阻断内侧前额叶皮质TrkB受体对大鼠认知和海马BDNF表达的影响

脑源性神经营养因子(brain-derived neurotrophic factor, BDNF)广泛参与了个体学习和记忆等认知功能, 通过与其酪氨酸激酶受体(tyrosine kinase, TrkB)特异性结合, 实现其多种神经生化功能。本研究观察了TrkB受体阻断剂ANA-12的慢性内侧前额叶皮质(medial prefrontal cortex, mPFC)注射对大鼠旷场行为、Morris水迷宫空间学习和逆反学习的影响。研究结果表明, mPFC的慢性BDNF阻断显著降低了大鼠在逆反学习测试中的逃离潜伏期和运动距离即增强了大鼠的逆反学习能力, 但不影响其旷场行为和水迷宫空间学习能力。同时, 慢性阻断mPFC-TrkB受体也并未导致大鼠海马BDNF蛋白含量的显著改变。这些结果提示, 对于大鼠的Morris水迷宫空间学习和逆反学习, mPFC-BDNF主要在逆反学习调节中发挥重要作用。这对于进一步探索海马和mPFC在调节个体认知功能中各自的作用及其潜在的相互关系提供了有力的证据和支持。     

慢性应激损害大鼠学习记忆且抑制海马及额叶FGF2蛋白表达

慢性应激能够影响学习和记忆等认知功能。海马和额叶是与学习和记忆联系密切的脑区, 参与信息的获得、保持及提取。碱性成纤维生长因子(FGF2)对神经元发生、存活以及损伤修复具有重要促进作用, 目前成为神经系统退行性疾病相关研究的热点。本研究旨在探索慢性应激如何影响大鼠学习和记忆能力, 以及这一过程中FGF2蛋白在海马和额叶中表达的改变。实验中将16只雄性SD大鼠随机分为对照组和慢性应激组, 采用慢性不可预见温和刺激建立大鼠慢性应激模型, 通过Morris水迷宫实验及Y迷宫实验检测学习与记忆功能的改变, 并对海马及额叶中FGF2蛋白的表达情况进行Western blot及免疫组织化学检测。结果发现, 5周慢性应激导致大鼠学习和记忆能力受损, 海马及额叶FGF2蛋白表达下调。因此认为, FGF2蛋白可能参与慢性应激损害学习记忆能力的机制, 提示FGF2可能是诊断和治疗神经系统退行性病变的分子靶目标。     

Executive Function: The Search for an Integrated Account

ABSTRACT— In general, executive function can be thought of as the set of abilities required to effortfully guide behavior toward a goal, especially in nonroutine situations. Psychologists are interested in expanding the understanding of executive function because it is thought to be a key process in intelligent behavior, it is compromised in a variety of psychiatric and neurological disorders, it varies across the life span, and it affects performance in complicated environments, such as the cockpits of advanced aircraft. This article provides a brief introduction to the concept of executive function and discusses how it is assessed and the conditions under which it is compromised. A short overview of the diverse theoretical viewpoints regarding its psychological and biological underpinnings is also provided. The article concludes with a consideration of how a multilevel approach may provide a more integrated account of executive function than has been previously available.     

前额皮层肾上腺素能受体在工作记忆中的作用

前额皮层去甲肾上腺素能神经支配主要来自脑干蓝斑核。前额皮层存在不同类型的肾上腺素能受体。其中突触后α2及β2肾上腺素能受体的激活提高工作记忆;α1及β1肾上腺素能受体的激活损害工作记忆。不同受体是通过激活不同的信号通路发挥对工作记忆的调节作用。来自人类被试的研究结果与对动物的研究结果之间尚存在不一致。了解前额皮层不同肾上腺素受体的作用为开发治疗与前额皮层功能失调相关疾病的药物提供了新的方向。     

ENSEMBLE RECORDINGS IN AWAKE RATS: ACHIEVING BEHAVIORAL REGULARITY DURING MULTIMODAL STIMULUS PROCESSING AND DISCRIMINATIVE LEARNING

To meet an increasing need to examine the neurophysiological underpinnings of behavior in rats, we developed a behavioral system for studying sensory processing, attention and discrimination learning in rats while recording firing patterns of neurons in one or more brain areas of interest. Because neuronal activity is sensitive to variations in behavior which may confound the identification of neural correlates, a specific aim of the study was to allow rats to sample sensory stimuli under conditions of strong behavioral regularity. Our behavioral system allows multimodal stimulus presentation and is coupled to modules for delivering reinforcement, simultaneous monitoring of behavior and recording of ensembles of well isolated single neurons. Using training protocols for simple and compound discrimination, we validated the behavioral system with a group of 4 rats. Within these tasks, a majority of medial prefrontal neurons showed significant firing‐rate changes correlated to one or more trial events that could not be explained from significant variation in head position. Thus, ensemble recordings can be combined with discriminative learning tasks under conditions of strong behavioral regularity.     

Brain mechanisms associated with background monitoring of the environment for potentially significant sensory events

Background monitoring is a necessary prerequisite to detect unexpected changes in the environment, while being involved in a primary task. Here, we used fMRI to investigate the neural mechanisms that underlie adaptive goal-directed behavior in a cued task switching paradigm during real response conflict or, more generally, when expectations on the repetitive features of the environment were violated. Unexpected changes in sensory stimulus attributes in the currently unattended stimulus dimension thereby led to activations in a bilateral network comprising inferior lateral frontal, intraparietal, and posterior medial frontal brain regions, independent of whether these attributes elicited a factual response conflict or not. This fronto-parietal network may thus play an important role in adaptive responding to potentially significant events outside the current focus of attention.     

早期高级认知发展与前额叶功能发育的fNIRS研究

儿童早期阶段是各项认知能力和脑发育的关键阶段。近红外光谱成像技术(fNIRS)凭借其非侵害性、便捷操作以及对头动容忍度高等特点,在早期阶段儿童认知发展与脑发育的研究中得到越来越多的应用。从早期高级认知发展与前额叶功能的单侧优势变化、对应前额叶脑区逐渐专门化、发展关键期与前额叶功能的可塑性,以及前额叶功能异常与早期发展障碍的关系等四个方面对基于fNIRS技术开展的早期认知发展与脑发育的研究进展进行了梳理和分析。指出未来研究应探究儿童早期认知能力发展和脑发育的轨迹及关键期,探讨有发展性障碍家族风险儿童的早期大脑发育特点,为早期教育和发展障碍的早期预警提供依据。     

消费者购买决定与前额叶脑活动的不对称性——来自EEG的证据

摘要：目前营销科学界对消费者购买决策阶段的神经运作机制仍然缺乏准确的理解,本研究探索了大脑前额叶不对称性是否与消费者购买决策有关。采用田野实验方法,21名受试者在真实的在线购物中,分别对自己购物车里5件物品做出真实的购买决策,他们的EEG脑电图被完整记录了下来,共观察到104次购买决策过程。结果表明,在产品页面观看过程中,受试者的gamma频带前额叶不对称,与随后真实购买行为显著相关。alpha、beta频带额叶不对称与购买决策无关。结果还发现与商品的售价对beta和gamma不对称指数的调节效应,且调节效果正好相反。本研究发现了消费者在购买决策过程中一种独特的EEG成分——前额叶gamma波不对称指数（PAIγ）与肯定的购买意愿和实际购买行为相关性最强。     

海马结构、前额皮层或尾-壳核损毁对大鼠空间认知能力的影响

本研究的目的是探讨海马结构(HF)、前额皮层(PFC)和尾-壳核(CP)在大鼠空间认知加工中的作用。实验观察到HP或PFC损毁大鼠Morris迷宫学习或记忆作业成绩显著低于CP损毁组和控制组(CG);HF损毁大鼠主要采用与其它各组不同的“非图类”搜索策略。搜索策略的差异提示:HF和PFC在大鼠图认知加工系统中处于不同的功能层次,HF起相对重要的作用。CP几乎不影响大鼠空间认知能力,表现出哺乳类与鸟类同源结构的功能分化倾向。