Bi-Directional Effect of Cholecystokinin Receptor-2 Overexpression on Stress-Triggered Fear Memory and Anxiety in the Mouse

Fear, an emotional response of animals to environmental stress/threats, plays an important role in initiating and driving adaptive response, by which the homeostasis in the body is maintained. Overwhelming/uncontrollable fear, however, represents a core symptom of anxiety disorders, and may disturb the homeostasis. Because to recall or imagine certain cue(s) of stress/threats is a compulsory inducer for the expression of anxiety, it is generally believed that the pathogenesis of anxiety is associated with higher attention (acquisition) selectively to stress or mal-enhanced fear memory, despite that the actual relationship between fear memory and anxiety is not yet really established. In this study, inducible forebrain-specific cholecystokinin receptor-2 transgenic (IF-CCKR-2 tg) mice, different stress paradigms, batteries of behavioral tests, and biochemical assays were used to evaluate how different CCKergic activities drive fear behavior and hormonal reaction in response to stresses with different intensities. We found that in IF-CCKR-2 tg mice, contextual fear was impaired following 1 trial of footshock, while overall fear behavior was enhanced following 36 trials of footshock, compared to their littermate controls. In contrast to a standard Yerkes-Dodson (inverted-U shaped) stress-fear relationship in control mice, a linearized stress-fear curve was observed in CCKR-2 tg mice following gradient stresses. Moreover, compared to 1 trial, 36 trials of footshock in these transgenic mice enhanced anxiety-like behavior in other behavioral tests, impaired spatial and recognition memories, and prolonged the activation of adrenocorticotropic hormone (ACTH) and glucocorticoids (CORT) following new acute stress. Taken together, these results indicate that stress may trigger two distinctive neurobehavioral systems, depending on both of the intensity of stress and the CCKergic tone in the brain. A “threshold theory” for this two-behavior system has been suggested

Conceptualising pedagogical designs for learning through object-oriented collaboration in higher education

Abstract This paper elaborates on the notion of object-oriented collaborative learning by building on empirical material from two case studies in higher education. Prior empirical findings show how knowledge objects are evolving entities, shaped by the interactions between participants, and how students learn from engaging in knowledge practice that involves different activities with knowledge objects. However, the pedagogy of teaching and learning with objects needs to be further explored and grounded in empirical data. Using two case studies, we examine how learning designs in higher education courses support students’ learning through work on shared knowledge objects, as well as how students experience these designs and the learning process. By means of complementary datasets, the learning design, enacted teaching practices, collaboration processes, experiences, and competence learned are mapped and analysed. The findings are helpful in elucidating the learning taking place through interaction and practices mediated by shared knowledge objects, as well as informing the development of principles of a pedagogy of object-oriented collaborative learning, which provide practical recommendations and invite further research endeavours

INTRODUCTION

The range of theoretical approaches, techniques, and methodologies applied in research on learning and instruction is constantly enriched, generating a diverse and continuously evolving research environment. Conceptual and methodological diversity and developments that can bring about new ways of theorising and of using theory and methods to examine learning and education are essential for the field’s advancement. Bagga-Gupta’s contribution discusses alternatives to current hegemonic North/Euro-centric theorising in research on communication, diversity, and culture in learning and education. Complementarity should be considered both in terms of potential combinations of concepts as well as methods drawn from different traditions as resources to promote theoretical and methodological development. It is also salient in the acknowledgement of the fact that each theoretical-methodological approach offers a unique perspective on education and learning, rendering visible the relevant dimensions of education and learning that may remain invisible when other approaches are adopted