Resource scarcity aggravates ingroup bias: Neural mechanisms and cross-scenario validation

Previous studies examining the relationship between ingroup bias and resource scarcity have produced heterogeneous findings, possibly due to their focus on the allocation of positive resources (e.g. money). This study aims to investigate whether ingroup bias would be amplified or eliminated when perceived survival resources for counteracting negative stimuli are scarce. For this purpose, we exposed the participants and another confederate of the experimenters (ingroup/outgroup member) to a potential threat of unpleasant noise. Participants received some ‘relieving resources’ to counteract noise administration, the amount of which may or may not be enough for them and the confederate in different conditions (i.e. abundance vs. scarcity). First, a behavioural experiment demonstrated that intergroup discrimination manifested only in the scarcity condition; in contrast, the participants allocated similar amounts of resource to ingroup and outgroup members in the abundance condition, indicating a context-dependent allocation strategy. This behavioural pattern was replicated in a follow-up neuroimaging experiment, which further revealed that when contrasting scarcity with abundance, there was higher activation in the anterior cingulate cortex (ACC) as well as stronger functional connectivity of the ACC with the empathy network (including the temporoparietal junction and medial prefrontal cortex) for ingroup compared to outgroup members. We suggest that ACC activation reflects the mentalizing process toward ingroup over outgroup members in the scarcity condition. Finally, the ACC activation level significantly predicted the influence of resource scarcity on ingroup bias in hypothetical real-life situations according to a follow-up examination.     

长期高策略性技能训练对运动员大脑白质结构的影响：一项DTI研究

目前关于运动员经验优势的脑机制还存在争议, 尤其对于涉及较多认知过程参与的高策略性技能项目运动员, 其大脑白质结构可塑性变化还需进一步探究。研究横向对比了乒乓球运动员和非运动员大脑白质纤维束的弥散张量成像数据。结果发现, 相比于非运动员, 乒乓球运动员在连接背侧和腹侧通路脑区的双侧皮质脊髓束、左侧上纵束、左侧下纵束和双侧额枕下束的各向异性值(FA)更大, 进一步分析发现, 部分腹侧通路白质纤维束FA增加的原因是径向扩散系数(RD)下降。研究结果支持了动作双通路模型。提示经过长期高策略性技能训练, 乒乓球运动员在背侧和腹侧通路上的白质纤维束结构完整性增强。     

计算模型视角下信任形成的心理和神经机制——基于信任博弈中投资者的角度

人际信任渗透在社会交互的各个方面, 是促进和维持合作的重要基石。以往研究者借助信任博弈范式, 主要探讨了人际信任的理论模型、生物基础和影响因素等方面。近年来, 研究者开始将计算模型应用于信任博弈的数据分析中, 深入挖掘人际信任行为背后的心理机制, 将计算模型与神经影像技术结合, 加深对信任行为背后脑机制的理解。目前将计算模型应用于信任博弈范式中的研究主要针对“信任是如何形成的”这一科学问题, 未来要进一步发展计算模型方法, 结合非侵入性脑刺激技术, 应用于精神疾病人群中, 以深入理解正常和异常信任形成的心理和神经机制。     

睡眠剥夺对风险决策的影响机制探讨

许多行业的决策者必须在睡眠不足的状态下做出选择与判断。睡眠剥夺是睡眠不足的实验室模型, 被证明能显著影响风险决策, 但内在机制不明。基于前人研究基础提出假设模型, 即睡眠剥夺通过影响个体的反馈加工、风险感知、抑制控制、决策理性, 进而影响风险决策。拟通过实验室研究与现场研究, 采用简单赌博任务、概率折扣任务、双选择Oddball任务等研究范式, 对比睡眠剥夺前后被试在执行上述实验任务时的行为差异, 同时比较执行控制网络、奖赏网络等脑功能网络连接强度, 以及任务诱发的FRN等脑电成分在睡眠剥夺前后的变化, 进而论证上述反应被试反馈加工等心理过程的行为-脑电-脑成像指标的变化与睡眠剥夺后被试风险决策变化的关系。研究结果将科学地解释睡眠剥夺影响风险决策的内在机制, 为进一步探讨如何规避睡眠不足导致的决策失误提供理论与实证依据。     

Operant-contingency-based preparation of children for functional magnetic resonance imaging

Functional magnetic resonance imaging (fMRI) is used to study brain function during behavioral tasks. The participation of pediatric subjects is problematic because reliable task performance and control of head movement are simultaneously required. Differential reinforcement decreased head motion and improved vigilance task performance in 4 children (2 with behavioral disorders) undergoing simulated fMRI scans. Results show that behavior analysis techniques can improve child cooperation during fMRI procedures.     

Frontal-Lobe Involvement in Spatial Memory: Evidence from PET,fMRI, and Lesion Studies

Many studies have identified the prefrontal cortex as the brain area that is critical for spatial memory, both in humans and in other primates. Other studies, however, have failed to establish this relation. Therefore, the aim of this paper was to review the literature regarding the role of the human prefrontal lobe in spatial memory. This was done by examining the evidence obtained from neuropsychological patients and from studies using brain-imaging techniques (PET and fMRI). Evidence supporting the notion that the prefrontal cortex is extensively involved in spatial working memory was found. The majority of these studies, however, suggests that frontal-lobe involvement is not related to the type of material that is being processed (e.g., spatial vs. nonspatial), but to process-specific functions, such as encoding and retrieval. Theoretically, these functions could be linked to the central executive within Baddeley's working-memory model, or to recent theories that emphasize the various processes that play a role in working memory. Also, methodological issues were discussed. Further research is needed to enhance our understanding of the precise interaction of domain-specific and general processes.     

Prefrontal brain activity predicts temporally extended decision-making behavior

Although functional neuroimaging studies of human decision-making processes are increasingly common, most of the research in this area has relied on passive tasks that generate little individual variability. Relatively little attention has been paid to the ability of brain activity to predict overt behavior. Using functional magnetic resonance imaging (fMRI), we investigated the neural mechanisms underlying behavior during a dynamic decision task that required subjects to select smaller, short-term monetary payoffs in order to receive larger, long-term gains. The number of trials over which the longterm gains accrued was manipulated experimentally (2 versus 12). Event-related neural activity in right lateral prefrontal cortex, a region associated with high-level cognitive processing, selectively predicted choice behavior in both conditions, whereas insular cortex responded to fluctuations in amount of reward but did not predict choice behavior. These results demonstrate the utility of a functional neuroimaging approach in behavioral psychology, showing that (a) highly circumscribed brain regions are capable of predicting complex choice behavior, and (b) fMRI has the ability to dissociate the contributions of different neural mechanisms to particular behavioral tasks.     

2003年诺贝尔医学奖给科学界的多重启示(上)

2003年诺贝尔医学奖授予了两位美英物理学家,劳特布尔和曼斯菲尔德,表彰他们在磁共振成像方面的发现.这些发现导致现代磁共振技术的开发,这一技术标志着医学诊断学和科学研究中的一项突破.该项发现建筑在核磁和核磁共振现象被发现的基础之上.核磁现象的发现及其应用导致了1943、1944和1952年诺贝尔物理学奖的获得.核磁共振现象的发现及其应用导致了1991年和2002年诺贝尔化学奖的获得.这意味着,2003年诺贝尔医学奖是该系列发现中第六个诺贝尔科学奖.     

Co-localisation of abnormal brain structure and function in specific language impairment

We assessed the relationship between brain structure and function in 10 individuals with specific language impairment (SLI), compared to six unaffected siblings, and 16 unrelated control participants with typical language. Voxel-based morphometry indicated that grey matter in the SLI group, relative to controls, was increased in the left inferior frontal cortex and decreased in the right caudate nucleus and superior temporal cortex bilaterally. The unaffected siblings also showed reduced grey matter in the caudate nucleus relative to controls. In an auditory covert naming task, the SLI group showed reduced activation in the left inferior frontal cortex, right putamen, and in the superior temporal cortex bilaterally. Despite spatially coincident structural and functional abnormalities in frontal and temporal areas, the relationships between structure and function in these regions were different. These findings suggest multiple structural and functional abnormalities in SLI that are differently associated with receptive and expressive language processing.     

Brain activity in adults who stutter: similarities across speaking tasks and correlations with stuttering frequency and speaking rate

Many differences in brain activity have been reported between persons who stutter (PWS) and typically fluent controls during oral reading tasks. An earlier meta-analysis of imaging studies identified stutter-related regions, but recent studies report less agreement with those regions. A PET study on adult dextral PWS (n = 18) and matched fluent controls (CONT, n = 12) is reported that used both oral reading and monologue tasks. After correcting for speech rate differences between the groups the task-activation differences were surprisingly small. For both analyses only some regions previously considered stutter-related were more activated in the PWS group than in the CONT group, and these were also activated during eyes-closed rest (ECR). In the PWS group, stuttering frequency was correlated with cortico-striatal-thalamic circuit activity in both speaking tasks. The neuroimaging findings for the PWS group, relative to the CONT group, appear consistent with neuroanatomic abnormalities being increasingly reported among PWS.