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Pub Date: |
2011-02-00 |
Pub Type(s): |
Journal Articles; Reports - Evaluative |
Peer Reviewed: |
Yes |
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Descriptors:
Animals; Biochemistry; Neurological Organization
Abstract:
Whereas short-term plasticity involves covalent modifications that are generally restricted to either presynaptic or postsynaptic structures, long-term plasticity involves the growth of new synapses, which by its nature involves both pre- and postsynaptic alterations. In addition, an intermediate-term stage of plasticity has been identified that might form a bridge between short- and long-term plasticity. Consistent with that idea, although short-term term behavioral sensitization in "Aplysia" involves presynaptic mechanisms, intermediate-term sensitization involves both pre- and postsynaptic mechanisms. However, it has not been known whether that is also true of facilitation in vitro, where a more detailed analysis of the mechanisms involved in the different stages and their interrelations is feasible. To address those questions, we have examined pre- and postsynaptic mechanisms of short- and intermediate-term facilitation at "Aplysia" sensory-motor neuron synapses in isolated cell culture. Whereas short-term facilitation by 1-min 5-HT involves presynaptic PKA and CamKII, intermediate-term facilitation by 10-min 5-HT involves presynaptic PKC and postsynaptic Ca[superscript 2+] and CamKII, as well as both pre- and postsynaptic protein synthesis. These results support the idea that the intermediate-term stage is the first to involve both pre- and postsynaptic molecular mechanisms, which could in turn serve as some of the initial steps in a cascade leading to synaptic growth during long-term plasticity.
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Pub Date: |
2010-00-00 |
Pub Type(s): |
Journal Articles; Reports - Descriptive |
Peer Reviewed: |
Yes |
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Descriptors:
Social Work; Professional Occupations; Social Values; Poverty; Economic Opportunities; Social Change; Systems Approach; Problem Based Learning; Urban Areas; Research Methodology
Abstract:
This article describes the use of problem-based learning to teach students about the scope and consequences of urban poverty through an innovative cross-curricular project. We illustrate the process, goals, and tasks of the Community Assessment Project, which incorporates community-level assessment, collection and analysis of public data, and social policy analysis and planning. Students in three master's classes (Social Work Research I, Ending Poverty: Models for Social Change and Social Action, and Advanced Social Policy in Aging) worked in self-directed groups to explore the impact of economic insecurity on our most vulnerable clients. The project engaged students, linked research and policy practice, and helped to educate the next generation of social workers about urban poverty and strategies for community-based research and practice. (Contains 2 tables.)
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Pub Date: |
2006-00-00 |
Pub Type(s): |
Journal Articles; Reports - Research |
Peer Reviewed: |
Yes |
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Descriptors:
Inhibition; Stimuli; Habituation; Correlation; Shift Studies; Desensitization; Cytology; Biological Influences; Molecular Biology; Scientific Methodology; Scientific Research
Abstract:
Dishabituation has been thought to be due either to reversal of the process of habituation or to a second process equivalent to sensitization superimposed on habituation. One way to address this question is by testing whether dishabituation and sensitization can be dissociated. Previous studies using this approach in "Aplysia" have come to different conclusions about the nature of dishabituation, perhaps because those studies differed in many respects, including (1) whether they also observed transient behavioral inhibition, and (2) whether they used test stimuli that activated the LE siphon sensory neurons or as yet unidentified sensory neurons. To attempt to resolve the apparent contradictions between the previous studies, we have explored the importance of these two factors by performing a parametric study of dishabituation and sensitization of gill withdrawal in a simplified preparation that does not exhibit transient behavioral inhibition, using two different test stimuli that are known to activate the LE (Touch) or unidentified (Not Touch) sensory neurons. We find that dishabituation and sensitization in this preparation have similar time courses and generally similar functions of shock intensity. However, under one condition, with the Not Touch stimulus 2.5 min after the shock, dishabituation has a reverse effect of shock intensity. Additional analyses suggest that dishabituation with the Not Touch stimulus 2.5 min after the shock is due to reversal of habituation, whereas 12.5 min after the shock, dishabituation is due to superimposed sensitization. These results thus suggest that dishabituation may involve either process in the same preparation, and begin to define the conditions that favor one or the other. (Contains 4 figures.)
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Author(s): |
Hawkins, Robert P.; Pingree, Suzanne; Hitchon, Jacqueline; Radler, Barry; Gorham, Bradley W.; Kahlor, Leeann; Gilligan, Eileen; Serlin, Ronald C.; Schmidt, Toni; Kannaovakun, Prathana; Kolbeins, Gudbjorg Hildur |
Source: |
Human Communication Research, v31 n1 p162-187 Jan 2005 |
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Pub Date: |
2005-01-00 |
Pub Type(s): |
Journal Articles; Reports - Evaluative |
Peer Reviewed: |
Yes |
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Descriptors:
Cognitive Processes; Attention Span; Television Viewing; Individual Differences; Predictor Variables; Programming (Broadcast)
Abstract:
Individual looks at television vary enormously in length, and this has previously indicated differences in ongoing cognitive processes. Furthermore, the relative frequency of looks of different lengths may indicate styles of attention to television. This article compares visual attention of 152 subjects across a variety of genres and examines differences located by situation, person, and media perception variables. Attention style was not consistent for individuals but varied for different types of programming and between-program breaks. Situational, person, and media belief variables did not predict the proportions of four types of looks. They did, however, predict differences in the proportion of moderately short (orienting) looks across types of content, but not the previously more important very short (monitoring) or moderately long (engaged) looks. The overall importance of type of content in these results suggests that further research should examine within-program differences in message construction and assess attentional style as patterns or sequences of looks.
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