青少年网络成瘾研究进展

青少年网络成瘾是信息时代的一种阻碍青少年健康成长的问题。本文对青少年网络成瘾的测量、影响因素及其干预等问题进行综述,并对未来研究方向提出建议,为以后研究提供借鉴。     

Structural properties of personal meaning systems: A new approach to measuring meaning of life

This article introduces a new qualitative–quantitative approach to assess meaning of life. The participants described their sources of meaning and how they were interconnected. Four quantitative measures for (1) the accessibility of meaning-related knowledge, the degree of (2) differentiation and (3) elaboration of personal meaning systems, and (4) their coherence were calculated. The sample consisted of 59 theology and science students. The study tested (a) whether the structural properties of personal meaning systems predicted health and well-being, and (b) reflected different degrees of expertise in constructing meaning. Differentiation, elaboration, and coherence measures correlated with health and well-being and predicted life satisfaction. Theology students presented more differentiated, elaborated, and coherent personal meaning systems than science students. Both results indicate that assessing structural properties of personal meaning systems can be a promising new approach to measure meaning of life.     

Orienting numbers in mental space: Horizontal organization trumps vertical

While research on the spatial representation of number has provided substantial evidence for a horizontally oriented mental number line, recent studies suggest vertical organization as well. Directly comparing the relative strength of horizontal and vertical organization, however, we found no evidence of spontaneous vertical orientation (upward or downward), and horizontal trumped vertical when pitted against each other (Experiment 1). Only when numbers were conceptualized as magnitudes (as opposed to nonmagnitude ordinal sequences) did reliable vertical organization emerge, with upward orientation preferred (Experiment 2). Altogether, these findings suggest that horizontal representations predominate, and that vertical representations, when elicited, may be relatively inflexible. Implications for spatial organization beyond number, and its ontogenetic basis, are discussed.     

EPS Mid-Career Award 2014

In visual search, observers try to find known target objects among distractors in visual scenes where the location of the targets is uncertain. This review article discusses the attentional processes that are active during search and their neural basis. Four successive phases of visual search are described. During the initial preparatory phase, a representation of the current search goal is activated. Once visual input has arrived, information about the presence of target-matching features is accumulated in parallel across the visual field (guidance). This information is then used to allocate spatial attention to particular objects (selection), before representations of selected objects are activated in visual working memory (recognition). These four phases of attentional control in visual search are characterized both at the cognitive level and at the neural implementation level. It will become clear that search is a continuous process that unfolds in real time. Selective attention in visual search is described as the gradual emergence of spatially specific and temporally sustained biases for representations of task-relevant visual objects in cortical maps.     

The relationship between executive functions,episodic feeling-of-knowing and confidence judgements

Metamemory processes and executive control may be related, given that both are frontally mediated. However, previous behavioural research has been limited in identifying common processes driving this somewhat weak relationship partly because they mostly relied upon global executive measures and composite scores of executive function (EF). The present study investigated the relationship between specific EFs (task shifting, interference resolution), working memory capacity and feeling-of-knowing (FOK) and confidence judgements (CONF) in an episodic memory task. We found that, of the EFs, only task-switching performance was correlated with FOK accuracy and proposed a shared mechanism that may be at play in both task-switching and FOK judgements. We also demonstrated that interference resolution and episodic memory measures were related, suggesting strategic influences on memory retrieval. Finally, we found a strong consistency in the strength and accuracy of FOK and CONF judgements, possibly due to retrieval-based mechanisms in both types of judgements.     

On Categorical Equivalences of Commutative BCK-algebras

A commutative BCK-algebra with the relative cancellation property is a commutative BCK-algebra (X;*,0) which satisfies the condition: if a ≤ x, a ≤ y and x * a = y * a, then x = y. Such BCK-algebras form a variety, and the category of these BCK-algebras is categorically equivalent to the category of Abelian ℓ-groups whose objects are pairs (G, G ₀), where G is an Abelian ℓ-group, G ₀ is a subset of the positive cone generating G ⁺ such that if u, v ∈ G ₀, then 0 ∨ (u - v) ∈ G ₀, and morphisms are ℓ-group homomorphisms h: (G, G ₀) → (G′,G′₀) with f(G ₀) ⫅ G′₀. Our methods in particular cases give known categorical equivalences of Cornish for conical BCK-algebras and of Mundici for bounded commutative BCK-algebras (= MV-algebras). This revised version was published online in June 2006 with corrections to the Cover Date.     

构建21世纪美国公共卫生体系的原则

美国卫生与福利部长沙拉拉博士在一次演讲中提出了构建２１世纪美国公共卫生体系的十大原则,这些原则包括公共卫生与信息革命;大力发展预防医学;医学研究;消除卫生保健的悬殊状况;新世纪卫生人卫生人培养;保护大学生卫生中心以及医学伦理学等主要内容。这些原则对我们思考规划２１世纪的医疗卫生体系及医学教育系不无借鉴启迪意义。     

Timing of human cortical functions during cognition: role of MEG

Understanding of sensory and cognitive brain processes requires information about activation timing within and between different brain sites. Such data can be obtained by magnetoencephalography (MEG) that tracks cortical activation sequences with a millisecond temporal accuracy. MEG is gaining a well-established role in human neuroscience, complementing with its excellent temporal resolution the spatially more focused brain imaging methods. As examples of MEG's role in cognitive neuroscience, we discuss time windows related to cortical processing of sensory and multisensory stimuli, effects of the subject's own voice on the activity of their auditory cortex, timing of brain activation in reading, and cortical dynamics of the human mirror-neuron system activated when the subject views another person's movements.     

Coordination tending towards an anti-phase relationship determines greater sway reduction during entrainment with a simulated partner

The increased risk of falls in the older aged population demands the development of assistive robotic devices capable of effective balance support. For the development and increased user acceptance of such devices, which provide balance support in a human-like way, it is important to understand the simultaneous occurrence of entrainment and sway reduction in human-human interaction. However, sway reduction has not been observed yet during a human touching an external, continuously moving reference, which rather increased human body sway. Therefore, we investigated in 15 healthy young adults (27.20±3.55 years, 6 females) how different simulated sway-responsive interaction partners with different coupling modes affect sway entrainment, sway reduction and relative interpersonal coordination, as well as how these human behaviours differ depending on the individual body schema accuracy. For this, participants were lightly touching a haptic device that either played back an average pre-recorded sway trajectory (“Playback”) or moved based on the sway trajectory simulated by a single-inverted pendulum model with either a positive (Attractor) or negative (Repulsor) coupling to participant's body sway. We found that body sway reduced not only during the Repulsor-interaction, but also during the Playback-interaction. These interactions also showed a relative interpersonal coordination tending more towards an anti-phase relationship, especially the Repulsor. Moreover, the Repulsor led to the strongest sway entrainment. Finally, a better body schema contributed to a reduced body sway in both the “reliable” Repulsor and the “less reliable” Attractor mode. Consequently, a relative interpersonal coordination tending more towards an anti-phase relationship and an accurate body schema are important to facilitate sway reduction.     

Brain dynamics of visual anticipation during spatial occlusion tasks in expert tennis players

Stimulus identification and action outcome understanding for a rapid and accurate response selection, play a fundamental role in racquet sports. Here, we investigated the neurodynamics of visual anticipation in tennis manipulating the postural and kinematic information associated with the body of opponents by means of a spatial occlusion protocol. Event Related Potentials (ERPs) were evaluated in two groups of professional tennis players (N = 37) with different levels of expertise, while they observed pictures of opponents and predicted the landing position as fast and accurately as possible. The observed action was manipulated by deleting different body districts of the opponent (legs, ball, racket and arm, trunk). Full body image (no occlusion) was used as control condition. The worst accuracy and the slowest response time were observed in the occlusion of trunk and ball. The former was associated with a reduced amplitude of the ERP components likely linked to body processing (the N1 in the right hemisphere) and visual-motor integration awareness (the pP1), as well as with an increase of the late frontal negativity (the pN2), possibly reflecting an effort by the insula to recover and/or complete the most correct sensory-motor representation. In both occlusions, a decrease in the pP2 may reflect an impairment of decisional processes upon action execution following sensory evidence accumulation. Enhanced amplitude of the P3 and the pN2 components were found in more experienced players, suggesting a greater allocation of resources in the process connecting sensory encoding and response execution, and sensory-motor representation.