and inclusive online learning environment specifically catering for the needs of young adults with SLD. Each stage of development was prototyped and assessed in the college environment to ensure the needs of the learners were thoroughly addressed. 1

No evidence for top-down expertise effects on action perception in sprinters using static images.

Athletes have been found to demonstrate a superior ability to detect subtle variations in dynamic displays (e.g., point-light displays and videos) depicting expert actions compared to non-athletes. The current study aimed to determine whether this advantage also exists when dynamic information is unavailable (i.e., using static images). Using a staircase procedure, two frames from a video depicting an athlete either walking (everyday action) or performing a sprint start (expert action) were presented, and athletes (sprinters) and non-athletes were asked to indicate whether the images were identical or different. We examined whether presenting the images sequentially (temporal task) or simultaneously (spatial task) influenced participants' discrimination performance. We predicted that the sprinters would outperform the non-sprinters in the spatial task as body postures could be compared directly but not in the temporal task due to larger representational momentum effects for athletes. Contrary to our hypotheses, the sprinters and non-sprinters performed similarly in all tasks and conditions. In line with the prediction that representational momentum may impair performance, participants' thresholds were lower for the spatial than the temporal task. However, post-hoc analysis suggested that this effect is likely to be better explained by a task order effect whereby participants who completed the temporal task first exhibited an advantage in the spatial task, while there were no performance differences for participants who completed the opposite task order. In sum, our results provide no evidence for the idea that motor expertise affects action perception (i.e., perceptual resonance) in a simple psychophysical task employing static images

Temporal-order judgement task suggests chronological action representations in motor experts and non-experts

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Action Perception in Athletes : Expertise Facilitates Perceptual Discrimination

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Women members and witnesses on British government ad hoc committees of inquiry 1850-1930, with special reference to royal commissions of inquiry.

The thesis describes the participation of women as witnesses and members of British government committees of inquiry during the nineteenth and early twentieth centuries. It examines this participation both from the point of view of the women concerned and of the administrations which appointed them. It seeks to establish that such committee work was a form of political activity for individual women; and, by indicating the extent of the organisations and networks which linked these and similar women, demonstrates the existence of a small group of women working within the political elite who collaborated in the shaping of certain aspects of public policy during this time. The thesis also considers the institutional implications of women's membership of committees by examining governmental and civil service attitudes to their appointments. It attempts to uncover how and why women were chosen, and argues that women's committee participation was instrumental in the formation of ideas about women's political work. In committees women became established as an interest group to be represented in the same way and in much the same proportions as other class or professional groupings. They thus achieved representation through interest rather than through equity, which contributed to enduring precedents for their subsequent political roles after they were granted the franchise. I examine the work of women on committees as the committee form itself evolved to incorporate them and other groups from within and outside the elite social classes, providing a means by which the political nation could expand through slight changes in existing forms. Appointment to an advisory committee is not commonly seen as political representation, but during the proliferation of such committees through the nineteenth century, it offered a means of participation in political life for some of those denied direct representation through the franchise. In Britain women began to be appointed to such committees some thirty years before they were granted a limited franchise in 1918. Through the committee form women were offered a representative voice in a growing but clearly delimited range of issues that were deemed to concern them, broadly within education, social welfare, and employment. However, their achievements were limited both by their confinement to such issues, and by their consistently low numbers on committees. The thesis concludes that women's committee participation was fixed at almost the same time as it began, and that the period of women's most decisive involvement with this form was during the years between about 1908 and the early 1920s

Transformation of a service organisation through participatory action research

The research aimed to pro-activeiy embark in an internal transformation process, in order to improve efficiency of the Social Work Department of Gauteng Medical Command of the South African Military Health Service. Participatory action research as a qualitative research design was- used. The intervention identification process was implemented as a problem-solving technique to direct the process of transformation-change. The research was conducted by a research group often social workers from the South African National Defence Force. The results of the research were the implementation of interventions on identified systems, namely the service delivery system and the performance management system of the Social Work Department of Gauteng Medical Command. The use of particpatorv action research as a process to address problems in an organisation was confirmed. The contribution of the participatory action process to process outcomes, such as empowerment and learning, was also indicated in the findings.Social WorkMA(SS) (Mental Health

Bimanual Grasping adheres to Weber’s Law

Acknowledgments Thomas Schenk was supported by grants from the German Research Foundation (Deutsche Forschungsgemeinschaft: DFG-SCHE 735/2-2 and DFG-SCHE 735/3-2) Funding The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Deutsche Forschungsgemeinschaft (grant numbers DFG-SCHE735/2-2, DFG-SCHE 735/3-2)Peer reviewedPublisher PD