Electrophysiological Heterogeneity of Fast-Spiking Interneurons: Chandelier versus Basket Cells

In the prefrontal cortex, parvalbumin-positive inhibitory neurons play a prominent role in the neural circuitry that subserves working memory, and alterations in these neurons contribute to the pathophysiology of schizophrenia. Two morphologically distinct classes of parvalbumin neurons that target the perisomatic region of pyramidal neurons, chandelier cells (ChCs) and basket cells (BCs), are generally thought to have the same "fast-spiking" phenotype, which is characterized by a short action potential and high frequency firing without adaptation. However, findings from studies in different species suggest that certain electrophysiological membrane properties might differ between these two cell classes. In this study, we assessed the physiological heterogeneity of fast-spiking interneurons as a function of two factors: species (macaque monkey vs. rat) and morphology (chandelier vs. basket). We showed previously that electrophysiological membrane properties of BCs differ between these two species. Here, for the first time, we report differences in ChCs membrane properties between monkey and rat. We also found that a number of membrane properties differentiate ChCs from BCs. Some of these differences were species-independent (e.g., fast and medium afterhyperpolarization, firing frequency, and depolarizing sag), whereas the differences in the first spike latency between ChCs and BCs were species-specific. Our findings indicate that different combinations of electrophysiological membrane properties distinguish ChCs from BCs in rodents and primates. Such electrophysiological differences between ChCs and BCs likely contribute to their distinctive roles in cortical circuitry in each species. © 2013 Povysheva et al

Inter- and intra-observer variability in Sonographic measurements of the cross-sectional diameters and area of the umbilical cord and its vessels during pregnancy

Background. The purpose of the study was to evaluate inter- and intra-observer variability in sonographic measurements of the cross-sectional area of the umbilical cord and the diameters of its vessels in low-risk pregnancies of 12 to 40 weeks of gestation. Methods. A prospective cross sectional study was performed in 221 pregnant women at different gestational ages. Measurements were carried out also by a second observer to evaluate inter-observer variability and repeated once again by the first observer to assess intra-observer variability. The linear correlation between the measurements (Spearman's coefficient of correlation) and their reliability through the intraclass correlation coefficient (ICC), the Cronbach's alpha coefficient and the limits of agreement proposed by Bland and Altman were evaluated. Results. The results showed that inter-observer and intra-observer variability did not show any significant difference between examiners. A good linear correlation between the measurements and reliability was obtained, with values of R, ICC and Cronbach's alpha all above the standard limits. Conclusion. It is possible to conclude that inter- and intra-observer variability in the measurements of the umbilical cord and its vessels was small; their reliability and agreement were good. © 2008 Barbieri et al; licensee BioMed Central Ltd

Guideline for organizing content in adaptive learning system

In the past few years, various adaptive learning systems were developed in response to a widespread desire for all encompassing educational environments. However, these learning systems were developed by educational researchers using various techniques thereby resulting in varying outcomes. This is so because there is no specified guideline that leads to the development of an efficient and effective online adaptive learning system. Therefore, the need to propose guidelines for organizing content in an online adaptive learning system that will cater for all learners regardless of their differences. Several databases and keywords were used to ascertain the lack of guidelines in organizing content in adaptive learning systems. In this study, we propose a content adaptation guidelines for different type of learners in online adaptive learning systems based on Martinez learning style model as employing the same instructional conditions to all students can be pedagogically inefficient. The guideline is developed on the adaptation mapping from information in the student model which is carried out in four stages Organizing content, Individualized content, Adaptive navigation and Control level. These guidelines will help developers as well as educators with basic steps in developing a seamless online adaptive learning system for different type of learners

Comparing the Effect Size of School Level Support on Teachers’ Technology Integration

Teachers are expected to lead the innovative use of Information Communication and Technology (ICT) at the classroom level of context. However, research literature shows that a number of factors influence their ICT pedagogical practices. Therefore, the present study investigates the influence of school level support on teacher educators’ technology integration. A mixed method is used to collect data through three focused interviews (N = 19) and self-completion survey (N = 136). The data collected is analysed both qualitatively and quantitatively. The result shows support for the model hypothesized and suggests that the ICT pedagogical practices of the teacher educators do not predict their technology integration. Also, there was evidence that the school level context influenced teachers’ ICT competence, which is necessary for successful technology integration.peerReviewe