Does medial prefrontal cortex activity during self‐knowledge reference reflect the uniqueness of self‐knowledge?1

Abstract: For this study, functional magnetic resonance imaging was used to examine whether medial prefrontal cortex (MPFC) activity during self‐knowledge reference reflects the uniqueness of self‐knowledge. Experiment 1 investigated neural activity during self‐knowledge reference (“Does the word describe you?”) and self‐monitoring (“Does the word make you feel pleasant?”). The results showed that self‐knowledge reference and self‐monitoring activate common neural substrates within the MPFC. Experiment 2 compared neural activity produced by self‐knowledge reference, other‐knowledge (acquaintance‐knowledge) reference (“Does this word describe the person?”), and evaluation (“Is this word socially desirable?”). Results showed no increase in MPFC activity during self‐knowledge reference relative to other‐knowledge reference. Furthermore, self‐knowledge reference and other‐knowledge reference share common neural substrates within the MPFC. The results described indicate that it is unlikely that MPFC activity during self‐knowledge reference reflects the uniqueness of self‐knowledge. The feature, as reflected in MPFC activity, is discussed.     

Hierarchically organized behavior and its neural foundations: a reinforcement learning perspective

Research on human and animal behavior has long emphasized its hierarchical structure—the divisibility of ongoing behavior into discrete tasks, which are comprised of subtask sequences, which in turn are built of simple actions. The hierarchical structure of behavior has also been of enduring interest within neuroscience, where it has been widely considered to reflect prefrontal cortical functions. In this paper, we reexamine behavioral hierarchy and its neural substrates from the point of view of recent developments in computational reinforcement learning. Specifically, we consider a set of approaches known collectively as hierarchical reinforcement learning, which extend the reinforcement learning paradigm by allowing the learning agent to aggregate actions into reusable subroutines or skills. A close look at the components of hierarchical reinforcement learning suggests how they might map onto neural structures, in particular regions within the dorsolateral and orbital prefrontal cortex. It also suggests specific ways in which hierarchical reinforcement learning might provide a complement to existing psychological models of hierarchically structured behavior. A particularly important question that hierarchical reinforcement learning brings to the fore is that of how learning identifies new action routines that are likely to provide useful building blocks in solving a wide range of future problems. Here and at many other points, hierarchical reinforcement learning offers an appealing framework for investigating the computational and neural underpinnings of hierarchically structured behavior.     

Object-location memory: A lesion-behavior mapping study in stroke patients

Object-location memory is an important form of spatial memory, comprising different subcomponents that each process specific types of information within memory, i.e. remembering objects, remembering positions and binding these features in memory. In the current study we investigated the neural correlates of binding categorical (relative) or coordinate (exact) position information with objects in memory. Therefore, an object-location memory battery was used, including different task conditions assessing object-location memory, i.e. memory for position information per se, and binding object information with coordinate and categorical position information. Sixty-one stroke patients with focal brain lesions were examined and compared with 77 healthy matched controls. The lesion subtraction method was used to define the area of overlap. Results indicate an important role of the left posterior parietal cortex in the binding of both categorical and coordinate positions with object information. Additionally, the hippocampus seems important for categorical object-location memory. This suggests that categorical and coordinate object-location memory depend on similar cognitive and neural systems.     

Enhanced divergent thinking and creativity in musicians: a behavioral and near-infrared spectroscopy study

Empirical studies of creativity have focused on the importance of divergent thinking, which supports generating novel solutions to loosely defined problems. The present study examined creativity and frontal cortical activity in an externally-validated group of creative individuals (trained musicians) and demographically matched control participants, using behavioral tasks and near-infrared spectroscopy (NIRS). Experiment 1 examined convergent and divergent thinking with respect to intelligence and personality. Experiment 2 investigated frontal oxygenated and deoxygenated hemoglobin concentration changes during divergent thinking with NIRS. Results of Experiment 1 indicated enhanced creativity in musicians who also showed increased verbal ability and schizotypal personality but their enhanced divergent thinking remained robust after co-varying out these two factors. In Experiment 2, NIRS showed greater bilateral frontal activity in musicians during divergent thinking compared with nonmusicians. Overall, these results suggest that creative individuals are characterized by enhanced divergent thinking, which is supported by increased frontal cortical activity.     

前运动皮质与数字加工:脑功能成像研究的元分析研究

许多应用PET与fMRI技术的脑功能成像研究发现,数字加工任务会显著引起前运动皮质的激活。习惯上认为,这一结果可能与任务执行过程中的动作反应,如手指按键、默读或眼动等有关。近年来的研究则表明,这一区域不仅具有动作功能,同时也具有其它非动作的认知功能。在本研究中,对17篇关于数字加工的脑功能成像研究进行了元分析,以考察前运动皮质在数字加工中的作用。研究结果发现,运动前区的背外侧(PMd)与腹外侧(PMv)在大多数数字加工任务中有显著激活,而运动辅助区(SMA)的激活则相对较少。数字比较、加法与减法任务在PMd区域有更多的激活,而乘法任务则在PMv区域有更多激活。数字自身特征对PMd、PMv与SMA喙部区域的激活有显著的调节作用。这一结果表明,前运动皮质在数字加工过程中可能扮演着比动作反应更为重要的角色。     

执行功能与攻击行为关系的研究

攻击行为产生的原因十分复杂,受当今认知神经科学的影响,心理学研究人员从执行功能的角度来探讨攻击行为。现有的研究主要从心理学、流行病学、行为神经学、神经心理学和神经成像角度,考察和分析二者内在的关联,结果表明在暴力犯罪、反社会人格、杀人犯、精神病患者、少年犯、注意缺陷-多动障碍等群体,执行功能与攻击行为间存在很强的负向关联。将来的研究需要拓宽研究被试群体,深入考察内在的脑机制,制定恰当的攻击行为干预方法。     

Mirror Neurons and the Evolution of Embodied Language

ABSTRACT— Mirror neurons are a class of neurons first discovered in the monkey premotor cortex that activate both when the monkey executes an action and when it observes the same action made by another individual. These neurons enable individuals to understand actions performed by others. Two subcategories of mirror neurons in monkeys activate when they listen to action sounds and when they observe communicative gestures made by others, respectively. The properties of mirror neurons could constitute a substrate from which more sophisticated forms of communication evolved; this would make sense, given the anatomical and functional homology between part of the monkey premotor cortex and Broca's area (the "speech" area of the brain) in humans. We hypothesize that several components of human language, including some aspects of phonology and syntax, could be embedded in the organizational properties of the motor system and that a deeper knowledge of this system could shed light on how language evolved.     

前额叶皮质损伤患者的情绪异常

人类前额叶皮质与情绪之间有着密切的关系,文章在相关的临床和神经成像研究结果基础上,分析了前额叶皮质损伤对情绪行为造成的影响,分别概述了精神分裂症、重性抑郁和焦虑患者的情绪变化、前额叶切除对情绪的影响以及左右前额叶皮质与情绪的关系,重点阐述了前额叶功能异常的神经生理学特点,认为情绪的改变会随着前额叶皮质不同部位的结构缺损或功能变化而有所不同,此有利于对前额叶皮质损伤患者情绪异常的评价与防治。     

情绪大脑机制研究的进展

文章综述情绪大脑机制研究的最新进展。情绪的脑机制——大脑回路,包括前额皮层、杏仁核、海马、前部扣带回、腹侧纹状体等。前额皮层中的不对称性与趋近和退缩系统有关,左前额皮层与趋近系统和积极感情有关,右前额皮层与消极感情和退缩有关。杏仁核易被消极的感情刺激所激活,尤其是恐惧。海马在情绪的背景调节中起着重要作用。前额皮层和杏仁核激活不对称性的个体差异是情绪个体差异的生理基础。情绪的中枢回路有可塑性。