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The real world is full of noise and constantly overlapping sounds. However, our auditory system provides a solution to this, that is, the continuity illusion; when we hear a sound stream that is partially replaced by high‐level noise, we can restore missing sound information and "fill in" the information as if it were smooth and continuous even against a background of noise. In the present study, we tested the preferences for familiar and novel melodies of 8‐month‐old infants after a 2‐month memory retention interval following 1‐week exposure to a specific melody. A preference for familiarity was seen not only when the melody was presented intact but also when it was periodically replaced by high‐level noise, which elicits the continuity illusion in adults (Experiment 1). However, a trend toward preference for a novel melody was observed for stimuli periodically replaced by low‐level noise that did not satisfy the ecological constraints for the elicitation of the illusion (Experiment 2). For the first time, this study showed that infants as young as 8 months of age are susceptible to the auditory continuity illusion. The study also revealed that the infants could recognize the melody they heard 2 months previously. [ABSTRACT FROM AUTHOR]

Introduction: Repetitive somatosensory stimulation (RSS) is a conventional approach to modulate the neural states of both the primary somatosensory cortex (S1) and the primary motor cortex (M1). However, the impact of RSS on skill acquisition and retention in sensorimotor adaptation remains debated. This study aimed to investigate whether whole-hand water flow (WF), a unique RSS)induced M1 disinhibition, influences sensorimotor adaptation by examining the hypothesis that whole-hand WF leads to M1 disinhibition; thereby, enhancing motor memory retention. Methods: Sixty-eight young healthy participants were randomly allocated to three groups based on the preconditioning received before motor learning: control, whole-hand water immersion (WI), and whole-hand WF. The experimental protocol for all the participants spanned two consecutive days. On the initial day (day 1), baseline transcranial magnetic stimulation (TMS) assessments (T0) were executed before any preconditioning. Subsequently, each group underwent their respective 30  min preconditioning protocol. To ascertain the influence of each preconditioning on the excitability of the M1, subsequent TMS assessments were conducted (T1). Following this, all participants engaged in the motor learning (ML) of a visuomotor tracking task, wherein they were instructed to align a cursor with a target trajectory by modulating the pinch force. Upon completion of the ML session, final TMS assessments (T2) were conducted. All participants were required to perform the same motor learning 24  h later on day 2. Results: The results revealed that whole-hand WF did not significantly influence skill acquisition during sensorimotor adaptation, although it did reduce intracortical inhibition. This phenomenon is consistent with the idea that S1, rather than M1, is involved in skill acquisition during the early stages of sensorimotor adaptation. Moreover, memory retention 24  h after skill acquisition did not differ significantly across the three groups, challenging our initial hypothesis that whole-hand WF enhances memory retention throughout sensorimotor adaptation. This could be due to the inability of whole-hand WF to alter sensorimotor connectivity and integration, as well as the nature of the plastic response elicited by the preconditioning. Discussion: In conclusion, these findings suggest that although whole-hand WF attenuates intracortical inhibition, it does not modulate skill acquisition or motor memory retention during sensorimotor adaptation. [ABSTRACT FROM AUTHOR]

Motor learning is a prominent and extensively studied subject in rehabilitation following various types of neurological disorders. Motor repair and rehabilitation often extend over months and years post-injury with a slow pace of recovery, particularly affecting the fine movements of the distal extremities. This extended period can diminish the motivation and persistence of patients, a facet that has historically been overlooked in motor learning until recent years. Reward, including monetary compensation, social praise, video gaming, music, and virtual reality, is currently garnering heightened attention for its potential to enhance motor motivation and improve function. Numerous studies have examined the effects and attempted to explore potential mechanisms in various motor paradigms, yet they have yielded inconsistent or even contradictory results and conclusions. A comprehensive review is necessary to summarize studies on the effects of rewards on motor learning and to deduce a central pattern from these existing studies. Therefore, in this review, we initially outline a framework of motor learning considering two major types, two major components, and three stages. Subsequently, we summarize the effects of rewards on different stages of motor learning within the mentioned framework and analyze the underlying mechanisms at the level of behavior or neural circuit. Reward accelerates learning speed and enhances the extent of learning during the acquisition and consolidation stages, possibly by regulating the balance between the direct and indirect pathways (activating more D1-MSN than D2-MSN) of the ventral striatum and by increasing motor dynamics and kinematics. However, the effect varies depending on several experimental conditions. During the retention stage, there is a consensus that reward enhances both short-term and long-term memory retention in both types of motor learning, attributed to the LTP learning mechanism mediated by the VTA-M1 dopaminergic projection. Reward is a promising enhancer to bolster waning confidence and motivation, thereby increasing the efficiency of motor learning and rehabilitation. Further exploration of the circuit and functional connections between reward and the motor loop may provide a novel target for neural modulation to promote motor behavior. [ABSTRACT FROM AUTHOR]

Honey bees may experience the adverse effects of environmental contaminants when exposed during foraging trips, or something to that effect. We hypothesized that octopamine (OA), with important functions in reward signaling and learning, can improve the behavior of honey bees under chemical stress. Memory retention and sucrose responsiveness were evaluated using the proboscis extension reflex (PER) assay. The one-day-old bees were exposed separately to diazinon, imidacloprid, paraquat, manganese, and thymol at concentrations of 0.22, 29.04, 55.69, 106.19, and 0.91 ppm, respectively. On the 21st day of exposure, the bees' responses to memory retention and sucrose responsiveness experiments were recorded after the training trial. In addition, PERs were recorded after OA injection. During the intervals, honey bees were exposed to the toxins topically. The expression levels of OA receptor genes, AmoctαR1 and AmoctβR4, were measured. The sucrose responsiveness tests showed no significant differences between the bees stimulated with the control solutions or toxins. Moreover, our results indicated that memory retention significantly declined in honey bees exposed to toxins compared to the controls (P ≤ 0.05). According to the findings, OA improved the memory retention of honey bees exposed to toxins (P ≤ 0.05). The expression levels of AmoctαR1 and AmoctβR4 genes significantly increased in the treated honey bees, especially those exposed to paraquat and manganese, after 30 min post-OA injection. It can be concluded that under chemical stress, OA administration encouraged honey bees to respond to a stimulus. Therefore, it can be added to a nutrient-enriched diet. [ABSTRACT FROM AUTHOR]

Our empirical research delved into how this interactive digital learning module affected students' learning outcomes and their ability to retain information. We explored three distinct scenarios: an e-learning environment with the interactive digital learning module, an electronic learning module without interactive video, and a traditional classroom environment with a text-based module. This study was conducted with a sample of 180 eleventh-grade students from a senior high school. The results of the experiment revealed that students in the e-learning environment, which incorporated the interactive digital learning module, demonstrated significantly better learning outcomes and retention compared to those in the other settings. Conversely, students who utilized the electronic learning module featuring noninteractive video did not exhibit any notable improvements. These findings suggest that the integration of interactive modular teaching into the learning process enhances student retention, thereby positively influencing their overall learning performance. [ABSTRACT FROM AUTHOR]

Recent studies suggest sharks cognitive abilities are comparable to other vertebrates such as mammals and birds, but we still know relatively little about the long-term memory capacity of sharks. We took advantage of the COVID-19 anthropause to determine whether bull sharks conditioned at a provisioning ecotourism site in Fiji would remember the site after an 18-month hiatus in shark feeding activities. We hypothesized that if bull sharks remembered the food rewards associated with divers at the site, they would return to the reactivated site more rapidly than the original recruitment process that occurred when the site was first established in, 2015. We assumed that original recruitment to the newly established site represent a period of learning and conditioning, whereas a significantly faster recolonization of the site would imply memory recall of the original conditioning. We monitored bull shark abundance at the site for three years (1018 dives) from its original establishment in 2015 until all feeding and diving activities were ceased for 18 months in December, 2020. When shark feeding resumed, we documented bull sharks returning to the site over a three-week period (45 dives beginning June 22, 2022) and compared observed abundances with modelled predictions assuming no interruption to provisioning. Results revealed a rapid return to 'business as usual', suggesting that bull sharks still remembered the food reward conditioning despite an 18-month hiatus in provisioning. This supports the existence of long-lasting cognitive capacities in this species and highlights their relevance for managing activities that could disrupt their natural ecology. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the effect of moderate aerobic exercise on memory retention of 1st-year Political Science students at the University of Cebu Main- Campus, Academic Year 2022-2023. It utilized the quantitative research method; thus, this study used a quasi-experimental pre-test and post-test design. The researchers used this design in conducting this study to evaluate if the intervention known as moderate aerobic exercise, precisely the brisk walk-in-place exercise, positively affects the students' memory retention. Moreover, this research design helps determine the effect of the treatment on the respondents before and after manipulation. Physical exercise has undeniably positive effects on both our bodies and minds. The scientific literature emphasizes its impact on our memory. The idea that something as simple as exercise, which anyone can do, has the potential to improve our memory is reason enough to investigate further. This will be especially beneficial for students, as having a good memory is a requirement for academic success. They chose them as the respondents in this study because their major requires much memorization, and they recently switched from online to face-to-face classes. This research aims to see if there is a difference in students' memory retention before and after moderate aerobic exercise. The research was motivated by the recognized positive influence of physical exercise on memory. It focused on its relevance to students who require strong memorization skills for academic success, especially considering the transition from online to in-person classes. The primary objective was to examine any variations in memory retention before and after moderate aerobic exercise. Individuals were given the challenge of memorizing 50 pairs of words within a ten-minute time frame. This task was repeated on the second, third, and fourth days, and a memory retention test was administered on the fifth day. While the overall results did not reveal a significant difference in memory recall, some participants showed modest improvements, suggesting potential benefits for certain students. The study recommends that future investigations consider factors such as IQ levels, learning preferences, diet, sleep duration, and life stressors, which could influence students' memory abilities. [ABSTRACT FROM AUTHOR]

Optoelectronic devices based on optically responsive materials have gained significant attention due to their low cross talk and reduced power consumption. These devices rely on light‐induced changes in conductance states, which are used to create synaptic weights for image recognition tasks in neural networks. However, a major drawback of such devices is the rapid decay of conductance states after light stimulus removal, which hinders their long‐term memory and performance without a continuous external stimulus in place. To address this issue, a platform neural network scheme is proposed to counter the natural decay of conductance in optoelectronic devices. The approach restores the memory effect of the devices and significantly enhances their performance by several orders of magnitude without using additional energy‐intensive techniques like training pulses or gate fields. Herein, the model is validated experimentally using optoelectronic devices fabricated with two different materials, BP and doped In2O3, and demonstrates the restoration of memory/image retention ability to any material system being studied for optoelectronic synapses and vision. This approach has important implications for the practical application of neuromorphic visual processing technologies, bringing them closer to real‐world applications. [ABSTRACT FROM AUTHOR]

The study Perceived Impact of Multimedia Tools on Ilesa West Secondary School Students Learning of English Language Concepts. The study is a descriptive study; a total number of 300 respondents were used. The instrument for data collections was inventory and was inventory and was structured by the researcher for data collection and reliability level was 0.75. Data collected were analyzed using descriptive statistics specifically mean, standard deviation, frequency counts and Person Product Moment Correlation (PPCM). The findings of the study revealed that Multimedia tools enable you to gain better understanding of English Language concepts that are unclear to you, Multimedia tools give you rom to receive an answer at the same time, as well as being able to exchange responses to questions with teachers in real time, Multimedia tools encourage you to share our thought and opinion on English Language concepts, Multimedia tools develop your critical thinking skills and enrich your learning experience in learning English Language concepts, Multimedia tools help to develop your language skills chiefly English Language, Multimedia tools assist you in comprehending text by utilizing prior knowledge new terminology, Does the appealing features of the multimedia tools allow you to boost your stimulation to the learning process involved in learning English Language concepts, application of multimedia tools in learning English Language also improve memory retention, learning accomplishment and satisfaction. Also, the study has revealed that there is significant difference in learning effectiveness of student who learned English Language concept with multimedia tools and those who learn without it. It also revealed that there is a significant difference in the attitude of secondary school students to learning English Language concepts when multimedia tools are explored and when not. As a result of the findings in this study, this can strengthen the literatures of Multimedia tools. [ABSTRACT FROM AUTHOR]

Adult neurogenesis generates new functional neurons from adult neural stem cells in various regions, including the subventricular zone (SVZ) of the lateral ventricles and subgranular zone (SGZ) of hippocampal dentate gyrus (DG). Available evidence shows hippocampal neurogenesis can be negatively or positively regulated by dietary components. In a previous study, we reported that curcumin (diferuloylmethane; a polyphenolic found in curry spice) stimulates the proliferation of embryonic neural stem cells (NSCs) by activating adaptive cellular stress responses. Here, we investigated whether subchronic administration of curcumin (once daily at 0.4, 2, or 10 mg/kg for 14 days) promotes hippocampal neurogenesis and neurocognitive function in young (5-week-old) mice. Oral administration of low-dose curcumin (0.4 mg/kg) increased the proliferation and survival of newly generated cells in hippocampus, but surprisingly, high-dose curcumin (10 mg/kg) did not effectively upregulate the proliferation or survival of newborn cells. Furthermore, hippocampal BDNF levels and phosphorylated CREB activity were elevated in only low-dose curcumin-treated mice. Passive avoidance testing revealed that low-dose curcumin increased cross-over latency times, indicating enhanced memory retention, and an in vitro study showed that low-concentration curcumin increased the proliferative activity of neural progenitor cells (NPCs) by upregulating NF1X levels. Collectively, our findings suggest that low-dose curcumin has neurogenic effects and that it may prevent age and neurodegenerative disease-related cognitive deficits. [ABSTRACT FROM AUTHOR]

Program comprehension is a continuously important topic in computer science since the spread of personal computers, and several program comprehension models have been identified as possible directions of active code comprehension. There has been little research on how much programmers remember the code they have once written. We conducted two experiments with a group of Computer Science MSc students. In the first experiment, we examined the code comprehension strategies of the participants. The students were given a task to implement a minor feature in a relatively small C++ project. In the second experiment, we asked the students 2 months later to complete the same task again. Before starting the clock, we asked the students to fill a questionnaire which aimed to measure program code-related memory retention: we inquired about how much the students remembered the code, down to the smallest relevant details, e.g. the name of functions and variables they had to find to complete the task. After the second experiment, we could compare the solution times of those students who participated in both parts. As one result, we could see that these students could solve the task in shorter time than they did in the first experiment. We also looked at the results of the questionnaire: the vast majority of students could not precisely remember more than two or three identifiers from the original code. In this paper, we will show how this result compares to the forgetting curve. [ABSTRACT FROM AUTHOR]

Learning to write in English as a Foreign Language (EFL) has always been an issue for most learners since it requires intensive cognitive activity along with language proficiency. This mixed-methods study aimed to examine if interactive Video Embedded Infographics (VEI) could ease this process in a flipped classroom setting compared to traditional infographics. Twenty-four EFL learners equally divided into two groups as traditional infographics group and the video embedded infographics group participating in a 3-week intensive EFL writing training. Quantitative data was obtained through quizzes, a final exam, and a delayed exam, while semi-structured interviews were implemented to obtain qualitative data. Quantitative results showed no significant difference between groups in terms of test performance, indicating satisfactory scores for both groups. Qualitative findings revealed a positive tendency towards video embedded infographics, most learners found them concise, easy to use, and more compact. Participants also showed positive attitudes towards EFL writing courses in a flipped classroom setting, stating that they found it more practical, stress-free, and efficient compared to traditional EFL writing classrooms. [ABSTRACT FROM AUTHOR]

The mechanism of size constancy assures that an object is perceived to be constant in size despite that its retinal size varies with viewing distance. Conversely, an object can be perceived as illusorily larger if the perceived distance becomes greater, due to the size–distance scaling mechanism. The present study aimed at exploring how size–distance scaling is modulated by the encoding duration and how its memory is affected by the retention duration. In Experiment 1, we presented two stimuli simultaneously at two stereoscopic depth planes and manipulated the presentation duration, and found that the magnitude of the size scaling increased with presentation duration. In Experiment 2, we examined the maintenance of size–distance scaling when component stimulus was kept in working memory with variable delays. The results showed that the size scaling was reliably retrieved from working memory if there was no disparity manipulation on the to-be-memorized item, but it decreased with retention if a disparity was applied to the to-be-memorized item. The findings suggest that although the post-scaling size can be stored in working memory, the scaling mechanism may still be in effect when there were conflicts in the oculomotor cues and disparity cues that produces depth perception. [ABSTRACT FROM AUTHOR]

The teaching of Mathematics – in particular, Geometry, through conventional methods has been a challenging task for tutors. Augmented Reality (AR) based applications available in commercial space, have not followed any structured pedagogical approach in the designing process, and also do not ensure that the learning time of students is spent prolifically. In this paper, we explore the use of AR in mathematics for geometry education, to aid visualization of multidimensional objects and long-term retention of concepts by the learners. For designing an appropriate AR application it is necessary to identify some principles which support better memory retention of the students. The application has been specifically designed on the basis of identified principles affecting memory retention. We further explain the development of an AR-based Geometry Learning Assistant (AR-GLA), using a structural approach to pedagogical-design for teaching 3-dimensional geometry to higher school students through improved visualization and enhance their memory retention for related concepts. A sample of 54 K-12 students and 2 teachers with expertise in mathematics were part of the experiment. The students were divided into two different groups; one of the groups was taught with AR-based content whereas the other group was given Interactive Simulation (IS) based learning. The results illustrated that AR-based learning provides better retention of memory as compared to IS-based learning were tested over a period of two months. [ABSTRACT FROM AUTHOR]

Organic artificial synapses are becoming the most desirable format for neuromorphic computing due to their highly tunable resistive states. However, repressively low analog switching range, inferior memory retention, and operational instability greatly hinder the further development of organic synapses. Herein, two donor‐acceptor copolymers consisting of electron‐deficient isoindigo coupled with variable donating moieties for three‐terminal organic synaptic transistors (TOSTs) are reported. It is found that the synaptic function and device stability of TOSTs are significantly improved by enhancing the electron‐donating strength of donor units. Polymer alkylated isoindigo‐bis‐ethylenedioxythiophene exhibits high analog switching range of 170 ×, two orders of magnitude higher than that of normal organic neuromorphic devices. They also demonstrate excellent memory retention of over 5 × 103 s, low switching energy of 13 fJ, and ultrahigh operational stability with 99% of its original current after 100 000 write‐read events in air. Furthermore, the high viability of strong donor strategy is showcased by demonstrating flexible TOSTs with stable synaptic function after repeated mechanical bending as well as organic synapses capable of simulating image information processing. Overall, this work highlights the advantages of the strong donor functionalization strategy to boost the synaptic performance and device stability of TOSTs. [ABSTRACT FROM AUTHOR]

Silk protein products have been used for a wide range of applications. This review focuses on the studies conducted relative to cognitive functions with silk fibroin enzyme hydrolysates (FEH) in humans and animals. All known studies reported in PubMed and Google Scholar have been included. Studies have been conducted on children, high school and college students, adults and seniors, ranging in ages from 7–92 years. Doses of 200–600 mg silk FEH per day for three weeks to 16 weeks have been used. Based on these studies, it can be concluded that silk FEH exhibit beneficial cognitive effects with respect to memory and learning, attention, mental focus, accuracy, memory recall, and overall memory and concentration. These conclusions are supported by studies in rats and mice. Mechanistic studies that have been conducted in animals and cell culture systems are also reviewed. These studies indicate that silk FEH exerts its positive effects on memory and learning by providing neuroprotection via a complex mechanism involving its potent antioxidant and inflammation-inhibiting activities. Acetylcholine (ACh) is secreted by cholinergic neurons, and plays a role in encoding new information. Silk FEH were shown to decrease the levels of the pro-oxidant and pro-inflammatory mediators interlukin-1 (IL-1β), IL-6 and tumor necrosis factor-alpha (TNF-α), protecting the cholinergic system from oxidative stress, thus enhancing ACh levels in the brain, which is known to promote cognitive functions. In addition, the expression of brain-derived neurotrophic factor (BNDF), which is involved in the survival of neurons, is enhanced, and an increase in the expression of the phosphorylated cAMP response element-binding protein (p-CREB) occurs, which is known to play a positive role in cognitive functions. No adverse effects have been reported in association with the use of silk FEH. [ABSTRACT FROM AUTHOR]

Metalâ€"ferroelectricâ€"insulatorâ€"semiconductor (MFIS) capacitors were characterized to elucidate the optimum design schemes for the ferroelectric field-effect transistor applications. The Hf1âˆ' x Zr x O2 (HZO) thin films (18 nm) were prepared on the SiO2 and ZrO2 insulator layers (ILs) with different film thicknesses. The choice of 10 nm thick ZrO2 IL was found to be an optimum condition to properly balance between the values of electric fields applied to the HZO (E HZO) and ZrO2 (E IL) layers, leading to effective improvement in capacitance coupling ratio and to suppression of charge injection for the MFIS capacitors. Furthermore, the crystalline natures of the crystallized HZO films were also found to be strategically controlled on the ZrO2 ILs, which can additionally enhance the E HZO with reducing the E IL. As consequences, the MFIS capacitors using 10 nm thick ZrO2 IL exhibited the ferroelectric memory window as large as 2.5 V at an application of ±5 V, which corresponds to 2.7 times wider value, compared to that obtained from the device using 2 nm thick SiO2 IL. Long-time memory retention and robust program endurance were also verified for the fabricated MFIS capacitors. [ABSTRACT FROM AUTHOR]

The present work examines the effectiveness and possible limitations of the lexical approach in the process of teaching and learning vocabulary. The authors suggest ways to solve the issues of this approach that arise during its application, while maintaining its main advantages, by using Song-Based Approach in a foreign language classroom. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess whether the degree of learning influences the observation of memory retention and forgetting that follows a linear pattern. According to our retention accuracy from fragmented traces (RAFT) model, one factor that should increase the likelihood of this is when there is greater learning of the material. Higher levels of learning can increase the number of trace components, making it more likely that reconstruction or partial retrieval can lead to an accurate response on a memory test. Here, we report three new experiments, as well as re-analyses of existing data from the literature, to show that increasing the level of learning in some ways can lead to increases in the likelihood of observing linear forgetting. For Experiment 1, people learned materials to different levels. This learning involved cued recall testing during memorisation. Linear forgetting was observed with increased learning. For Experiment 2, learning did not involve cued recall testing. Linear forgetting was not observed. Although our aim was not to test theories of retrieval practice, for Experiment 3, we showed that when people engage in this process, the pattern of retention and forgetting becomes more linear. Overall, these data are consistent with the RAFT theory and support mechanisms that it suggests can lead to the observation of linear forgetting. [ABSTRACT FROM AUTHOR]

Purpose: This paper presents an educational virtual reality (VR) game and experiments with different methods of including it into the teaching process. The purpose of this research study is to discover if immersive VR games can be used as an effective pedagogical tool if blended with traditional lectures by assisting learning gain, memory and knowledge retention while increasing edutainment value. Design/methodology/approach: This research design comprises three different methods of learning: lecture-based involving lecture slides, infographics, and a video, game-based involving an immersive VR game of oil rig exploration, and the combination of lecture and game-based. Participants of each method filled up a questionnaire before and after participation to measure the learning gain, memory, and knowledge retention. Findings: From the predominant findings of the study, the combined method demonstrated a significant increase in learning gain, memory, and knowledge retention and maybe a potentially suitable pedagogical tool. Research limitations/implications: Limitations of the study include findings based on one VR game with a specific educational topic, additionally, it is suspected that having different participants for each of the three methods may have slightly affected the results, albeit to a limited extent. Practical implications: Findings of this study will provide evidence that VR games can be used alongside traditional lectures to aid in the learning process. Educators can choose to include VR games into their curriculums to improve the educational delivery process. Originality/value: This research contributes to ways of incorporating VR games into educational curriculums through findings of this study highlighting the combination of VR games with lectures. [ABSTRACT FROM AUTHOR]

Simple Summary: Learning and memory abilities and their roles in group decision-making have important ecological relevance in routine activities such as foraging and anti-predator behaviors in fish species. The aims of this study were to explore the spatial learning ability of juvenile cichlids (Chindongo demasoni), and the influence of heterogeneity of memory information among group members on group performance in a six-arm radiation maze. The spatial performance of individual fish improved and reached a stable level on the fifth day of training, and the memory of the space task is kept after 11 days of detraining. The spatial performance of heterogeneous groups composed of members with different memory information were found to change linearly with the increase of the proportion of trained members. This indicates that cichlids can obtain associative learning information through training, and it seems unlikely that cichlids' group behavior is determined by minority members in foraging context. Learning and memory abilities and their roles in group decision-making have important ecological relevance in routine activities such as foraging and anti-predator behaviors in fish species. The aims of the present study were to explore individual spatial learning abilities of juvenile cichlids (Chindongo demasoni) in a foraging context, and to explore the influence of heterogeneity of memory information among group members on group performance in a six-arm radiation maze. In the context of an association between landmarks and food, learning ability was evaluated by the speed and accuracy of reaching the arm with food during seven days of reinforcement, and memory retention was tested at intervals of 2, 5, 8 and 11 days of detraining. Then, the speed and accuracy of an eight-member group with different proportions of memory-trained fish were measured. Both speed and accuracy of individual fish improved significantly and linearly in the first five days of training and leveled off between five and seven days, with values 60% shorter (in speed) and 50% higher (in accuracy) compared to those of the first day. Neither speed nor accuracy showed any decrease after 11 days of detraining, suggesting memory retention of the spatial task. When measured in a group, the speed and accuracy of the majority of the group (more than half) in reaching the arm with food changed linearly with an increasing ratio of trained members. This shows that cichlids can acquire associative learning information through a training process, and group behavior of cichlids seems not likely be determined by a minority of group members under a foraging context. [ABSTRACT FROM AUTHOR]

The tourism activities linked to artificial provisioning of blacktip reef sharks (Carcharhinus melanopterus) and pink whiprays (Pateobatis fai) on a specific site in French Polynesia were suddenly and completely stopped due to a COVID‐19 lockdown that lasted 6 weeks from March 20 until April 30, 2020. Using both drone footage and underwater counting, we were able to track the abundance of those two species before, during, and after reopening and thus investigate the impact of provisioning on wild shark populations. The absence of any stimulus during this long period resulted in almost total desertion of the site by the elasmobranchs. However, 1 day prior to reopening, some individuals of both species positively reacted to the single acoustic stimulus of an engine boat, showing the resilience of conditioning, and some elasmobranchs reacted to acoustic and olfactive stimuli linked to the provisioning practice from the first day after reopening. During the first 2 weeks after reopening, the abundance of both species remained at reduced levels comparable to those observed between 2008 and 2010 for sharks; i.e., around 9 animals in the presence of local tourists. Pre‐lockdown abundance levels, reaching approximatively 15 individuals for sharks and 10 for rays, were considered restored 1 and 2 months after reopening for blacktip reef sharks and pink whiprays, respectively. These findings improve our capacity to better understand the potential effects of artificial provisioning tourism on the abundance of elasmobranchs by showing that conditioning is resilient for several weeks, suggesting that intermittent interruption of elasmobranchs feeding would not really help to decrease its impact on animal welfare. [ABSTRACT FROM AUTHOR]

Di-n-butyl phthalate (DBP) is commonly used as a plasticizer and its usage continues to increase in conjunction with plastic consumption. DBP is readily released into air, drinking water, and soil, and unfortunately, is a potent endocrine disrupter that impairs central nervous system functions. Previously DBP was found to (1) arrest the cell cycle of C17.2 neural progenitor cells (NPCs) at the G1 phase, (2) reduce numbers of newly generated neural stem cells in the mouse hippocampus, and (3) adversely affect learning and memory. Other investigators also noted DBP-mediated neurotoxic effects, but as yet, no study has addressed the adverse effects of DBP on neuronal differentiation. Data demonstrated that at 200 μM DBP induced apoptosis in rat embryo primary neurons by increasing reactive oxygen species levels and inducing mitochondrial dysfunction. However, no significant effect was detected on neurons at concentrations of ≤100 μM. In contrast, doublecortin/microtubule associated protein-2 (DCX/MAP2) immunocytochemistry showed that DBP at 100 μM delayed neuronal maturation by increasing protein levels of DCX (an immature neuronal marker), without markedly affecting cell viability. Further in vivo studies confirmed that DCX+ cell numbers were significantly elevated in the hippocampus of DBP-treated mice, indicating that DBP delayed neuronal maturation, which is known to be associated with impaired memory retention. Data demonstrated that DBP might disrupt neuronal maturation, which is correlated with reduced neurocognitive functions. [ABSTRACT FROM AUTHOR]

We propose a novel active learning framework for activity recognition using wearable sensors. Our work is unique in that it takes limitations of the oracle into account when selecting sensor data for annotation by the oracle. Our approach is inspired by human-beings’ limited capacity to respond to prompts on their mobile device. This capacity constraint is manifested not only in the number of queries that a person can respond to in a given time-frame but also in the time lag between the query issuance and the oracle response. We introduce the notion of mindful active learning and propose a computational framework, called EMMA, to maximize the active learning performance taking informativeness of sensor data, query budget, and human memory into account. We formulate this optimization problem, propose an approach to model memory retention, discuss the complexity of the problem, and propose a greedy heuristic to solve the optimization problem. Additionally, we design an approach to perform mindful active learning in batch where multiple sensor observations are selected simultaneously for querying the oracle. We demonstrate the effectiveness of our approach using three publicly available activity datasets and by simulating oracles with various memory strengths. We show that the activity recognition accuracy ranges from 21 to 97 percent depending on memory strength, query budget, and difficulty of the machine learning task. Our results also indicate that EMMA achieves an accuracy level that is, on average, 13.5 percent higher than the case when only informativeness of the sensor data is considered for active learning. Moreover, we show that the performance of our approach is at most 20 percent less than the experimental upper-bound and up to 80 percent higher than the experimental lower-bound. To evaluate the performance of EMMA for batch active learning, we design two instantiations of EMMA to perform active learning in batch mode. We show that these algorithms improve the algorithm training time at the cost of a reduced accuracy in performance. Another finding in our work is that integrating clustering into the process of selecting sensor observations for batch active learning improves the activity learning performance by 11.1 percent on average, mainly due to reducing the redundancy among the selected sensor observations. We observe that mindful active learning is most beneficial when the query budget is small and/or the oracle’s memory is weak. This observation emphasizes advantages of utilizing mindful active learning strategies in mobile health settings that involve interaction with older adults and other populations with cognitive impairments. [ABSTRACT FROM AUTHOR]

Mathematics is one of the fundamental subjects for engineering students. While learning mathematics, students often find it difficult or lose interest due to the complexity of the subject. Augmented reality (AR) could aid students to learn certain concepts or theories that were difficult to understand in the classroom and also has the capability to enhance the instructional/learning material. In this study, an AR‐based learning setting named geometry learning assistant (GLA) was developed to teach geometry to students in a mathematics course. GLA provides an interactive and immersive experience to the students that helped them to learn about 3D vectors and direction ratios. The application includes vector addition, cross product, position vector, direction ratios, and dot product with real‐time examples for better learning. Experimental research was organized to investigate the impact of AR intervention on learner's memory retention abilities and learning. Eighty 1st‐year polytechnic students participated in the study and they were divided randomly into two groups: experimental group (N = 40) and control group (N = 40). Students of the experimental group were made to learn using AR‐based GLA, whereas the students from the control group were treated using interactive simulation (IS). The experimental results showed that the learners from the experimental group have better memory retention abilities after 2 and 4 weeks of the learning activity. AR‐based GLA provided a 3D immersive learning experience to the students that enhanced their visualization of the core concepts, which additionally improved their memory retention abilities. [ABSTRACT FROM AUTHOR]

Summary: The self‐administered interview (SAI©) is a booklet in which eyewitnesses write down their memories of an incident without assistance. The SAI can gather a significant amount of eyewitness information, and completing the SAI soon after witnessing an event can improve later recall. This study aimed to reveal the factor of effectiveness of the SAI and specifically focused on the method of handwriting. Participants watched a video and immediately recalled the event in the three conditions: SAI‐writing, SAI‐speaking, and free recall (speaking). One week later, participants again recalled the event via free recall. The results showed that participants in the SAI‐writing condition reported more correct information than those in the other conditions at both time points. This suggests that a factor of effectiveness of the SAI is the method of writing. Thus, initial written recall using the SAI could facilitate later recall in police investigative interviews. [ABSTRACT FROM AUTHOR]

The brain can learn new tasks without forgetting old ones. This memory retention is closely associated with the long-term stability of synaptic strength. To understand the capacity of pyramidal neurons to preserve memory under different tasks, we established a plasticity model based on the postsynaptic membrane energy state, in which the change in synaptic strength depends on the difference between the energy state after stimulation and the resting energy state. If the post-stimulation energy state is higher than the resting energy state, then synaptic depression occurs. On the contrary, the synapse is strengthened. Our model unifies homo- and heterosynaptic plasticity and can reproduce synaptic plasticity observed in multiple experiments, such as spike-timing-dependent plasticity, and cooperative plasticity with few and common parameters. Based on the proposed plasticity model, we conducted a simulation study on how the activation patterns of dendritic branches by different tasks affect the synaptic connection strength of pyramidal neurons. We further investigate the formation mechanism by which different tasks activate different dendritic branches. Simulation results show that compare to the classic plasticity model, the plasticity model we proposed can achieve a better spatial separation of different branches activated by different tasks in pyramidal neurons, which deepens our insight into the memory retention mechanism of brains. [ABSTRACT FROM AUTHOR]

Evidence exists that a brief period of wakeful rest after learning can support the retention of memories, whereas a period filled with a cognitive task after learning can weaken the retention of memories. The present study in 10–13 year old children investigated whether wakeful resting after encoding is more beneficial for the retention of new verbal information than watching movies, which reflects a common everyday life/learning break activity in children at this age. Children encoded a word list. After immediate recall of this word list, they wakefully rested for 12 min. Next, children encoded another word list. After immediate recall of this word list, they watched animated short movies for 12 min. The order of the delay conditions (rest, movies) was counterbalanced across children. At the end of the experimental session, a surprise free recall test took place. Overall analyses revealed that while memory performance decreased over time in both the resting condition and movies condition, it decreased significantly more in the movies condition. These results indicate that wakeful resting supports the retention of verbal information in children aged 10–13 years. [ABSTRACT FROM AUTHOR]

Summary: Communication and information sharing via social media platforms is a common and popular activity. The majority of existing studies indicate that social media usage has detrimental effects on learning and memory. However, it is an open question as to whether social media usage affects memory even after learning. To test this, healthy young adults learned and immediately recalled a vocabulary list. Subsequent to recall, participants either wakefully rested for 8 min or used social media for 8 min. A delayed recall test took place after the wakeful resting condition and the social media condition and again after 1 day. Our results showed that social media usage, compared with wakeful resting, had detrimental effects on memory performance over both retention intervals. We assume that social media usage interfered with memory consolidation of learned vocabularies and suggest that learners opt for wakeful resting over social media usage as a learning‐break activity. [ABSTRACT FROM AUTHOR]

Memory is essential to enhance future survival and reproduction as it helps in storing and retrieving useful information to solve particular environmental problems. However, we lack quantitative evidence on how far animals in the wild can maintain given information for extended periods without reinforcement. Here, we document correlative evidence of cleaner fish Labroides dimidiatus remembering being caught in a barrier net for up to 11 months. In 2015, about 60% of cleaners from one large isolated reef had been used for laboratory experiments and then returned to their site of capture. Eleven months later, 50% of cleaners at the same site showed an unusual hiding response to the placement of the barrier net, in contrast to three control sites where no cleaners had been caught during the last 2 years. The results suggest that a single highly aversive event (i.e., being caught in a barrier net) resulted in cleaners storing long‐term crucial information that allowed them to avoid being caught again. Our results further our knowledge of fish cognitive capacities and long‐term memory retention. [ABSTRACT FROM AUTHOR]

The stress response facilitates survival through adaptation and is intimately related to cognitive processes. The Morris water maze task probes spatial learning and memory in rodents and glucocorticoids (i.e. corticosterone (CORT) in rats) have been suggested to elicit a facilitating action on memory formation. Moreover, the early aging period (around 16–18 months of age) is susceptible to stress- and glucocorticoid-mediated acceleration of cognitive decline. In this study, we tested three lines of rats selectively bred according to their individual differences in CORT responsiveness to repeated stress exposure during juvenility. We investigated whether endogenous differences in glucocorticoid responses influenced spatial learning, long-term memory, and reversal learning abilities in a Morris water maze task at early aging. Additionally, we assessed the quality of the different swimming strategies of the rats. Our results indicate that rats with differential CORT responsiveness exhibit similar spatial learning abilities but different long-term memory retention and reversal learning. Specifically, the high CORT responding line had a better long-term spatial memory, while the low CORT responding line was impaired for both long-term retention and reversal learning. Our modeling analysis of performance strategies revealed further important line-related differences. Therefore, our findings support the view that individuals with high CORT responsiveness would form stronger long-term memories to navigate in stressful environments. Conversely, individuals with low CORT responsiveness would be impaired at different phases of spatial learning and memory. Rats selected for different glucocorticoid responses to stress show differences in spatial learning and cognition. While the high responding animals have a better long-term spatial memory retention, the low responding rats have an inferior spatial memory and impaired reversal learning abilities. [ABSTRACT FROM AUTHOR]

Studies indicate that a brief period of wakeful rest after learning supports memory retention, whereas distraction weakens it. It is open for investigation whether advanced age has a significant effect on the impact of post-learning wakeful rest on memory retention for verbal information when compared to a cognitively demanding distraction task. In this study, we examined (1) whether post-learning rest promotes verbal memory retention in younger and older adults and (2) whether the magnitude of the rest benefit changes with increasing age. Younger adults and older adults learned and immediately recalled two consecutive word lists. After one word list, participants rested wakefully for 8 min; after the other list, they solved matrices. Memory performance was again tested in a surprise free recall test at the end of the experimental session. We found that, overall, younger adults outperformed older adults. Also, memory retention was higher following a wakeful rest phase compared to distraction. A detailed analysis revealed that this wakeful rest benefit was significant for the older adults group, whereas the younger adults group retained a similar amount of information in both post-encoding conditions. We assume that older adults can profit more from a wakeful rest phase after learning and are more prone to distraction than younger adults. With increasing age, a short break immediately after information uptake may help better retain the previously learned information, while distraction after learning tends to weaken memory retention. [ABSTRACT FROM AUTHOR]

Background: Selection acts on the phenotype, yet only the genotype is inherited. While both the phenotypic and genotypic response to short-term selection can be measured, the link between these is a major unsolved problem in evolutionary biology, in particular for complex behavioural phenotypes. Results: Here we characterize the genomic and the transcriptomic basis of associative learning ability in the parasitic wasp Nasonia vitripennis and use gene network analysis to link the two. We artificially selected for improved associative learning ability in four independent pairs of lines and identified signatures of selection across the genome. Allele frequency diverged consistently between the selected and control lines in 118 single nucleotide polymorphisms (SNPs), clustering in 51 distinct genomic regions containing 128 genes. The majority of SNPs were found in regulatory regions, suggesting a potential role for gene expression evolution. We therefore sequenced the transcriptomes of selected and control lines and identified 36 consistently differentially expressed transcripts with large changes in expression. None of the differentially expressed genes also showed sequence divergence as a result of selection. Instead, gene network analysis showed many of the genes with consistent allele frequency differences and all of the differentially expressed genes to cluster in a single co-expression network. At a functional level, both genomic and transcriptomic analyses implicated members of gene networks known to be involved in neural plasticity and cognitive processes. Conclusions: Taken together, our results reveal how specific cognitive abilities can readily respond to selection via a complex interplay between regulatory and sequence evolution. [ABSTRACT FROM AUTHOR]

Using the expression of the immediate early gene (IEG) egr-1 as a neuronal activity marker, brain regions potentially involved in learning and long-term memory functions in the grey bamboo shark were assessed with respect to selected visual discrimination abilities. Immunocytochemistry revealed a significant up-regulation of egr-1 expression levels in a small region of the telencephalon of all trained sharks (i.e., ‘early’ and ‘late learners’, ‘recallers’) when compared to three control groups (i.e., ‘controls’, ‘undisturbed swimmers’, ‘constant movers’). There was also a well-defined difference in egr-1 expression patterns between the three control groups. Additionally, some staining was observed in diencephalic and mesencephalic sections; however, staining here was weak and occurred only irregularly within and between groups. Therefore, it could have either resulted from unintentional cognitive or non-cognitive inducements (i.e., relating to the mental processes of perception, learning, memory, and judgment, as contrasted with emotional and volitional processes) rather than being a training effect. Present findings emphasize a relationship between the training conditions and the corresponding egr-1 expression levels found in the telencephalon of Chiloscyllium griseum. Results suggest important similarities in the neuronal plasticity and activity-dependent IEG expression of the elasmobranch brain with other vertebrate groups. The presence of the egr-1 gene seems to be evolutionarily conserved and may therefore be particularly useful for identifying functional neural responses within this group. [ABSTRACT FROM AUTHOR]

Purpose Field trips can change students’ attitudes and improve their learning performance, but they have rarely been investigated in logistics education research. The purpose of this paper is to present the findings from field trips that were designed to increase students’ knowledge of sustainable transport as well as to change their attitudes and behavioral intentions.Design/methodology/approach A total of 104 logistics students participated in this longitudinal panel study. Non-parametric statistical tests were used to test for significant effects.Findings Field trips build students’ knowledge, improve their attitudes and increase their behavioral intentions to use sustainable transport modes in the short and in the long term. Gains in knowledge exceed the results expected from traditional learning theories. Gender and school type are important moderating variables. Gender did not play an important role for knowledge gains, but for attitude and behavioral intentions.Research limitations/implications More research is needed to generalize the findings to other populations and longitudinal panel studies are necessary to investigate a long-term effect of field trips.Practical implications Field trips are an effective means for successful knowledge transfer and are suitable to trigger attitudinal and behavioral changes. The involvement of practitioners and the hands-on experience ensure that students combine theoretical with practical knowledge.Originality/value This is the first longitudinal panel study that investigates the effects of logistics field trips, which were developed collaboratively by industry, educational and research institutions. [ABSTRACT FROM AUTHOR]

The consumption of a specifically prepared silk fibroin protein enzymatic hydrolysate (FPEH) has been reported to improve cognitive function in healthy humans. The objective of the current study is to evaluate the dose-dependent effects of the FPEH on memory. Healthy adults with an average age of approximately 55 years were administered doses of 0,280,400 and 600 mg of FPEH per day in two divided doses for 3 weeks. The Rey-Kim Auditory Verbal Learning Test and the Rey-Kim Complex Figure Test of the Rey-Kim Memory Test were used to evaluate memory at baseline and after 3 weeks. The scores for each test were combined into the memory quotient score (MQ). Learning gradient, memory maintenance, retrieval efficacy, and drawing/recall scores were also compared. After 3 weeks of FPEH, dose-dependent increases were observed for the MQ, the learning gradient, the numbers of words remembered, the retrieval efficiency, and drawing/recall. The optimal dose for FPEH was 400 or 600 mg, depending on the end point measured. No adverse effects were reported. FPEH significantly improved measurements of memory in healthy adults by 3 weeks at doses over 280 mg daily, with an apparent plateau effect at 400-600 mg daily. [ABSTRACT FROM AUTHOR]

The idea that maintained LTP and memory are lost by either increase in intracellular Zn2+ in dentate granule cells or increase in intracellular Ca2+ was examined to clarify significance of the increases induced by excess synapse excitation. Both maintained LTP and space memory were impaired by injection of high K+ into the dentate gyrus, but rescued by co-injection of CaEDTA, which blocked high K+-induced increase in intracellular Zn2+ but not high K+-induced increase in intracellular Ca2+. High K+-induced disturbances of LTP and intracellular Zn2+ are rescued by co-injection of 6-cyano-7-nitroquinoxakine-2,3-dione, an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor antagonist, but not by co-injection of blockers of NMDA receptors, metabotropic glutamate receptors, and voltage-dependent calcium channels. Furthermore, AMPA impaired maintained LTP and the impairment was also rescued by co-injection of CaEDTA, which blocked increase in intracellular Zn2+, but not increase in intracellular Ca2+. NMDA and glucocorticoid, which induced Zn2+ release from the internal stores, did not impair maintained LTP. The present study indicates that increase in Zn2+ influx into dentate granule cells through AMPA receptors loses maintained LTP and memory. Regulation of Zn2+ influx into dentate granule cells is more critical for not only memory acquisition but also memory retention than that of Ca2+ influx. [ABSTRACT FROM AUTHOR]

Internet technology provides a new means of recalling and sharing personal memories in the digital age. What is the mnemonic consequence of posting personal memories online? Theories of transactive memory and autobiographical memory would make contrasting predictions. In the present study, college students completed a daily diary for a week, listing at the end of each day all the events that happened to them on that day. They also reported whether they posted any of the events online. Participants received a surprise memory test after the completion of the diary recording and then another test a week later. At both tests, events posted online were significantly more likely than those not posted online to be recalled. It appears that sharing memories online may provide unique opportunities for rehearsal and meaning-making that facilitate memory retention. [ABSTRACT FROM PUBLISHER]

Effectiveness of memory consolidation is determined by multiple factors, including sleep after learning, emotional valence, arousal and novelty. Few studies investigated how the effect of sleep compares with (and interacts with) these other factors, of which virtually none are in children. The present study did so by repeated assessment of declarative memory in 386 children (45% boys) aged 9-11 years through an online word-pair task. Children were randomly assigned to either a morning or evening learning session of 30 unrelated word-pairs with positive, neutral or negative valenced cues and neutral targets. After immediately assessing baseline recognition, delayed recognition was recorded either 12 or 24 h later, resulting in four different assessment schedules. One week later, the procedure was repeated with exactly the same word-pairs to evaluate whether effects differed for relearning versus original novel learning. Mixed-effect logistic regression models were used to evaluate how the probability of correct recognition was affected by sleep, valence, arousal, novelty and their interactions. Both immediate and delayed recognition were worse for pairs with negatively valenced or less arousing cue words. Relearning improved immediate and delayed word-pair recognition. In contrast to these effects, sleep did not affect recognition, nor did sleep moderate the effects of arousal, valence and novelty. The findings suggest a robust inclination of children to specifically forget the pairing of words to negatively valenced cue words. In agreement with a recent meta-analysis, children seem to depend less on sleep for the consolidation of information than has been reported for adults, irrespective of the emotional valence, arousal and novelty of word-pairs. [ABSTRACT FROM AUTHOR]

The effects induced by exogenous manipulation of endocannabinoid neurotransmission on emotion and memory are often contradictory. Among the different factors involved, of particular interest is the binding affinity of endocannabinoids, and their analogs, for other receptor families beyond cannabinoid receptors, such as the peroxisome proliferatoractivated receptors (PPARs), and the transient receptor potential cation channel subfamily V member 1 (TRPV1). The aim of this study was to investigate which receptor subtype mediates cannabinoid effects on memory consolidation for emotionally arousing experiences. We tested two cannabinoid compounds with different pharmacological properties in the inhibitory avoidance task, and evaluated whether the observed effects are mediated by cannabinoid, PPARa or TRPV1 receptor activation. We found that the synthetic cannabinoid agonist WIN55,212-2 and the FAAH inhibitor URB597 both enhanced memory consolidation for inhibitory avoidance training. WIN55,212-22 effects on memory consolidation were predominantly mediated by CB1 receptor activation but CB2 receptors were involved as well. The URB597-induced memory enhancement was dependent on the activation not only of CB1 and CB2 receptors but, notwithstanding, PPAR-a and TRPV1 receptors were involved as well. Our findings drive beyond the classical hypothesis centered on the unique role of CB1 receptor activation for cannabinoid effects on memory, and reveal new insights in the neural mechanisms of memory consolidation. [ABSTRACT FROM AUTHOR]

Prolonged metabolic suppression in the brain is a well-characterized secondary pathology of both experimental and clinical traumatic brain injury ( TBI). AMP-activated kinase ( AMPK) acts as a cellular energy sensor that, when activated, regulates various metabolic and catabolic pathways to decrease ATP consumption and increase ATP synthesis. As energy availability after TBI is suppressed, we questioned if increasing AMPK activity after TBI would improve cognitive outcome. TBI was delivered using the electromagnetic controlled cortical impact model on male Sprague-Dawley rats (275-300 g) and C57 BL/6 mice (20-25 g). AMPK activity within the injured parietal cortex and ipsilateral hippocampus was inferred by western blots using phospho-specific antibodies. The consequences of acute manipulation of AMPK signaling on cognitive function were assessed using the Morris water maze task. We found that AMPK activity is decreased as a result of injury, as indicated by reduced AMPK phosphorylation and corresponding changes in the phosphorylation of its downstream targets: ribosomal protein S6 and Akt Substrate of 160 kDa ( AS160). Increasing AMPK activity after injury using the drugs 5-amino-1-β- d-ribofuranosyl-imidazole-4-carboxamide or metformin did not affect spatial learning, but significantly improved spatial memory. Taken together, our results suggest that decreased AMPK activity after TBI may contribute to the cellular energy crisis in the injured brain, and that AMPK activators may have therapeutic utility. [ABSTRACT FROM AUTHOR]

Objectives: Amyloid-beta (Aβ) peptide deposition into insoluble plaques is a pathological hallmark of Alzheimer's disease (AD), but soluble oligomeric Aβ is considered to be more potent and has been hypothesized to directly impair learning and memory. Also, evidences from some clinical studies indicated that Aβ oligomer formation is the major cause for early AD onset. However, the biochemical mechanism involved in the oligomer-induced toxicity is not very well addressed. So, thise present study was undertaken to study the effects of single intracerebroventricular (icv) injection of protofibrillar Aβ 1-42 on the behavioral and biochemical profile in rats. Methods: Rats were divided into two groups (n = 8 per group): (1) sham control group and (2) Aβ 1-42 injected group. A single dose of protofibrillar Aβ 1-42 (5 ul) through icv injection was bilaterally administered into the dorsal hippocampus, while sham control animals were administered with 5 µl of vehicle. Results: The results demonstrated that the protofibrillar Aβ significantly inhibited long-term memory retention and increased anxiety levels as shown by the behavioral studies. The amyloid deposits were present inside the brain even six weeks after injection as confirmed by thioflavin-T staining and the neurodegeneration induced by these deposits was confirmed by Nissl's staining in hippocampal and cortical regions. The amyloid aggregates induced reactive oxygen species (ROS) production, acetylcholinesterase activity, nitrite levels, lipid peroxidation, and inhibited antioxidant enzyme activity in hippocampus, cortex, and striatum regions of rat brain after six weeks. Discussion: The present study indicated that protofibrillar Aβ 1-42 injection altered long term memory, induced anxiety-like behavior and also developed Alzheimer's disease like pathology in rats. [ABSTRACT FROM AUTHOR]

Context:Morus nigraL. (Moraceae) has various uses in traditional medicine. However, the effect ofM. nigraon cognitive impairment has not been investigated yet. Objective: The objective of this study is to determine the phenolic acid content and DNA damage protection potential ofM. nigraleaf extract and to investigate the extract effect on cognitive impairment and oxidative stress in aging mice. Materials and methods: Phenolic acid content was determined by quantitative chromatographic analysis. DNA damage protection potential was evaluated on pBR322 plasmid DNA. Thirty-two Balb-C mice were randomly divided into four groups (control,d-galactose,d-galactose + M. nigra50, andd-galactose + M. nigra100). Mice were administeredd-galactose (100 mg/kg, subcutaneous) andM. nigra(50 or 100 mg/kg, orally) daily for 8 weeks. Behavioral responses were evaluated with Morris water maze. Activities of antioxidant enzymes and levels of malondialdehyde (MDA) were assayed in serum, brain, and liver. Results: In extract, vanillic (632.093 μg/g) and chlorogenic acids (555.0 μg/g) were determined. The extract between 0.02 and 0.05 mg/mL effectively protected all DNA bands against the hazardous effect of UV and H2O2.Morus nigrasignificantly improved learning dysfunctions (p < 0.01), increased memory retention (p < 0.01), reduced MDA levels (p < 0.05), and elevated SOD, GPx, and CAT activities (p < 0.05) compared with thed-galactose group. Discussion and conclusion: These results show thatM. nigrahas the potential in improving cognitive deficits in mice and thatM. nigramay be useful to suppress aging, partially due to its scavenging activity of free radicals and high antioxidant capacity. [ABSTRACT FROM AUTHOR]

Methylglyoxal (MG) is formed during normal metabolism by processes like glycolysis, lipid peroxidation, and threonine catabolism, and its accumulation is associated with various degenerative diseases, such as diabetes and arterial atherogenesis. Furthermore, MG has also been reported to have toxic effects on hippocampal neurons. However, these effects have not been studied in the context of neurogenesis. Here, we report that MG adversely affects hippocampal neurogenesis and induces neural progenitor cell (NPC) death. MG significantly reduced C17.2 NPC proliferation, and high concentration of MG (500 μM) induced cell death and elevated oxidative stress. Further, MG was found to activate the ERK signaling pathway, indicating elevated stress response. To determine the effects of MG in vivo, mice were administrated with vehicle or MG (0.5 or 1 % in drinking water) for 4 weeks. The numbers of BrdU-positive cells in hippocampi were significantly lower in MG-treated mice, indicating impaired neurogenesis, but MG did not induce neuronal damage or glial activations. Interestingly, MG reduced memory retention when administered to mice at 1 % but not at 0.5 %. In addition, the levels of hippocampal BDNF and synaptophysin were significantly lower in the hippocampi of mice treated with MG at 1 %. Collectively, our findings suggest MG could be harmful to NPCs and to hippocampal neurogenesis. [ABSTRACT FROM AUTHOR]

This study is to further assess the effect of cessation of chronic cigarette smoke exposure(CSE) on memory, learning and asymptomatic level of performance(ALOP). The design of the study was a single blind randomized control trial involving exposed and control group of rats. Water-maze assessment of learning, memory and ALOP revealed a progressive decline in the latency-time with each sessions, for all study groups- implying that learning was taking place. The female exposed rats had the most difficulty in learning the task compared to the other study groups. In-addition, ALOP was averagely attained by the 4th and 5th session for the exposed and control groups. Furthermore, memory for these sessions was demonstrated by all study groups, with the female-exposed group depicting the highest level. Hippocampal histology revealed a dichotomy between exposed and control groups. The exposed groups had nuclei condensation-pyknosis and edematous changes. Hence, the observation of both a difficulty in learning and a high level of memorization in the female-exposed group suggest that, this study setting favors the recovery of the apparatuses-especially hippocampus, involved in these function from any deleterious effect of chronic CSE. And that the recovery of the males is faster than those of the females. [ABSTRACT FROM AUTHOR]

Spontaneous movement tempo (SMT) was a popular field of study of the Gestalt psychologists It can be determined from subjects freely tapping out a rhythm with their finger, and it has been found to average about 2 Hz. A previous study showed that SMT changed after the observation of rhythmical movements performed at frequency different from the SMT. This effect was long-lasting only when movement execution immediately followed action observation (AO). We recently demonstrated that only when AO was combined with peripheral nerve stimulation (AO-PNS) was it possible to induce plastic changes in the excitability of the motor cortex, whereas AO and PNS alone did not evoke any changes. Here we investigated whether the observation of rhythmical actions at a frequency higher than the SMT combined with PNS induced lasting changes in SMT even in absence of immediate movement execution. Forty-eight participants were assigned to four groups. In AO-PNS group they observed a video showing a right hand performing a finger opposition movement sequence at 3 Hz and contemporarily received an electrical stimulation at the median nerve; in AO group and PNS group participants either observed the same video or received the same electrical stimulation of the AO-PNS group, respectively; in LANDSCAPE group subjects observed a neutral video. Participants performed a finger opposition movement sequence at spontaneous movement rate before and 30 min after the conditioning protocols. Results showed that SMT significantly changed only after AO-PNS. This result suggested that the AO-PNS protocol was able to induce lasting changes in SMT due to neuroplasticity mechanisms, indicating possible application of AO-PNS in rehabilitative treatments. [ABSTRACT FROM AUTHOR]

Spontaneous movement tempo (SMT) was a popular field of study of the Gestalt psychologists It can be determined from subjects freely tapping out a rhythm with their finger, and it has been found to average about 2 Hz. A previous study showed that SMT changed after the observation of rhythmical movements performed at frequency different from the SMT. This effect was long-lasting only when movement execution immediately followed action observation (AO). We recently demonstrated that only when AO was combined with peripheral nerve stimulation (AO-PNS) was it possible to induce plastic changes in the excitability of the motor cortex, whereas AO and PNS alone did not evoke any changes. Here we investigated whether the observation of rhythmical actions at a frequency higher than the SMT combined with PNS induced lasting changes in SMT even in absence of immediate movement execution. Forty-eight participants were assigned to four groups. In AO-PNS group they observed a video showing a right hand performing a finger opposition movement sequence at 3 Hz and contemporarily received an electrical stimulation at the median nerve; in AO group and PNS group participants either observed the same video or received the same electrical stimulation of the AO-PNS group, respectively; in LANDSCAPE group subjects observed a neutral video. Participants performed a finger opposition movement sequence at spontaneous movement rate before and 30 min after the conditioning protocols. Results showed that SMT significantly changed only after AO-PNS. This result suggested that the AO-PNS protocol was able to induce lasting changes in SMT due to neuroplasticity mechanisms, indicating possible application of AO-PNS in rehabilitative treatments. [ABSTRACT FROM AUTHOR]

ABSTRACT There is no evidence on the precise role of synaptic Zn2+ signaling on the retention and recall of recognition memory. On the basis of the findings that intracellular Zn2+ signaling in the dentate gyrus is required for object recognition, short-term memory, the present study deals with the effect of spatiotemporally blocking Zn2+ signaling in the dentate gyrus after LTP induction and learning. Three-day-maintained LTP was impaired 1 day after injection of clioquinol into the dentate gyrus, which transiently reduced intracellular Zn2+ signaling in the dentate gyrus. The irreversible impairment was rescued not only by co-injection of ZnCl2, which ameliorated the loss of Zn2+ signaling, but also by pre-injection of Jasplakinolide, a stabilizer of F-actin, prior to clioquinol injection. Simultaneously, 3-day-old space recognition memory was impaired 1 day after injection of clioquinol into the dentate gyrus, but not by pre-injection of Jasplakinolide. Jasplakinolide also rescued both impairments of 3-day-maintained LTP and 3-day-old memory after injection of ZnAF-2DA into the dentate gyrus, which blocked intracellular Zn2+ signaling in the dentate gyrus. The present paper indicates that the blockade and/or loss of intracellular Zn2+ signaling in the dentate gyrus coincidently impair maintained LTP and recognition memory. The mechanism maintaining LTP via intracellular Zn2+ signaling in dentate granule cells, which may be involved in the formation of F-actin, may retain space recognition memory. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objective(s): The cholinergic system plays an important role in learning and memory. This study investigated the effects of curcumin (turmeric extract) and the cholinergic system and their interaction on memory retention of passive avoidance learning in adult male Wistar rats. Materials and Methods: At first, an injection cannula was implanted in right ventricles of the animals. One week after the surgery, the animals were trained with a shuttle box set up. Post-training, injections were performed in all experiments. Administration of curcumin increased memory retention. Also administrations of nicotine and pilocarpine, the cholinergic receptor agonists, increased memory retention, while it is decreased by succinylcholine and scopolamine, the cholinergic receptor antagonists. Then co-administration of curcumin and cholinergic drugs were performed. Intraperitoneal and intracerebroventricular injections were applied for the curcumin and cholinergic drugs, respectively. Results: Co-administration of curcumin (45 mg/kg) with a low dose of nicotine (0.1 μg/rat) or pilocarpine (0.5 μg/rat) increased memory retention significantly. Effects of succinylcholine (0.01, 0.1 and 0.5 μg/rat) or scopolamine (0.1, 1 and 5 μg/rat) were attenuated by curcumin markedly (45 mg/kg). Conclusion: The results suggest that curcumin has a close interaction with cholinergic system in memory retention process. [ABSTRACT FROM AUTHOR]