672 research outputs found

    Cartoon planet: Micro-reflection through digital cartoons - a case study on teaching and learning with young people

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    The young learners of today tend to show little enthusiasm for formal schooling. This does not necessarily mean pupils are not interested in learning or developing new skills and competences. In fact, the opposite often happens in the informal settings they belong to. Finding ways of transferring pupil’s informal learning to the school setting is therefore important. This paper gives a brief overview on the development of informal learning activities to encourage young people’s active reflection on their informally acquired competencies through the use of web technologies. The researchers also explore the role of the teacher, and the need of a participatory learning environment in a less formal classroom. Reflections on the experiences and recommendations are also provided

    Synapse development is regulated by microglial THIK-1 K+ channels

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    Microglia are the resident immune cells of the central nervous system. They constantly survey the brain parenchyma for redundant synapses, debris, or dying cells, which they remove through phagocytosis. Microglial ramification, motility, and cytokine release are regulated by tonically active THIK-1 K+ channels on the microglial plasma membrane. Here, we examined whether these channels also play a role in phagocytosis. Using pharmacological blockers and THIK-1 knockout (KO) mice, we found that a lack of THIK-1 activity approximately halved both microglial phagocytosis and marker levels for the lysosomes that degrade phagocytically removed material. These changes may reflect a decrease of intracellular [Ca2+]i activity, which was observed when THIK-1 activity was reduced, since buffering [Ca2+]i reduced phagocytosis. Less phagocytosis is expected to result in impaired pruning of synapses. In the hippocampus, mice lacking THIK-1 expression had an increased number of anatomically and electrophysiologically defined glutamatergic synapses during development. This resulted from an increased number of presynaptic terminals, caused by impaired removal by THIK-1 KO microglia. The dependence of synapse number on THIK-1 K+ channels, which control microglial surveillance and phagocytic ability, implies that changes in the THIK-1 expression level in disease states may contribute to altering neural circuit function

    Memory consolidation in the cerebellar cortex

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    Several forms of learning, including classical conditioning of the eyeblink, depend upon the cerebellum. In examining mechanisms of eyeblink conditioning in rabbits, reversible inactivations of the control circuitry have begun to dissociate aspects of cerebellar cortical and nuclear function in memory consolidation. It was previously shown that post-training cerebellar cortical, but not nuclear, inactivations with the GABA(A) agonist muscimol prevented consolidation but these findings left open the question as to how final memory storage was partitioned across cortical and nuclear levels. Memory consolidation might be essentially cortical and directly disturbed by actions of the muscimol, or it might be nuclear, and sensitive to the raised excitability of the nuclear neurons following the loss of cortical inhibition. To resolve this question, we simultaneously inactivated cerebellar cortical lobule HVI and the anterior interpositus nucleus of rabbits during the post-training period, so protecting the nuclei from disinhibitory effects of cortical inactivation. Consolidation was impaired by these simultaneous inactivations. Because direct application of muscimol to the nuclei alone has no impact upon consolidation, we can conclude that post-training, consolidation processes and memory storage for eyeblink conditioning have critical cerebellar cortical components. The findings are consistent with a recent model that suggests the distribution of learning-related plasticity across cortical and nuclear levels is task-dependent. There can be transfer to nuclear or brainstem levels for control of high-frequency responses but learning with lower frequency response components, such as in eyeblink conditioning, remains mainly dependent upon cortical memory storage

    Role of per-oral pancreatoscopy in the evaluation of suspected pancreatic duct neoplasia: a 13-year U.S. singlecenter experience

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    Background and Aims The role of per-oral pancreatoscopy (POP) in the evaluation of occult pancreatic duct (PD) lesions remains limited to case series. The aim of this study was to evaluate the ability of POP to differentiate malignant from benign diseases of the PD. Methods Patients who underwent POP between 2000 and 2013 for the evaluation of indeterminate PD strictures, dilatations, or with suspected or known main duct intraductal papillary mucinous neoplasm were identified. Main outcome measurements were visual impression accuracy, POP tissue sampling, efficacy, and safety of POP. Results During the study period, 79 patients who underwent POP for the evaluation of pancreatic stricture or dilatation were identified. Technical success was achieved in 78 (97%). In the PD neoplasia group (n = 33), the final diagnosis was based on index confirmatory POP-guided tissue sampling in 29 (88%). For the detection of PD neoplasia, POP visual impression had a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 87%, 86%, 83%, 91%, and 87%, respectively. When combined with POP-guided tissue sampling, the values were 91%, 95%, 94%, 93%, and 94%, respectively. Of 102 POPs performed, adverse events were noted in 12 (12%) cases. Conclusions This study demonstrates a high technical success rate, visual impression accuracy, and tissue sampling capability of POP. Examinations were performed by endoscopists with expertise in pancreatoscopy interpretation, and the results may not be generalizable

    Electrical coupling of neuro-ommatidial photoreceptor cells in the blowfly

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    A new method of microstimulation of the blowfly eye using corneal neutralization was applied to the 6 peripheral photoreceptor cells (R1-R6) connected to one neuro-ommatidium (and thus looking into the same direction), whilst the receptor potential of a dark-adapted photoreceptor cell was recorded by means of an intracellular microelectrode. Stimulation of the photoreceptor cells not impaled elicited responses in the recorded cell of about 20% of the response elicited when stimulating the recorded cell. This is probably caused by gap junctions recently found between the axon terminals of these cells. Stimulation of all 6 cells together yielded responses that were larger and longer than those obtained with stimulation of just the recorded cell, and intensity-response curves that deviated more strongly from linearity. Evidence is presented that the resistance of the axon terminal of the photoreceptor cells quickly drops in response to a light flash, depending on the light intensity. Incorporating the cable properties of the cell body and the axon, the resistance of the gap junctions, and the (adapting) terminal resistance, a theoretical model is presented that explains the measurements well. Finally, it is argued that the gap junctions between the photoreceptor cells may effectively uncouple the synaptic responses of the cells by counteracting the influence of field potentials.

    Tuning of Ranvier node and internode properties in myelinated axons to adjust action potential timing

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    Action potential timing is fundamental to information processing;however, its determinants are not fully understood. Here we report unexpected structural specializations in the Ranvier nodes and internodes of auditory brainstem axons involved in sound localization. Myelination properties deviated significantly from the traditionally assumed structure. Axons responding best to low-frequency sounds had a larger diameter than high-frequency axons but, surprisingly, shorter internodes. Simulations predicted that this geometry helps to adjust the conduction velocity and timing of action potentials within the circuit. Electrophysiological recordings in vitro and in vivo confirmed higher conduction velocities in low-frequency axons. Moreover, internode length decreased and Ranvier node diameter increased progressively along the distal axon segments, which simulations show was essential to ensure precisely timed depolarization of the giant calyx of Held presynaptic terminal. Thus, individual anatomical parameters of myelinated axons can be tuned to optimize pathways involved in temporal processing

    Coronavax : preparing community and government for COVID-19 vaccination:: a research protocol for a mixed methods social research project

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    Introduction Ahead of the implementation of a COVID-19 vaccination programme, the interdisciplinary Coronavax research team developed a multicomponent mixed methods project to support successful roll-out of the COVID-19 vaccine in Western Australia. This project seeks to analyse community attitudes about COVID-19 vaccination, vaccine access and information needs. We also study how government incorporates research findings into the vaccination programme. Methods and analysis The Coronavax protocol employs an analytical social media study, and a qualitative study using in-depth interviews with purposively selected community groups. Participant groups currently include healthcare workers, aged care workers, first responders, adults aged 65+ years, adults aged 30-64 years, young adults aged 18-29 years, education workers, parents/guardians of infants and young children (&lt;5 years), parents/guardians of children aged 5-18 years with comorbidities and parents/guardians who are hesitant about routine childhood vaccines. The project also includes two studies that track how Australian state and Commonwealth (federal) governments use the study findings. These are functional dialogues (translation and discussion exercises that are recorded and analysed) and evidence mapping of networks within government (which track how study findings are used). Ethics and dissemination Ethics approval has been granted by the Child and Adolescent Health Service Human Research Ethics Committee (HREC) and the University of Western Australia HREC. Study findings will be disseminated by a series of journal articles, reports to funders and stakeholders, and invited and peer-reviewed presentations.</p
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