Neural correlates of Traditional Chinese Medicine induced advantageous risk-taking decision making

This fMRI study examined the neural correlates of the observed improvement in advantageous risk-taking behavior, as measured by the number of adjusted pumps in the Balloon Analogue Risk Task (BART), following a 60-day course of a Traditional Chinese Medicine (TCM) recipe, specifically designed to regulate impulsiveness in order to modulate risk-taking behavior. The 14 participants recruited for this study were randomly assigned to the experimental and control groups and the TCM recipe (Panax, 520 mg; Astragalus membranaceous Bunge, 520 mg; Masnetitum, 840 mg; Ostrea gigas Thumb, 470 mg; Thinleaf Milkwort Root Radix Polygalae, 450 mg; and Os Draconis, 470 mg) was administered, as a diet supplement, to the seven participants in the experimental group. The neural activity of the two groups was monitored by a 3T MRI scanner, before and after the 60-day treatment. Associated with the improved advantageous risk-taking behavior seen in the experimental group, significantly stronger blood oxygenation level dependent (BOLD) responses were observed in the bilateral dorsolateral prefrontal cortex (DLPFC), left putamen, left thalamus, right insula, and right anterior cingulate cortex (ACC), regions which have previously been reported as being involved in risk-taking decision making. The effect of the TCM in improving advantageous risk-taking decision making appears to have been related to the enhanced efficiency of the cognitive affective system, the PFC–ACC–insula–striatum network, which functions to inhibit impulsiveness, to sensitize reward-related information, and to allow the opportunity, during risk estimation, to evaluate potential gains and losses. The findings of this study suggest that interventions acting on factors modulating risk-taking decision making could have a beneficial effect in terms of optimizing risk-taking behavior.     

Brain correlates of aesthetic expertise: a parametric fMRI study

Several studies have demonstrated that acquired expertise influences aesthetic judgments. In this paradigm we used functional magnetic resonance imaging (fMRI) to study aesthetic judgments of visually presented architectural stimuli and control-stimuli (faces) for a group of architects and a group of non-architects. This design allowed us to test whether level of expertise modulates neural activity in brain areas associated with either perceptual processing, memory, or reward processing. We show that experts and non-experts recruit bilateral medial orbitofrontal cortex (OFC) and subcallosal cingulate gyrus differentially during aesthetic judgment, even in the absence of behavioural aesthetic rating differences between experts and non-experts. By contrast, activity in nucleus accumbens (NAcc) exhibits a differential response profile compared to OFC and subcallosal cingulate gyrus, suggesting a dissociable role between these regions in the reward processing of expertise. Finally, categorical responses (irrespective of aesthetic ratings) resulted in expertise effects in memory-related areas such as hippocampus and precuneus. These results highlight the fact that expertise not only modulates cognitive processing, but also modulates the response in reward related brain areas.     

An empirical and computational investigation of perceiving and remembering event temporal relations

Events have beginnings, ends, and often overlap in time. A major question is how perceivers come to parse a stream of multimodal information into meaningful units and how different event boundaries may vary event processing. This work investigates the roles of these three types of event boundaries in constructing event temporal relations. Predictions were made based on how people would err according to the beginning state, end state, and overlap heuristic hypotheses. Participants viewed animated events that include all the logical possibilities of event temporal relations, and then made temporal relation judgments. The results showed that people make use of the overlap between events and take into account the ends and beginnings, but they weight ends more than beginnings. Neural network simulations showed a self-organized distinction when learning temporal relations between events with overlap versus those without.     

时序信息和空间信息在工作记忆中的分离存储

采用相对新近性判断范式（judgments of relative recency）,通过三个实验探讨了工作记忆中时序信息和空间信息的存储方式及其关系。实验一比较了有无空间线索两种条件下时序信息的记忆绩效,结果发现,有无空间线索并不影响对时序信．E-的记忆。实验二和实验三通过控制刺激呈现的视野范围和减少呈现位置的不确定性来利化空间线索,结果表明,时序信息的记忆绩效也不受空间线索的影响。由此推论,工作记忆中的时序信息和空间信息是分离编码存储的,加入空间线索并不能提高时序信息的记忆绩效。     

Effects of rodent prefrontal lesions on object-based, visual scene memory

It has been suggested that certain prefrontal areas contribute to a neural circuit that mediates visual object memory. Using a successive go/no-go visual scene discrimination task, object-based long-term memory was assessed in two rodent prefrontal regions. Rewarded trials consisted of a standard scene of four toy objects placed over baited food wells. The objects and their locations composing the standard scene remained constant for the duration of the study. Trials in which one of the standard scene objects was replaced with a novel object were not rewarded. Following the establishment of a significant difference between latency to approach the rewarded standard scene compared to latency to approach non-rewarded scenes, quinolinic acid or control vehicle was infused into either the prelimbic and infralimbic cortices or the anterior cingulate cortex. Following a 1 week recovery period, subjects were retested. Animals with prelimbic/infralimbic cortex lesions displayed a profound and sustained deficit, whereas, animals with anterior cingulate cortex lesions showed a slight initial impairment but eventually recovered. Both lesion groups acquired a simple single object discrimination task as quickly as controls indicating that the deficits on the original scene discrimination task were not due to motivational, response inhibition, or perceptual problems.     

A model of episodic memory: Mental time travel along encoded trajectories using grid cells

The definition of episodic memory includes the concept of mental time travel: the ability to re-experience a previously experienced trajectory through continuous dimensions of space and time, and to recall specific events or stimuli along this trajectory. Lesions of the hippocampus and entorhinal cortex impair human episodic memory function and impair rat performance in tasks that could be solved by retrieval of trajectories. Recent physiological data suggests a novel model for encoding and retrieval of trajectories, and for associating specific stimuli with specific positions along the trajectory. During encoding in the model, external input drives the activity of head direction cells. Entorhinal grid cells integrate the head direction input to update an internal representation of location, and drive hippocampal place cells. Trajectories are encoded by Hebbian modification of excitatory synaptic connections between hippocampal place cells and head direction cells driven by external action. Associations are also formed between hippocampal cells and sensory stimuli. During retrieval, a sensory input cue activates hippocampal cells that drive head direction activity via previously modified synapses. Persistent spiking of head direction cells maintains the direction and speed of the action, updating the activity of entorhinal grid cells that thereby further update place cell activity. Additional cells, termed arc length cells, provide coding of trajectory segments based on the one-dimensional arc length from the context of prior actions or states, overcoming ambiguity where the overlap of trajectory segments causes multiple head directions to be associated with one place. These mechanisms allow retrieval of complex, self-crossing trajectories as continuous curves through space and time.     

Environmental enrichment improves behavioral performance and auditory spatial representation of primary auditory cortical neurons in rat

Environmental enrichment (EE) has an important role in brain plasticity. Early research has shown that EE increases the response strength of neurons in the auditory cortex, but it remains unknown whether EE can influence the process of spatial localization in the auditory system. In this study, we raised rats in enriched and standard conditions from postnatal day 10 to day 56. By testing behavioral tasks via auditory cues, we have shown that EE improved the number of correct scores, but decreased the reaction time and azimuth deviation in behavioral performance of sound-azimuth discrimination. By in vivo extracellular recording, we have shown that EE enhanced the directional sensitivity of neurons in the primary auditory cortex. For example, EE rats had a smaller spatial receptive field, sharper frequency tuning curve and directional selective curve of auditory neurons compared with normal rats. Our findings indicate that early exposure to EE increases directional sensitivity. These results provide an insight into developmental plasticity in the auditory system.     

中文阅读中的边界效应及其消除：事件持续效应

运用动窗技术探讨中文阅读中的边界效应及其消除的条件,包括3个实验。实验一探讨中文阅读中是否存在边界效应,结果发现,边界效应同样存在于中文阅读中;实验二、三探讨时间切分标记能否消除边界效应以及消除的条件,结果发现,只有当切分标记表示的时间在前一事件持续的时间跨度外时才能消除边界效应,如果切分标记表示的时间仍在前一事件持续的时间跨度内,则不能消除边界效应,本研究称此为事件持续效应。从本研究结果中可以得出,时间切分标记降低了主题转换句子所需要的认知加工能量     

预搜索过滤分心物的机制

如果先呈现若干分心物,然后添加靶子与其他分心物,那么就会改善搜索——预搜索效应。对于过滤分心物的潜在机制,研究者相继提出了主动抑制说、突然呈现说与时间分离说等理论。这些理论都有其合理的一面,能解释一些特定的实验现象,但任何单一机制都无法解释所有的实验现象。文章提出,未来的研究应该整合已有的实验现象与理论,系统考察旧客体与新客体的作用,重点整合抑制说与突现说,它们可能是一个连续体的两端     

普高生与中职生的个人未来目标和担忧

以1995名普高生和中职生为被试,采用未来取向问卷(中文版),考察了普高生和中职生的个人未来目标和担忧的内容与时间广度。研究发现:普高生与中职生较多地关注未来教育、职业、婚姻/家庭、家庭安康和自我,预期重要生活事件发生在二三十岁左右。普高生更多地提及教育目标和担忧以及与家庭安康有关的担忧,而中职生更多地提及职业目标和担忧,并预期职业目标和担忧发生的年龄较早;农村学生更多地提及与未来教育和家庭安康有关的目标,而相对较少提及职业目标,并预期教育和职业目标以及职业担忧发生的年龄早于城市学生;男生更多地提及职业和婚姻/家庭目标以及与自我有关的担忧,而女生更多地提及与家庭安康有关的目标和教育担忧,并预期教育和职业目标发生的年龄较早。