内侧颞叶与来源记忆

来源记忆不同于项目记忆。早期的研究认为来源记忆的神经基础主要是前额叶,但近几年的相关研究发现内侧颞叶在来源记忆中的作用也是相当重要的,健康被试的功能神经成像研究和内侧颞叶损伤病人研究都为内侧颞叶在来源记忆中的作用提供了可靠证据。     

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。     

条件反射性免疫抑制激活过程中下丘脑核团c-fos的表达

利用经典条件反射性免疫抑制的动物模型,以糖精水为条件刺激（CS）,免疫抑制剂-环磷酰胺为非条件刺激 （UCS）,观测两次CS-UCS结合训练后,再次条件刺激诱发条件反射性免疫抑制作用的动态改变,获得条件反射性免疫抑制和味觉厌恶性条件反射各自保持的情况,并在此基础上,采用c-fos免疫组化技术, 进一步观察再次条件刺激诱发条件反射性免疫抑制反应时大鼠下丘脑各核团内FOS蛋白的表达情况。结果表明,条件反射性免疫抑制作用在训练后第5天较强,第30天基本消失,而味觉厌恶性条件反射始终稳定保持到第30天。进一步研究显示出,下丘脑室旁核FOS蛋白表达在第5天非常密集,而第30天几乎没有表达,与细胞免疫功能改变在时程和趋势上具有一致性。通过FOS蛋白表达时程差异比较,提示下丘脑室旁核可能是CNS内介导CS诱导的免疫抑制效应的重要核团。     

谈机体的非特异性功能损伤

为了探讨能够改变临床治疗过程中的过分强调疾病面轻视机体功能调节的现象,提出了非特异性功能损伤的概念。这一概念的普遍性存在于常见病、多发病中,其共性体现在以下兵脑为中心的神经内分泌免疫网络的功能中,它的个性可能正是中医药治疗疾病的客观依据之一。     

阻碍条件性恐惧记忆消退的原因分析

创伤后应激障碍是个体经历严重应激后形成的一种焦虑障碍,对其治疗的关键是消退由创伤应激导致的条件性恐惧记忆,但目前最有效的暴露疗法并不能真正有效地抑制患者恐惧记忆的表达.对条件性恐惧的动物模型研究发现情绪性增强效应、恐惧记忆二级条件化与再巩固、内侧前额叶皮层功能不足等均能够阻碍条件性恐惧记忆的消退.针对这几个方面可以探索治疗创伤后应激障碍的相应方法.     

Predatory aggression: Midbrain-pontine junction rather than hypothalamus as the critical structure?

Electrical stimulation of sites in the region of the ventromedial periaqueductal gray substance at the level of the midbrain–pontine junction was found to elicit a predatory attack by a cat upon a rat. The intensity of stimulation required to elicit the attack was three to four times less than that required to elicit similar behavior by hypothalamic stimulation. The results suggest that anatomically distinct regions of the periaqueductal gray substance are concerned with the regulation of predatory and affective forms of aggressive behavior. The difficulty in reconciling these results with the preeminent role assigned the hypothalamus in the organization of predatory behavior is also discussed.     

边界促进空间导航的认知神经机制

边界是指在人的视野中占据较大比例,且具有立体拓展平面的障碍物,对于人类和动物的空间导航行为具有极大的促进作用。认知发展研究发现儿童早期(1岁半～2岁)通过加工边界的空间几何结构实现物体定位,并且随着年龄的发展逐渐学会利用边界的高度信息(3.1岁～4.7岁)、长度信息(4～5岁)、视觉阻碍性信息(5岁)等完成空间导航。基于这些认知过程,神经影像学研究主要以成人为研究被试,发现大脑中的内侧颞叶和顶叶脑区在边界加工中有着不同功能作用。具体而言,边界的空间几何结构及构成要素(高度、长度和角度)体位置的学习和提取则由海马负责。但是,仍存在一些研究问题值得未来深入S探c讨i。e第n一c,e拓展深化边界促进与后顶叶之间的功能交互。第三,密切关注大脑对场地边界与场地中心编码的心理或神经表征的区别和联系。第四,重点考察阿尔兹海默症有关基因易感人群在基于边界导航的行为受损情况。最后,延伸探讨边界在长时记忆、时间知觉、视觉空间、社交网络等领域的影响机制。     

The very same thing: Extending the object token concept to incorporate causal constraints on individual identity

The contributions of feature recognition, object categorization, and recollection of episodic memories to the re-identification of a perceived object as the very same thing encountered in a previous perceptual episode are well understood in terms of both cognitive-behavioral phenomenology and neurofunctional implementation. Human beings do not, however, rely solely on features and context to re-identify individuals; in the presence of featural change and similarly-featured distractors, people routinely employ causal constraints to establish object identities. Based on available cognitive and neurofunctional data, the standard object-token based model of individual re-identification is extended to incorporate the construction of unobserved and hence fictive causal histories (FCHs) of observed objects by the pre-motor action planning system. It is suggested that functional deficits in the construction of FCHs are associated with clinical outcomes in both autism spectrum disorders and later-stage stage Alzheimer's disease.     

Orbital and ventromedial prefrontal cortex functioning in Parkinson's disease: neuropsychological evidence

A recent paper (Zald & Andreotti, 2010) reviewed neuropsychological tasks that assess the function of the orbital and ventromedial portions of the prefrontal cortex (OMPFC). Neuropathological studies have shown that the function of the OMPFC should be preserved in the early stages of Parkinson's disease (PD) but becomes affected in the advanced stages of PD. This pattern has also been suggested by studies that have shown that dopaminergic drugs impair the performance of early PD patients in OMPFC tasks that involve reinforcement learning but enhance the performance of advanced PD patients. Based on these empirical findings, we reviewed the neuropsychological evidence of OMPFC functions in PD patients to test two hypotheses regarding the following: (1) OMPFC functions at different stages of PD; (2) different effects of dopaminergic drugs on OMPFC functions based on PD stage and task demand. We focused our review only on the neuropsychological tasks that were specific and sensitive to the functions of the OMPFC and that were adopted at different stages of PD, such as reversal learning tasks, the Iowa Gambling Task and the affective Theory of Mind task. We found robust empirical evidence that in early PD, OMPFC functions are preserved and dopaminergic drugs result in a detrimental effect when the task involves reinforcement learning. Further studies are needed to verify the status of OMPFC functions in non-demented, advanced PD and to describe the longitudinal course of OMPFC functions in this clinical population.     

下丘脑异常与抑郁症

近年来的研究发现了抑郁模型动物或抑郁症病人下丘脑异常的大量证据, 诸如下丘脑体积及神经元数目的改变, 下丘脑-垂体-内分泌轴的改变, 下丘脑相关激素、受体及其基因、神经肽的改变, 下丘脑与其他脑区功能联系的改变等等。然而, 下丘脑与抑郁症关系的研究所获证据多来自动物实验、或临床间接指标(如病人外周血激素水平等), 或病人脑组织尸检, 缺乏来自病人活体下丘脑异常的直接证据。今后的研究可考虑运用影像学的手段更直接地探索抑郁症患者活体下丘脑的结构特征和功能特征, 以期发现抑郁症的生物学标记及其可靠性指标, 为抑郁症的客观诊断提供依据, 为揭示抑郁症病理机制提供线索。