左侧背外侧前额叶在程序性运动学习中的作用

程序性运动学习包括序列学习和随机学习。神经影像学研究表明背外侧前额叶皮层(DLPFC)和初级运动皮层(M1)在程序性运动学习中发挥重要作用,但DLPFC和M1之间的联通性及其与不同程序性运动学习的关系尚不明确。本研究采用连续反应时间任务,结合经颅磁刺激(TMS)方法,探讨左侧DLPFC到M1的联通性在不同程序性运动学习中的差异。实验1采用两连发TMS探测DLPFC到M1的最佳投射时间点;实验2,被试分为2组,分别进行序列学习和随机学习,在学习前、后采集行为学数据,以及M1的运动诱发电位和DLPFC-M1联通性的电生理学数据。行为学结果发现序列学习组的学习效果更佳;电生理学结果发现,两组被试学习前、后M1的运动诱发电位均未发生改变;在最佳时间投射点、适当刺激强度下,序列学习组DLPFC-M1联通性发生改变,且与学习成绩相关,而随机学习组没有改变。结果说明DLPFC到M1的联通性增强可能是序列学习成绩更佳的重要原因,这一结果从电生理角度为DLPFC在运动学习中的作用提供了重要证据。     

Neural correlates of intertemporal choice in aggressive behavior

People often have to make decisions between immediate rewards and more long-term goals. Such intertemporal judgments are often investigated in the context of monetary choice or drug use, yet not in regard to aggressive behavior. We combined a novel intertemporal aggression paradigm with functional neuroimaging to examine the role of temporal delay in aggressive behavior and the neural correlates thereof. Sixty-one participants (aged 18–22 years; 37 females) exhibited substantial variability in the extent to which they selected immediate acts of lesser aggression versus delayed acts of greater aggression against a same-sex opponent. Choosing delayed-yet-more-severe aggression was increased by provocation and associated with greater self-control. Preferences for delayed aggression were associated with greater activity in the ventromedial prefrontal cortex (VMPFC) during such choices, and reduced functional connectivity between the VMPFC and brain regions implicated in motor impulsivity. Preferences for immediate aggression were associated with reduced functional connectivity between the VMPFC and the frontoparietal control network. Dispositionally aggressive participants exhibited reduced VMPFC activity, which partially explained and suppressed their preferences for delayed aggression. Blunted VMPFC activity may thus be a neural mechanism that promotes reactive aggression towards provocateurs among dispositionally aggressive individuals. These findings demonstrate the utility of an intertemporal framework for investigating aggression and provide further evidence for the similar underlying neurobiology between aggression and other rewarding behaviors.     

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.     

The role of dorsolateral prefrontal function in relationship commitment

Commitment is an important determinant of relationship stability. Previous studies demonstrated that relationship stability is influenced by several personality variables, one of which is conscientiousness. To account for the influence of conscientiousness on relationship stability, we propose a neurological model of commitment. The model assumes that conscientiousness and commitment are influenced by individual differences in anterior and mid-dorsolateral prefrontal (amDLPFC) functioning, and that conscientiousness is a partial mediator of the association between amDLPFC functioning and commitment. Results from two studies with dating couples are consistent with this model. Study 2 suggests that, relative to other conscientiousness facets, self-efficacy is a more likely mediator of the effect of amDLPFC functioning on commitment.     

背外侧前额叶对主动遗忘负性社会反馈的作用：针对抑郁症的TMS研究

抑郁症患者的负性心境可能源于其抑制功能障碍。患者在主动遗忘负性材料时无法有效调用背外侧前额叶(the dorsolateral prefrontal cortex, DLPFC)等负责抑制控制的额叶脑网络。同时, 患者对社会信息的加工比对非社会信息的加工存在更明显的认知神经障碍, 很难主动遗忘对自己不利的社会反馈信息。为了提高抑郁症患者对负性社会反馈的主动遗忘能力, 本研究采用经颅磁刺激技术(transcranial magnetic stimulation, TMS), 考察抑郁症患者在左侧(n = 32)或右侧DLPFC (n = 30)被激活后其记忆控制能力的改变。结果表明, 当患者的DLPFC被TMS激活时, 他们对社会拒绝的回忆正确率与健康对照组(n = 31)无差异, 且TMS激活右侧DLPFC还改善了患者对他人的社会态度。本研究是采用TMS提高抑郁症患者主动遗忘能力的首次尝试, 研究结果不但支持了DLPFC与记忆控制功能的因果关系, 还为临床治疗抑郁症、创伤后应激障碍、药物成瘾等患者的记忆控制缺陷提供了明确的神经靶点。     

Differential involvement of left prefrontal cortex in inductive and deductive reasoning

While inductive and deductive reasoning are considered distinct logical and psychological processes, little is known about their respective neural basis. To address this issue we scanned 16 subjects with fMRI, using an event-related design, while they engaged in inductive and deductive reasoning tasks. Both types of reasoning were characterized by activation of left lateral prefrontal and bilateral dorsal frontal, parietal, and occipital cortices. Neural responses unique to each type of reasoning determined from the Reasoning Type (deduction and induction) by Task (reasoning and baseline) interaction indicated greater involvement of left inferior frontal gyrus (BA 44) in deduction than induction, while left dorsolateral (BA 8/9) prefrontal gyrus showed greater activity during induction than deduction. This pattern suggests a dissociation within prefrontal cortex for deductive and inductive reasoning.     

Testing the involvement of the prefrontal cortex in lucid dreaming: A tDCS study

Recent studies suggest that lucid dreaming (awareness of dreaming while dreaming) might be associated with increased brain activity over frontal regions during rapid eye movement (REM) sleep. By applying transcranial direct current stimulation (tDCS), we aimed to manipulate the activation of the dorsolateral prefrontal cortex (DLPFC) during REM sleep to increase dream lucidity. Nineteen participants spent three consecutive nights in a sleep laboratory. On the second and third nights they randomly received either 1 mA tDCS for 10 min or sham stimulation during each REM period starting with the second one. According to the participants’ self-ratings, tDCS over the DLPFC during REM sleep increased lucidity in dreams. The effects, however, were not strong and found only in frequent lucid dreamers. While this indicates some preliminary support for the involvement of the DLPFC in lucid dreaming, further research, controlling for indirect effects of stimulation and including other brain regions, is needed.     

Physical home environment is associated with prefrontal cortical thickness in adolescents

Biologically embedded experiences alter developmental trajectories in ways that can influence health, learning, and/or behavior. These systematic differences in experiences may contribute to different biological outcomes as individuals grow and develop, including at the neural level. Previous studies of biologically embedded experiences on neurodevelopment have focused on large‐scale institutional or economic factors (e.g. socioeconomic status [SES]) and psychosocial factors (e.g. caregiving behavior). Less attention has focused on how the quality of the immediate home settings, such as the physical home environment (PHYS), influences neurodevelopment. Moreover, no study has investigated these effects in adolescents, who undergo significant physical maturation and neurodevelopment that may influence how they respond to their physical environments. The goal of the current study was to examine whether PHYS quality is biologically embedded in the developing adolescent brain as evidenced by cognitive achievement and cortical development in 56 (48% female) healthy adolescents (14–18 years (M = 16.83 years, SD = 1.17). Using in‐home assessments of the physical home environment, anatomical brain scans, and indices of academic achievement, we found that adolescents who have more physical problems in the home (e.g. structural hazards, crowding, excessive noise, poorly lit) have thinner prefrontal cortices, which was associated with lower levels of reading achievement, independent of SES and psychosocial factors. By conducting home visits to assess physical characteristics of adolescents’ home, we highlight a typically overlooked aspect of the home environment that has relevance for adolescents’ cognitive and brain development.     

Stages in the development of aggressive behavior in early childhood

Primary manifestations of aggression appear in the behavior of children in the second half of the first year of life. The frequency of Occurrence of interpeer aggression increases with age, and reaches its maximum in the third year. The frequency of aggression may later decrease, but there are considerable individual differences. Changes a h Occur in the form in which aggression is manifested; its motivational background and associated elicitors; its direction, duration, timing, and other operational characteristics, and in the modes of its acquisition. A certain continuity may be traced, however, in any of these features and the development of aggression may be perhaps more adequately represented by the following sequence of developmental stage:

• 1 Stage of preaggressive behavior;
• 2 Stage of primary differentiation;
• 3 Stage of the appearance of the individual pattern of aggressive behavior;
• 4 Stage of secondary differentiation of aggression;
• 5 Stage of the beginning of the transition into covert behavior—internalization of aggression

These stages represent certain facets of the interaction between the changing behavioral performance of the child and herlhis social environment, and may be used for evaluating aggressive behavior in young children.     

Instrumental conditioning of aggressive behavior in rats

A method has been developed for bringing an aggressive response under stimulus control. It was found that the number of conditioned aggyessive responses was maximal when low-weight target rats were used. The latencies of the conditioned responses toward target animals of 124 gm were significantly lower than those toward animals of 221 and 284 gm. The application of an extinction procedure on the conditioned aggressive response substantially increased the total number of emitted aggressive responses.     

Cognitive performance,monetary incentive,and aggression

Individuals with impaired cognitive abilities associated with frontal lobe function have recently been shown to manifest increased aggression. This study investigated the effect of contingent money to inhibit aggression in these individuals. One hundred and forty males, aged 18–40, were ranked according to their performance on the Spatial Conditional Associative-Learning task. Forty-eight males (24 with scores in each of the upper and lower performance quartiles) participated in the full study. Half of the subjects competed in a Taylor aggression task where they received a monetary incentive for choosing lower shocks; the remainder competed without any monetary contingency. Aggression was defined as shock intensity delivered to a sham opponent. Shock intensity significantly increased as a main effect of lower cognitive performance, absence of monetary incentive, and provocation. In addition, provocation interacted significantly with test performance. Finally, individuals in the upper cognitive performance quartile showed significantly greater reductions of unprovoked aggression in response to monetary incentive. The results are discussed in terms of impairments in the ability to associate inhibitory influences in the formulation of behavioral strategies under aggressive conditions. © 1996 Wiley-Liss, Inc.     

前额叶在老年阶段的可塑性及相关机制

大量研究表明, 前额叶的结构和功能更容易受年老化影响; 然而, 近年来的研究发现, 前额叶的结构和功能在老年阶段具有一定的可塑性。对老年人进行认知训练, 能够延缓前额叶皮层厚度的萎缩, 提高白质完整性, 改善神经网络的功能连接和分化, 并可能通过调节多巴胺系统的活动改变前额叶皮质和皮质下结构的功能激活模式。有氧锻炼能够改善心脑血管功能, 保护和促进神经元的存活和生长, 引起前额叶灰质、白质体积的增加及功能激活的变化。认知训练与有氧锻炼等相结合的整合性训练不仅引起前额叶及相关认知功能的改变, 而且具有更好的生态学效度, 使老年人日常认知能力和生活质量得到提高。未来研究应采用多种技术手段, 从多个层面理解老年阶段前额叶的可塑性及相关机制; 加强对与前额叶关系密切的多种认知功能可塑性神经机制的研究; 并重视与整合性训练有关的前额叶可塑性。     

大脑皮层-背侧纹状体通路在吗啡强迫性觅药和用药行为中的作用

药物成瘾是以强迫性觅药和用药行为为核心特征的慢性脑疾病。从初始用药到强迫性用药是成瘾者的觅药行为从目标导向性向习惯化发展的过程。强迫性觅药和用药行为是依赖于背外侧纹状体的习惯化行为, 同时前额叶皮层-背内侧纹状体通路对行为的控制减弱, 导致感觉运动皮层-背外侧纹状体通路对行为的控制持续占主导地位, 是成瘾行为具有强迫性特征的重要神经基础。本项目围绕这一重要问题展开研究, 在建立具有成瘾特征的动物模型的基础上, 采用行为学、行为药理学和组织形态学等方法揭示皮层-纹状体通路在强迫性觅药和用药行为中的作用。研究结果有望为进一步寻找该神经网络参与成瘾行为的分子机制提供重要线索。     

Characterization of aggressive behavior and phenytoin response

Recent work has suggested that the success of pharmacological treatment for chronic aggressive behavior may depend, in part, on the subtype of aggressive behavior displayed (e.g. reactive, impulsive aggression vs. predatory, premeditated aggression). The present study examined the usefulness of characterizing aggressive behavior during a 16‐week double‐blind crossover study of phenytoin (PHT) treatment in 41 aggressive adult males. The Impulsive/Premeditated Aggression Scales (IPAS) were used to characterize aggressive behavior as predominantly impulsive or predominantly premeditated in nature. Analyses indicated that participants who did not respond to PHT treatment endorsed significantly more premeditated characteristics on the IPAS than those who responded to PHT treatment. Non‐responders also exhibited fewer aggressive outbursts during placebo treatment, suggesting a greater level of behavior control. Participants who did not complete the study were younger, endorsed significantly more premeditated aggression characteristics and reported more lifetime antisocial behaviors than those who completed the study. Taken together, these data emphasize several factors that may influence the success of pharmacological treatment in aggressive individuals, namely the importance of characterizing the predominant type of problem aggressive behavior. Aggr. Behav. 00:1–6, 2005. © 2005 Wiley‐Liss, Inc.     

Intellectual ability and aggressive behavior in nonclinical-nonforensic males

The purpose of this study was to test the relationship between IQ and physical aggression in a nonclinical-nonforensic male sample in a laboratory setting. Thirty males completed an abbreviated version of the Wechsler Adult Intelligence Scale—Revised. Aggression was measured using a modified version of the Taylor reaction-time (RT) aggression paradigm in which subjects competed on a RT task and both received and delivered shocks to a fictitious opponent in provoking and nonprovoking conditions. Provocation conditions (High and Low) were defined by the intensity of shocks the subjects received. Results demonstrated strong inverse correlations between IQ and aggressive behavior under both High and Low Provocation conditions.     

Functions of the vibrissae in the defensive and aggressive behavior of the rat

Removal of mystacial vibrissae for strange rats placed in an established rat colony produced reliable decrements in defensive boxing for these animals, and corresponding increases in freezing. In a subsequent experiment, removal of the vibrissae of the attacking colony males did not change the attack behavior of the vibrissectomized animals. These results indicate that the vibrissae are involved in defensive boxing behavior, but play no essential role in the elicitation or maintenance of conspecific attack in the rat.     

经颅直流电刺激在注意缺陷多动障碍治疗中的应用

经颅直流电刺激(tDCS)治疗注意缺陷多动障碍(ADHD)主要是选取患者的背外侧前额叶(DLPFC)作为刺激区域, 通过调节其皮层兴奋性, 从而缓解其ADHD的症状和改善其受损的认知功能。针对tDCS在ADHD治疗研究中的问题, 未来可从有效性、确定最佳刺激参数、个体差异、不同亚型及与其他疗法联合使用等五个方面来进一步研究。