Articles

We investigated how targeted reactivation of cortical memory engrams during sleep influences systems consolidation of contextual fear memory. Using a mouse model of contextual fear conditioning (CFC), we tagged retrosplenial cortex (RSC) neurons activated during learning with channelrhodopsin-2 (ChR2) via a c-Fos-based TRAP system. Twenty-four hours post-training, animals received optogenetic stimulation of these RSC engram cells selectively during non-rapid eye movement (NREM) sleep or REM sleep. Immediately after, hippocampal activity was transiently blocked (muscimol infusion) to test hippocampal dependence. We found that NREM-specific reactivation of RSC engrams preserved contextual fear recall despite hippocampal inactivation, whereas REM stimulation or no stimulation failed to rescue memory. These results indicate that engram reactivation during NREM accelerates the transfer of memory to cortical storage. We present high-level diagrams of experimental workflow and results, and report a timeline of revisions. Abbreviations and keywords are provided. This comprehensive revision addresses all reviewer comments and renders the manuscript submission-ready.

Smartphone use among adolescents has surged globally, reshaping communication and learning patterns, especially in developing countries. However, the implications of such digital habits on students in rural or under-resourced areas remain underexplored. This study aims to examine the patterns of smartphone usage and its effects on learning among high school students in Tarutung, a developing region of North Sumatra, Indonesia. Utilizing a quantitative descriptive approach, data were collected from 358 students using structured questionnaires. The results show that 96.05% of students own personal smartphones regardless of socioeconomic background, with an average daily usage of 4 hours and 45 minutes. While 91.81% believe smartphones support their learning, 25.99% report declining academic performance. Alarmingly, 20.62% of students admitted involvement in cyberbullying activities, highlighting a critical digital risk impacting the school environment and student well-being. The study concludes that although smartphones offer educational benefits, their misuse can lead to negative academic, social, and psychological outcomes. This study recommends digital literacy curricula and structured cooperation between parents and educators to prevent risks while optimizing educational opportunities in smartphone use.

Objective: This study explores the relationship between neighborhood stress and Body Mass Index (BMI) in adolescents, while also examining whether this association differs between Black and White adolescents. Methods: Data from the Adolescent Brain Cognitive Development (ABCD) Study were analyzed using linear regression models to examine the association between neighborhood stress (defined as a composite score based on three items measuring perceived safety and neighborhood fear) and BMI in adolescents, controlling for demographic and socioeconomic variables. We tested models both with and without interaction terms to assess whether race moderated the association. Stratified analyses were conducted to further explore potential differences between Black and White adolescents. Results: A positive association was observed between neighborhood stress and BMI across the overall sample. However, this association was weaker for Black adolescents compared to White adolescents, even after adjusting for potential confounders. Conclusions: The contribution of neighborhood stress to higher BMI in adolescents may vary by race. Our findings suggest that while neighborhood stress is associated with increased BMI, Black adolescents appear to be less affected by these stressors than their White peers. This weaker association could be due to the normalization of stress in environments where it is pervasive (what is common becomes normal) or the presence of other significant risk factors affecting BMI in Black youth, such as poverty, limited food access, food culture, and food deserts. Future research should explore processes of habituation, inoculation, or even sensitization to stress among Black populations, who are often exposed to a wide range of stressors throughout the life course.

Purpose: The aim of this study is to the analysis of the South African history of the culture of teaching and learning. This study was driven by the desire for effective teaching and learning within the South African context. Design / Method / Approach: The information in this research came from outside sources (secondary sources). Journal articles (after peer review), dissertations (both published and unpublished), internet sources, and textbooks were used as informational resources. Findings: Teachers believe they have no say in the development of the educational system but are expected to execute its policies and procedures. Fear of change can lead to inappropriate behaviour. For a country to have globally competent citizens it needs to review its curriculum. South Africa has undergone a substantial educational change since the mid-1990s, but its efforts to implement new curricula have been problematic. After the dawn of democracy, concerns were raised about the decline of a positive culture of teaching and learning, especially in disadvantaged township schools. Theoretical implications: there is a lack of theory on an analysis of the South African history of the culture of teaching and learning. Thus, this study seeks to expand the theory. Practical implications: Findings from this research will advance the science behind the culture of teaching and learning in South Africa. Originality / Value: This research will shed light on the development of South Africa's teaching and learning culture, provide suggestions gleaned from its findings, and point the way toward other avenues of inquiry. Research Limitation & Implications: This research was constrained by the quantity and quality of published secondary sources at the time of writing.