Memory Maintenance

ABSTRACT— Change in the synaptic communication between neurons—known as synaptic plasticity—plays a key role in learning and memory. It is not yet clear, however, whether the properties of synaptic plasticity are sufficient to account for long-term-memory maintenance. Recent studies have revealed that synaptic plasticity can indeed persist for weeks or months, as might be expected of a long-term-memory mechanism. However, memories encoded by neural systems are not static; they continue to evolve as new learning occurs. Furthermore, neural-network modeling has shown that synapses must be able to reconfigure their connection strengths during new learning if old information is to be preserved. Recent tests confirm that synapses, once modified, retain their capacity for further modification, indicating that they can indeed operate in the manner predicted to be necessary for memory maintenance in a dynamic learning network.     

网络医疗的发展和思考

随着科学技术、网络技术迅猛的发展,许多互联网业务如网上求医、网上购药、网上保健也日渐火热,成为人们防治疾病的又一手段。网络医疗是网络科技与医疗技术结合的产物,在信息高速发展的今天,它已成为医学交流中一道亮丽的风景线,各国都在不遗余力发展自己的远程医疗系统,这无疑将推动医学模式的进步。然而作为一种新的医疗手段,网络医疗目前仍存在着诸多的弊端和问题,这些问题反过来又可制约网络医疗的发展,因此必须在技术、政策、法律各方面予以完善,使之更好地服务于人类。     

人工神经网络模型在心理学研究中的运用

人工神经网络是对真实神经元网络的粗略模拟,具有容错性、抗干扰性、高效性等特征,具有学习、记忆等强大的认知功能,因此适宜于心理学许多领域的模拟研究。借助神经网络模型不仅可以模拟和验证以往的实验室研究;还能深入探讨感知、联想、学习和记忆等认知过程的具体发生机理,把握其内在机制;它对探讨内隐记忆、内隐学习等无意识认知过程有极大的启发作用。     

Are unsupervised neural networks ignorant? Sizing the effect of environmental distributions on unsupervised learning

Learning environmental biases is a rational behavior: by using prior odds, Bayesian networks rapidly became a benchmark in machine learning. Moreover, a growing body of evidence now suggests that humans are using base rate information. Unsupervised connectionist networks are used in computer science for machine learning and in psychology to model human cognition, but it is unclear whether they are sensitive to prior odds. In this paper, we show that hard competitive learners are unable to use environmental biases while recurrent associative memories use frequency of exemplars and categories independently. Hence, it is concluded that recurrent associative memories are more useful than hard competitive networks to model human cognition and have a higher potential in machine learning.     

审美的神经机制研究及其美学意义

本文主要介绍了审美神经机制研究的初步成果,特别有关Zeki,Solso等人开创性的研究工作,并着重讨论了这些研究工作的美学意义,指出审美神经机制的研究不但在美学理论的确证方面,具有更强的说服力和广泛的应用性,而且在21世纪美学理论的重建方面,也一定会起着不可替代的重要作用。     

Creativity Research Overlooks the Study of Resilience among Young Children: A Bibliometric Network Review

Creativity researchers are increasingly interested in understanding when, how, and for whom creativity can be beneficial. Previous reviews have demonstrated that creativity research largely ignores the study of its impact on factors that promote health, and well-being among populations of adults. It is unclear, in fact, whether this gap in research also extends to creativity research among young children. This paper addresses this issue. Early childhood is a crucial stage for the cognitive development of young children who remain highly sensitive to stress, and adversity. It is therefore essential to identify and promote factors that are beneficial to early childhood resilience, thereby contributing to documenting more of the effects of creative activities on positive outcomes. This paper presents a review with a bibliometric analysis of 1000 randomly selected articles from the Web of Science, without bias towards any specific peer-reviewed journal. The analysis of 454 included articles shows that approximately 80% of the included studies focus on creativity as an outcome (replicating previous findings with a larger sample), with only 3.78% investigating creative activities as predictors among young children. In this small percentage, most of the studies addressed creative activities in young children related to resilience outcomes.     

Global VOR gain adaptation during near fixation to foveal targets

Long-term rotational vestibulo-ocular (VOR) adaptation occurs during systematic dysmetria between visual and vestibular afferents, adjusting eye-rotation angular velocity to re-establish retinal stability of the visual field. Due to translational motion of the eyes during head rotation, VOR gain is higher when fixating near objects. The current study measures VOR in humans before and after 6 min of exposure to a foveal near-target during sinusoidal whole-body rotation at 0.45 Hz. All of six participants showed post-exposure increases in open-loop VOR gain after fixating near targets, demonstrating a mean modulation increase of open-loop VOR gain from 0.86 before adaptation to 1.2 after adaptation. We discuss a number of theoretical and applied implications.     

神经管缺陷的病因、预防与产前控制

神经管缺陷(NTDS)是一种常见的先天性中枢神经系统畸形,其发生率占据我国出生缺陷的前列。本文从其发病原因、产前诊断及预防措施进行系统分析,希望能找出一条降低其发生率的有效途径,从而进一步提高我国的人口素质。     

Autoshaping and automaintenance: a neural-network approach

This article presents an interpretation of autoshaping, and positive and negative automaintenance, based on a neural-network model. The model makes no distinction between operant and respondent learning mechanisms, and takes into account knowledge of hippocampal and dopaminergic systems. Four simulations were run, each one using an A-B-A design and four instances of feedfoward architectures. In A, networks received a positive contingency between inputs that simulated a conditioned stimulus (CS) and an input that simulated an unconditioned stimulus (US). Responding was simulated as an output activation that was neither elicited by nor required for the US. B was an omission-training procedure. Response directedness was defined as sensory feedback from responding, simulated as a dependence of other inputs on responding. In Simulation 1, the phenomena were simulated with a fully connected architecture and maximally intense response feedback. The other simulations used a partially connected architecture without competition between CS and response feedback. In Simulation 2, a maximally intense feedback resulted in substantial autoshaping and automaintenance. In Simulation 3, eliminating response feedback interfered substantially with autoshaping and automaintenance. In Simulation 4, intermediate autoshaping and automaintenance resulted from an intermediate response feedback. Implications for the operant-respondent distinction and the behavior-neuroscience relation are discussed.     

主观幸福感的脑机制

主观幸福感是社会认知领域一直关注的重要问题。Kahneman等人提出的评价系统模型为主观幸福感的研究提供了基本框架。主观幸福感形成过程中,评价系统的主要产物包括即时效用、回忆效用、抉择效用和预期效用,这些效用都有着各自特殊的神经机制。主观幸福感的影响因素分为内部和外部因素,它们也对应着各异的神经基础。未来主观幸福感领域的研究应遵循生理机制和心理机制相结合的整合研究思路。