It is assumed that plasticity involving up-and down regulation of synaptic strength (i.e., long-term potentiation, LTP; long-term depression, LTD) mediates learning and memory processes. Typically, high-frequency stimulation (HFS) of afferent fibers results in LTP, while low-frequency stimulation (LFS) elicits LTD. In stark contrast to this “HFS- LTP vs. LFS-LTD” dogma, the present thesis characterizes a novel form of LFS-induced LTP in the septohippocampal system. The first set of experiments show that alternating, single pulse stimulation (1 Hz) of the medial septum (MS) and CA3 hippocampal (H) commissural fibres results in a long-lasting potentiation of field excitatory postsynaptic potentials (fEPSPs) in CA1 of urethane-anesthetised rats (MS-H-LTP). MS-H LTP is long lasting (>5 h), requires a specific inter-stimulus interval of 1 s between MS and CA3 stimulation, saturates with repeated stimulation episodes and depends on NMDA receptor activation. In the third chapter (review) I suggest that LFS protocols may more accurately mimic some oscillatory activity patterns (~ 1Hz) present in hippocampal and neocortical circuits during sleep-related memory consolidation. Moreover, I compare the mechanisms underlying classical, HFS-LTP to those mediating MS-H LTP as well as several other types of LFS-LTP in the hippocampus and amygdala in vitro. Subsequently, I investigated cellular mechanisms of MS-H LTP and their similarity to classical HFS-LTP via drug application at the CA1 recording site and showed that MS-H LTP depends on protein kinase A and protein synthesis. This surprising similarity between mechanisms mediating HFS-LTP and MS-H LTP was further supported by occlusion experiments whereby LFS and HFS, delivered to the same animal, competed for the available synaptic potentiation of CA3-CA1 synapses. The final experiments showed that MS-H LTP is compromised in early aged rats, while similar levels of potentiation are expressed in the juvenile and adult hippocampus. Interestingly, MS-H LTP could not be induced (i.e., was occluded) 3 h after training on the hidden platform version of the Morris water maze, while it was unaltered at 8 and 24 h intervals. This thesis characterizes a novel form of hippocampal plasticity at the cellular, synaptic and behavioural level and suggests that LFS-LTP may mediate processes of sleep-related memory consolidation. / Thesis (Ph.D, Neuroscience Studies) -- Queen's University, 2010-10-04 11:35:21.288

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The meaning of ‘home’ for older adults in long-term care (LTC) settings is not well understood. Furthermore, how living with cognitively impaired older adults may affect the meaning of ‘home’ is under researched. The goal of this study was to explore how living with cognitively impaired older adults affects the meaning of ‘home’ for cognitively well female older adults residing in LTC. A convenience sample of eleven female cognitively well older adults was selected from four LTC settings in Winnipeg, Manitoba, Canada. The eleven women were interviewed to determine their meaning of ‘home’ prior to and following placement in the LTC setting. Two key questions posed to the women were, “Do you consider (name of LTC setting) to be ‘home’?” and “How does living with confused people affect the meaning of home?” Eight of the women considered the LTC setting where they reside to be ‘home’. Nine of the women indicated that living with cognitively impaired older adults does not affect their meaning of ‘home’. These findings suggest two things. First, that most cognitively well female older adults create a new ‘home’ for themselves when they move to the LTC setting. Second, that many cognitively well female older adults demonstrate compassion and acceptance of living with fellow residents who have cognitive impairment and may exhibit disruptive behaviours.

International education has been a growing trend globally over the past thirty years. Since the late 1980s, the popularity of study abroad programme amongst Japanese students has also seen a significant increase following the international education trend. A more recent trend in international education has been the development of shorter term study abroad programmes and the value of these programmes has been widely recognised in Japan. In response to Japanese government initiatives, Japanese secondary schools have developed short-term programmes in order to develop students’ international awareness. As a result, a large number of Japanese high school students have participated in a short-term study abroad programme in the last 20 years. Japan and New Zealand have a long history of sister school relationships. By 2012, 191 Japanese high schools had established sister school relationships, and these school links have provided the impetus for exchange programmes; which means that many Japanese high school students visit New Zealand schools to study in short-term programmes (for less than 3 months) or longer. Several scholars have investigated the learners’ outcomes of the short-term study abroad of university students. From their studies, it has been established that the main learning objectives of study abroad programmes, are second language acquisition, intercultural competence and personal development. However, little is yet known about the outcomes of younger students who have participated in short-term programmes; only a few attempts have so far been made to analyse the case of Japanese secondary school students’ short-term programmes, and few still refer specifically to programmes in New Zealand. One of my main objectives was to determine a) what were the objectives of Japanese secondary students to participation in a short-term study abroad programme in New Zealand, b) whether they feel satisfied that their objectives have been. Also, as other researchers mentioned, could benefits such as second language acquisition, intercultural competence and personal development be claimed by secondary schools participating in these programmes – specifically the Darfield High School short-term programme that is my case study. In order to do this, I conducted two surveys with four different groups of Japanese secondary school students who visited Darfield High School from 2009 to 2012 as a case study. The findings suggest that many Japanese secondary school students expected to improve their English conversation skills, but they did not feel much improvement in this area after the programme, however, upon reflection, after the programme, students recognised that they had gained far more than they had expected in a general sense. For example, many participants expected to learn about some of the aspects of New Zealand culture as a result of the programme and indeed many students felt that they accomplished this objective, in addition to learning more about their own culture. It is anticipated that the results of my research will assist those who organise study abroad programmes, assist students to maximise their learning, and benefit organisations who host students from overseas.

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No description available.

The meaning of ‘home’ for older adults in long-term care (LTC) settings is not well understood. Furthermore, how living with cognitively impaired older adults may affect the meaning of ‘home’ is under researched. The goal of this study was to explore how living with cognitively impaired older adults affects the meaning of ‘home’ for cognitively well female older adults residing in LTC. A convenience sample of eleven female cognitively well older adults was selected from four LTC settings in Winnipeg, Manitoba, Canada. The eleven women were interviewed to determine their meaning of ‘home’ prior to and following placement in the LTC setting. Two key questions posed to the women were, “Do you consider (name of LTC setting) to be ‘home’?” and “How does living with confused people affect the meaning of home?” Eight of the women considered the LTC setting where they reside to be ‘home’. Nine of the women indicated that living with cognitively impaired older adults does not affect their meaning of ‘home’. These findings suggest two things. First, that most cognitively well female older adults create a new ‘home’ for themselves when they move to the LTC setting. Second, that many cognitively well female older adults demonstrate compassion and acceptance of living with fellow residents who have cognitive impairment and may exhibit disruptive behaviours.

No description available.

Previous studies of how working memory (WM) capacity affects lexical ambiguity resolution have been inconclusive about the choice between inhibition and activation comprehension strategies. In contrast, an adaptive inhibition hypothesis suggests that this choice depends on the availability of WM resources. We used a cross-modal semantic priming paradigm. Participants listened to sentences biasing the subordinate meanings of homonyms, presented at a fast or slow speech rate. We measured lexical decision response latencies to target words that were related to either the subordinate or dominant meaning of homonyms. A WM test was used to evaluate participants' WM capacity. At a fast rate, both high and low WM participants activated dominant (or irrelevant) meanings of the subordinate-biased homonyms. At a regular rate, participants with low WM capacity activated dominant meanings; however, participant with high WM inhibited them. Thus, people with high WM activate and inhibit alternative meanings more flexibly than people with low WM.

Two dual task experiments were conducted to determine the function and content of working memory in concept attainment. Levine's (1966) concept attainment paradigm was used as the primary task. The secondary task in each experiment made selective demands on one of two working memory components, either the phonological loop or the central executive. The effect of the secondary tasks on the performance on the Levine task was measured by frequency of hypothesis use, consistency of hypotheses with previous feedback, and strategies employed to manage feedback. These measures revealed that the two working memory components play different roles in concept attainment. The phonological loop is responsible for maintaining hypotheses, while the central executive carries out mental operations that enable the use of hypotheses that are logically consistent with the given feedback. These findings make it possible to provide a detailed account of the role of working memory in concept attainment and yield new insights into the concept attainment process.