Emotional reactivity following surgery to the prefrontal cortex

We aimed to elicit emotion in patients with surgically circumscribed lesions of the prefrontal cortex (PFC) in order to elucidate the precise functional roles in emotion processing of the discrete subregions comprising the ventromedial PFC, including the medial PFC and orbitofrontal cortex (OFC). Three components of emotional reactivity were measured: subjective experience, behaviour, and physiological response. These included measures of self‐reported emotion, observer‐rated facial expression of emotion and measurements of heart rate and heart rate variability (HRV) during film viewing, and a measure of subjective emotional change since surgery. Patients with lesions to the ventromedial PFC demonstrated significant differences compared with controls in HRV during the film clips, suggesting a shift to greater dominance of sympathetic input. In contrast, patients with lesions restricted to the OFC showed significant differences in HRV suggesting reduced sympathetic input. They also showed less facial expression of emotion during positive film clips, and reported more subjective emotional change since surgery compared with controls. This human lesion study is important for refining theoretical models of emotion processing by the ventromedial PFC, which until now have primarily been based on anatomical connectivity, animal lesion, and human functional neuroimaging research. Such theories have implications for the treatment of a wide variety of emotional disorders.     

The role of the human extrastriate visual cortex in mirror symmetry discrimination: a TMS-adaptation study

The human visual system is able to efficiently extract symmetry information from the visual environment. Prior neuroimaging evidence has revealed symmetry-preferring neuronal representations in the dorsolateral extrastriate visual cortex; the objective of the present study was to investigate the necessity of these representations in symmetry discrimination. This was accomplished by the use of state-dependent transcranial magnetic stimulation, which combines the fine resolution of adaptation paradigms with the assessment of causality. Subjects were presented with adapters and targets consisting of dot configurations that could be symmetric along either the vertical or horizontal axis (or they could be non-symmetric), and they were asked to perform a symmetry discrimination task on the targets while fixating the center of the screen. TMS was applied during the delay between the adapter and the test stimulus over one of four different sites: Left or Right V1/V2, or left or right dorsolateral extrastriate cortex (DLO). TMS over both Left and Right DLO reduced the adaptation effect in detecting vertical and horizontal symmetry, although the Left DLO effect on horizontal symmetry and the Right DLO effect on both vertical and horizontal symmetry were present only when considering subjects who showed a behavioral adaptation effect in the baseline No-TMS condition. Application of TMS over the Left or Right V1/V2 did not modulate the adaptation effect. Overall, these data suggest that both the Left and Right DLO contain neuronal representations tuned to mirror symmetry which play a causal role in symmetry discrimination.     

Conflict and Cognitive Control in the Brain

ABSTRACT— Recent research from cognitive psychology and cognitive neuroscience has suggested that the control mechanisms by which people are able to regulate task performance can be dissociated into evaluative and executive components. One process, implemented in the anterior cingulate cortex of the brain, monitors the amount of conflict that occurs during information processing; another process, implemented in the dorsolateral prefrontal cortex, is involved with maintaining the requirements of the task at hand and with biasing information processing in favor of appropriate responses. In the current article, we review this theory and some of the research that has supported it, including its implication for understanding cognitive disturbances in clinical disorders such as schizophrenia and obsessive-compulsive disorder. We conclude by addressing several interesting possibilities for future research.     

Can Constructive Thinking Predict Decision Making?

We assume that executive function constitutes an integrated set of cognitive processes that mediate working memory, planning, inhibition, flexibility, and decision making. Despite the acknowledged theoretical connection between executive function processes and emotional intelligence, such relationships have rarely been investigated. The purpose of this study was to examine the potential relationship between constructive thinking, conceived as a component of emotional intelligence, and executive function, as indexed by various existing neuropsychological and experimental instruments. We used the Constructive Thinking Inventory as a measure of emotional intelligence. We found that some constructive thinking subscales were able to predict distinct executive function variables. Emotional Coping, Categorical Thinking, and Esoteric Thinking subscales explained performance on various measures of executive function. Thus, we conclude that intervention programs designed to train a specific component of emotional intelligence, namely constructive thinking, could also facilitate performance in executive function processes, and vice versa. Copyright © 2011 John Wiley & Sons, Ltd.     

Neural correlates of stimulus response and stimulus outcome shifting in healthy participants and MS patients

Introduction

Adaptation to changing situations can be mediated by two strategies: (1) Evaluation of a response and (2) Evaluation of outcome values in relation to objects. Previous studies indicate that response shifting is associated with a network comprising the left frontal cortex and parietal cortex connected by the superior longitudinal fascicle, whereas outcome evaluation is associated with a network consisting of the orbitofrontal cortex, amygdala and uncinate fascicle. However, these studies rarely compared both kinds of adaptation directly and existing fMRI studies with healthy subjects are not informative about the role of the two fiber systems.

Methods

We analyzed stimulus response shifting and stimulus outcome shifting in two studies, one fMRI-study on healthy participants and one study on patients with MS involving structural MRI (Diffusion Tensor Imaging, Voxel Based Morphometry, Ventricular volumetry). Two tasks were used, identical in presentation but different in instruction, controlling for effects of lower level processing. In the SRS task, participants had to perform a “Go” or “NoGo” response depending on a stimulus change: if the stimulus remained the same, they had to continue with the former type of response, if it changed they had to adapt their response pattern. In the SOS task they had to perform a “Go” response only if the presented stimulus corresponded to that of an internal alternating series.

Results

fMRI findings showed that SRS is related to a bilateral parietal-premotor network. In the left hemisphere the prefrontal cortex was also involved. SOS was lateralized to the right hemisphere, particularly to the anterior temporal pole and amygdala, and the inferior parietal cortex. MS patients impaired on this task suffered from lesions in the right uncinate fascicle and showed an enlarged right frontal lateral ventricle.

Conclusion

With physically identical tasks, a functional neuronal segregation can be demonstrated for stimulus response shifting (bilateral activations with a focus in the left prefrontal cortex) and stimulus outcome shifting (right anterior temporal lobe and right supramarginal gyrus).     

Relationships between executive function,working memory,and decision-making on the Iowa Gambling Task: Evidence from ventromedial patients,dorsolateral patients,and normal subjects

The results of previous studies are inconsistent in regard to the relationship between the Iowa Gambling Task (IGT), working-memory (WM), and executive tasks, and whether these cognitive processes could be considered as mechanisms underlying a decision-making deficit. Moreover, the relationship between the IGT and executive measures is examined based on a limited number of executive tasks, within different populations showing diffuse damage. In addition, there are fewer studies carried out within control participants, with those studies also being inconclusive. It is also suggested that the association of the IGT performance with executive tasks depends on whether the IGT was running under ambiguity or under risk. In this work, all of these issues are studied. Results showed that both patients with ventromedial (VMPFC, N = 10) and dorsolateral (DLPFC, N = 10) prefrontal cortex lesions are significantly impaired on almost all executive tasks, WM tasks, and the IGT. Furthermore, when the IGT is run under risk, there are significant correlations between executive measures and the IGT for the DLPFC patients and the control participants (N = 34) but not the VMPFC patients. No correlation was found between WM tasks and the IGT for both frontal subgroups and control participants. These findings suggested that the mechanisms underlying the IGT deficit differ according to the lesion locations.     

数字加工的脑功能成像研究进展及其皮层定位

数字加工是人类最重要的认知功能之一。当前的脑功能成像研究有助于对数字加工与皮层之间的联系进行更精确的定位。基于对上世纪80年代来有关数字加工脑功能成像研究的主要成果的回顾,尤其是一些重要区域,如双侧顶叶与前额叶等在数字加工中的地位与作用,以及不同脑区之间的关系进行了探讨,并对一个广泛运用的数字加工神经机制模型进行了简要评述。在此基础上,对数字加工的皮层定位问题进行了简要的总结。     

Progress in Executive-Function Research: From Tasks to Functions to Regions to Networks

ABSTRACT— It has long been observed that damage to the frontal cortex affects a person's ability to control thought, behavior, and emotion while sometimes leaving fundamental processes such as vision, hearing, and long-term memory intact. Such observations have led theoreticians to suppose that a set of executive control functions exists, at the top of the hierarchy of mental processes. To study these executive functions and their relation to the frontal cortex and its subregions, researchers have long employed several now-classic cognitive tests in patients with brain damage. Yet until recently it has proved difficult to reliably localize the putative executive functions to discrete regions. This article illustrates how recent progress in executive-functions research has been driven by the coupling of sophisticated neuroscience techniques with advances in experimental psychology. Taking examples from recent studies, it shows how experimental tasks may be decomposed into cognitive components that can be localized to discrete—but structurally connected—brain regions. What emerges is a new ontology for executive function in terms of which cognitive components exist and of how, and when, they are recruited during task performance.     

Using transcranial magnetic stimulation methods to probe connectivity between motor areas of the brain

Transcranial magnetic stimulation is increasingly used as a tool to explore cortical motor function in healthy subjects and in patients with neurological disease or injury. This review describes a “twin coil” TMS approach that allows investigation of time related changes in functional connectivity between primary motor cortex and other areas in preparation for a forthcoming movement. Investigations into premotor–motor interactions show that these are specific to the type of task that is performed as well as the muscles used to control the movement, allowing us to monitor information flow within motor networks with millisecond time resolution.     

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.     

Integrated memory for objects, places, and temporal order: evidence for episodic-like memory in mice

Human episodic memory refers to the recollection of an unique past experience in terms of what happened, and where and when it happened. Factoring out the issue of conscious recollection, episodic memory, even at the behavioral level, has been difficult to demonstrate in non-human mammals. Although, it was previously shown that rodents can associate what and when or what and where information given on unique trials, it proved to be difficult to demonstrate memory for what, where, and when simultaneously in mammals, without using extensive training procedures, which might induce semantic rather than episodic memory recall. Towards the goal of an animal model of human episodic memory we designed an three-trial object exploration task in which different versions of the novelty-preference paradigm were combined to subsume (a) object recognition memory, (b) the memory for locations in which objects were explored, and (c) the temporal order memory for object presented at distinct time points. We found that mice spent more time exploring two "old familiar" objects relative to two "recent familiar" objects, reflecting memory for what and when and concomitantly directed more exploration at a spatially displaced "old familiar" object relative to a stationary "old familiar" object, reflecting memory for what and where. These results suggest that during a single test trial the mice were able to (a) recognize previously explored objects, (b) remember the location in which particular objects were previously encountered, and (c) to discriminate the relative recency in which different objects were presented. According to the currently discussed behavioral criteria for episodic-like memory in animals, our results suggest that mice are capable to form such higher order memories.     

Mindfulness meditation and consciousness: An integrative neuroscientific perspective

Although mindfulness meditation has been practiced in the East for more than two millennia, Western scientific research and healthcare programs have only recently drawn their attention to it. Basically, the concept of mindfulness hinges on focusing on one’s own awareness at the present moment. In this review we analyze different hypotheses about the functioning and the cerebral correlates of mindfulness meditation. Since mindfulness is strictly associated with a particular state of consciousness, we also examine some of the most relevant theories that have been proposed as accounts of consciousness. Finally, we suggest that consciousness and mindfulness meditation can be integrated within a neuroscientific perspective, by identifying the brain areas which seem to play an essential role in both, namely the anterior cingulate cortex, posterior cingulate cortex, insula and thalamus.     

抑郁倾向对合作的影响：双人同步近红外脑成像研究

抑郁人群不但表现出注意、记忆等个体认知层面的负性偏向, 还伴随有明显的社会认知障碍。已有研究在抑郁对社会认知的影响方面还考察得不多。本研究采用囚徒困境范式考察抑郁倾向对社会合作的影响。结果显示, 高抑郁倾向组比低抑郁倾向组的合作率更低, 双侧背外侧前额叶的激活更弱, 抑郁对右侧背外侧前额叶及眶额叶的脑间同步性有调节作用; 低抑郁被试与低抑郁被试配对时右侧颞顶联合区脑间同步性强于高抑郁被试与高抑郁被试配对, 或者高抑郁被试与低抑郁被试配对时的右侧颞顶联合区脑间同步性, 该效应当且仅当双方的选择相同时显著。结果表明, 抑郁群体在社会奖赏加工、冲突控制及心理理论脑区均存在功能性缺陷, 这些结果为理解抑郁人群合作意愿下降提供了脑成像证据。     

Representations in the Human Prefrontal Cortex

ABSTRACT— The prefrontal cortex (PFC) in humans has been studied for more than a century, but many crucial questions about its functions remain unanswered. This paper will highlight a few key differences between human and animal PFCs, and between the human PFC (HPFC) and other parts of the human brain. We then make a case that the HPFC is critically important for executing behaviors over time and integrating disparate information from throughout the brain. Finally, we will focus on our position in the current debate regarding how the HPFC performs its functions and discuss future directions for research.     

Response-specific sources of dual-task interference in human pre-motor cortex

It is difficult to perform two tasks at the same time. Such performance limitations are exemplified by the psychological refractory period (PRP): when participants make distinct motor responses to two stimuli presented in rapid succession, the response to the second stimulus is increasingly slowed as the time interval between the two stimuli is decreased. This impairment is thought to reflect a central limitation in selecting the appropriate response to each stimulus, but not in perceptually encoding the stimuli. In the present study, it was sought to determine which brain regions are specifically involved in response selection under dual-task conditions by contrasting fMRI brain activity measured from a response selection manipulation that increased dual-task costs, with brain activity measured from an equally demanding manipulation that affected perceptual visibility. While a number of parieto-frontal areas involved in response selection were activated by both dual-task manipulations, the dorsal pre-motor cortex, and to a lesser extent the inferior frontal cortex, were specifically engaged by the response selection manipulation. These results suggest that the pre-motor cortex is an important neural locus of response selection limitation under dual-task situations.     

Layer and regional effects of environmental enrichment on the pyramidal neuron morphology of the rat

The environmental enrichment (EE) paradigm is widely used to study experience-dependent brain plasticity. Several studies have investigated functional and anatomical EE effects. However, as EE effects are different according to cerebral region, cortical layer, dendritic field and morphological index considered, a univocal characterization of neuronal morphological changes following rearing in enriched environments is lacking.Aim of the present study was to characterize in the rat the effects of EE on the neuronal morphology of frontal and parietal cortical regions, the main target areas of the stimulation provided by the paradigm. Male Wistar rats were housed in an enriched environment for 3.5 months from the 21st postnatal day. For the morphological analysis, biotinylated dextran amine (BDA)-labeled pyramidal neurons were selected from frontal (M1–M2) and parietal (S1–S2) cortical layers III and V. Apical and basal dendritic branching and spines were analyzed using the Sholl method.Results showed that EE increased branching and spines in both layers of frontal cortex, but had a greater effect on apical arborization. In parietal cortex, EE significantly affected branching and spines in layer III but not layer V neurons, in which only a tendency to be influenced by the rearing conditions was observed in basal arborization.It is hypothesized that these multifaceted morphological EE effects are connected to the heavy involvement of a sensory-motor circuit engaged in the guidance of voluntary action and in motor learning activated by EE stimulation.     

自尊的认知神经机制

自尊是个体对自己总体的情感性评价。自尊有助于促进个体的心理健康,帮助个体应对威胁,具有重要的适应价值。近年来随着社会认知神经科学的兴起,关于自尊的认知神经机制的研究日益增多,主要涉及三个方面:1)自尊与大脑的结构(如海马体积、前扣带回等区域的灰质体积)和功能(静息态下的默认网络活动以及脑区之间的功能联结性)存在一定的关联;2)自尊调节大脑对威胁的反应,与高自尊个体相比,低自尊个体面对威胁时产生更强的防御性反应,自尊通过影响个体面对威胁时的大脑活动帮助个体更好地应对威胁;3)自我评价过程涉及大脑前额叶、眶额叶、扣带回等多个脑区,自尊调节个体在自我评价过程中的大脑活动。总之,自尊作为个体重要的人格特质,与大脑的结构、功能以及活动状态等都具有一定的关系;这些发现在一定程度上揭示了自尊的神经机制,加深了对自尊及其功能的理解。     

Regulation of brain activity in the fusiform face and parahippocampal place areas in 7–11-year-old children

Developmental studies have demonstrated that cognitive processes such as attention, suppression of interference and memory develop throughout childhood and adolescence. However, little is currently known about the development of top-down control mechanisms and their influence on cognitive performance. In the present study, we used functional magnetic resonance imaging to investigate modulation of activity in the ventral visual cortex in healthy 7–11-year-old children and young adults. The participants performed tasks that required attention to either face (Fs task) or scene (Sf task) images while trying to ignore distracting scene or face images, respectively. A face-selective area in the fusiform gyrus (fusiform face area, FFA) and an area responding preferentially to scene images in the parahippocampal gyrus (parahippocampal place area, PPA) were defined using functional localizers. Children responded slower and less accurately in the tasks than adults. In children, the right FFA was less selective to face images and regulation of activity between the Fs and Sf tasks was weaker compared to adults. In the PPA, selectivity to scenes and regulation of activity, there according to the task demands were comparable between children and adults. During the tasks, children activated prefrontal cortical areas including the middle (MFG) and superior (SFG) frontal gyrus more than adults. Functional connectivity between the right FFA and left MFG was stronger in adults than children in the Fs task. Children, on the other hand, had stronger functional connectivity than adults in the Sf task between the right FFA and right PPA and between right MFG and medial SFG. There were no group differences in the functional connectivity between the PPA and the prefrontal cortex (PFC). Together the results suggest that, in 7–11-year-old children, the FFA is still immature, whereas the selectivity to scenes and regulation of activity in the PPA is comparable to adults. The results also indicated functional immaturity of the PFC in children compared to adults and weaker connectivity between the PFC and the rFFA, explaining the weaker regulation of activity in the rFFA between the Fs and Sf tasks.