刺激放置朝向对返回抑制的影响:一项ERPs研究

返回抑制(inhibition of return, IOR)是指个体对出现在先前提示位置上的刺激反应更慢的现象。尽管大量ERPs研究发现呈现在线索化和非线索化位置上的靶刺激诱发的ERPs在250-300ms处存在一个稳定的差异(Nd250),但这一差异的方向却并不一致。本研究采用事件相关电位技术(Event-related Potentials, ERPs),结合经典的线索-靶子范式,考察刺激放置的朝向是否会影响到IOR中Nd250效应的极性。结果显示虽然刺激放置朝向并未有影响到Nd250的极性,却对早期P1成分的线索化效应的地形图分布有着显著的影响。这表明1）过往ERPs研究中的Nd250效应极性的不一致并非源于刺激放置朝向的作用;2）刺激的放置朝向会导致早期线索化效应(P1)在地形分布上出现差异。     

揭示大脑奥秘的新途径:还原论与整合论的有机融合

脑科学研究经历了简单的整合论,到简单的还原论,发展到成熟的还原论,以及成熟的整合论,最终认知神经科学的延生标志着还原论与整合论的有机融合进入新阶段.认知神经科学强调多学科、多层次、多水平的交叉,研究的层次包括分子、突触、神经元、网络、脑区、系统、全脑及整体行为乃至环境、社会等.     

练习促进内隐策略生成：其发生过程及应用特点

本研究通过设置隐含算术策略的问题情境,比较不同顺序和设置条件的进程段行为反应和ERP数据差异,考察被试在不断练习条件下对隐含策略的习得过程及迁移应用特点。结果：被试在对隐含策略无意识的情况下,第1-4练习进程段的反应时、错误率显著低于第5进程段（探测段）。同时,不同进程段诱发的部分ERPs特征也呈现有规律的变化。结论：在存在隐含策略的算术策略任务情境中,通过练习人们可以在无意识情况下逐渐生成内隐策略,诱发的ERP成分P200、N400s可以部分地反映其生成过程。已生成的内隐策略,能部分地应用到相应的新情境中。     

Functional Neuroimaging and the Law: Trends and Directions for Future Scholarship

Under the umbrella of the burgeoning neurotransdisciplines, scholars are using the principles and research methodologies of their primary and secondary fields to examine developments in neuroimaging, neuromodulation and psychopharmacology. The path for advanced scholarship at the intersection of law and neuroscience may clear if work across the disciplines is collected and reviewed and outstanding and debated issues are identified and clarified. In this article, I organize, examine and refine a narrow class of the burgeoning neurotransdiscipline scholarship; that is, scholarship at the interface of law and functional magnetic resonance imaging (fMRI).     

Accelerative and decelerative effects of hedonic valence and emotional arousal during visual scene processing

Perceptual processing of natural scene pictures is enhanced when the scene conveys emotional content. Such “motivated attention” to pleasant and unpleasant pictures has been shown to improve identification accuracy in non-speeded behavioural tasks. An open question is whether emotional content also modulates the speed of visual scene processing. In the present studies we show that unpleasant content reliably slowed two-choice categorization of pictures, irrespective of physical image properties, perceptual complexity, and categorization instructions. Conversely, pleasant content did not slow or even accelerated choice reactions, relative to neutral scenes. As indicated by lateralized readiness potentials, these effects occurred at cognitive processing rather than motor preparation/execution stages. Specifically, analysis of event-related potentials showed a prolongation of early scene discrimination for stimuli perceived as emotionally arousing, regardless of valence, and reflected in delayed peaks of the N1 component. In contrast, the timing of other processing steps, reflected in the P2 and late positive potential components and presumably related to post-discriminatory processes such as stimulus–response mapping, appeared to be determined by hedonic valence, with more pleasant scenes eliciting faster processing. Consistent with this model, varying arousal (low/high) within the emotional categories mediated the effects of valence on choice reaction speed. Functionally, arousal may prolong stimulus analysis in order to prevent erroneous and potentially harmful decisions. Pleasantness may act as a safety signal allowing rapid initiation of overt responses.     

Psychobiological Treatment Response to a Two-Week Posttraumatic Stress Disorder and Mild Traumatic Brain Injury Integrated Treatment Program: A Case Report

Posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI) demonstrate high prevalence and comorbidity among post-9/11 veterans. Veterans with this comorbidity often present with multiple co-occurring healthcare needs and increased clinical complexity. The current case report describes the clinical presentation of a veteran with mild TBI and PTSD, both before, during, and after treatment within a multidisciplinary 2-week intensive outpatient program involving prolonged exposure, evidence-based PTSD treatment, and Cognitive Symptom Management and Rehabilitation Therapy, evidence-based treatment for postconcussive symptoms. Mr. A was a 25-year-old White, transgender male who presented with a complex mental health history. At intake, presenting complaints included anxiety, panic attacks, nightmares, and depression secondary to military sexual trauma, as well as reported cognitive difficulties secondary to a concussion. He met current criteria for PTSD as well as panic disorder with agoraphobia. Head injury history consisted of a motor vehicle collision with less than 30 seconds loss of consciousness, brief posttraumatic amnesia, and alterations of consciousness. Mr. A demonstrated habituation during individual exposure sessions as assessed via skin conductance during imaginal exposures and decreased subjective ratings during in vivo exposures, as well as a decrease in trauma-potentiated startle response to trauma cues. Posttreatment data indicates significant reduction in neurobehavioral, posttraumatic stress, and depression symptoms and significant improvement in subjective cognitive functioning. The current findings support the feasibility and efficacy of short-term integrated treatment for complex clinical presentations and the need for larger scale research investigating combined PTSD and TBI intervention.     

An Analogue Study of the Psychological and Psychosocial Processes Associated With Post‐concussion Symptoms

This study used an analogue design to investigate post‐concussion syndrome and the psychological and psychosocial processes associated with post‐concussion symptom (PCSx) reporting. The study examined the role of expectation in reporting of PCSx, the nature of associated psychological and psychosocial difficulties, and the “good‐old‐days” phenomenon. Forty‐five healthy participants were randomly assigned to one of two groups: (1) a control group or (2) an expectation group who were asked to perform as if they had experienced a mild traumatic brain injury. Fourteen psychiatric patients comprised the clinical group. Self‐report questionnaires assessing PCSx and psychological and psychosocial variables were administered. It was hypothesised that PCSx would be non‐specific, that the expectation group would report greater dysfunction than controls, and that the “good‐old‐days” phenomenon would cause the expectation and clinical groups to underestimate pre‐morbid PCSx. All participants reported some degree of dysfunction, and the expectation and clinical groups underestimated past PCSx. The expectation group reported more PCSx and psychological and psychosocial dysfunction than controls, resembling the clinical group. The results demonstrate that expectation can cause otherwise healthy individuals to resemble a clinical group in terms of their level of endorsement of psychological and psychosocial dysfunction.     

When does the brain distinguish between genuine and ambiguous smiles? An ERP study

Event-related brain potentials (ERPs) were recorded to assess the processing time course of ambiguous facial expressions with a smiling mouth but neutral, fearful, or angry eyes, in comparison with genuinely happy faces (a smile and happy eyes) and non-happy faces (neutral, fearful, or angry mouth and eyes). Participants judged whether the faces looked truly happy or not. Electroencephalographic recordings were made from 64 scalp electrodes to generate ERPs. The neural activation patterns showed early P200 sensitivity (differences between negative and positive or neutral expressions) and EPN sensitivity (differences between positive and neutral expressions) to emotional valence. In contrast, sensitivity to ambiguity (differences between genuine and ambiguous expressions) emerged only in later LPP components. Discrimination of emotional vs. neutral affect occurs between 180 and 430 ms from stimulus onset, whereas the detection and resolution of ambiguity takes place between 470 and 720 ms. In addition, while blended expressions involving a smile with angry eyes can be identified as not happy in the P200 (175–240 ms) component, smiles with fearful or neutral eyes produce the same ERP pattern as genuinely happy faces, thus revealing poor discrimination.     

决策中后悔的ERP研究

采用运气轮博弈范式探讨后悔的加工时程。分析决策正误的ERPs发现,200～300ms决策错误比正确诱发更为负走向的波,表现为典型的FRN（feedback-related negativity, FRN）;300～400ms决策正确比错误诱发更大的P300。500～900ms决策正确比错误诱发更大的LPC（late positive component, LPC）,并表现出明显的右半球优势效应。上述结果支持了FRN加工反馈刺激显著性信息和P300加工反馈刺激效价的观点,研究发现后悔与LPC可能具有密切关联。将来研究须在控制得失程度基础上,考察FRN、P300和LPC与效价、得失及得失程度和情绪体验的关系。     

Transcranial Doppler Ultrasonography Monitoring of Cerebral Hemodynamics During Performance of Cognitive Tasks: A Review

The examination of blood flow velocity (BFV) changes during the performance of mental tasks is one of the applications of transcranial Doppler (TCD) ultrasonography. The purpose of this review is to summarize the results of the functional TCD literature, to investigate the effects of methodological differences between studies, and to provide guidelines for future research. It is concluded that larger series of more homogeneous groups concerning age and handedness, and stricter criteria for subject selection and laboratory setting are required. The implication of quantitative and qualitative performance measures and psychological parameters (motivation, anxiety, and task anticipation) could also yield important information. We recommend future agreement upon a more standardized methodology. TCD promises to be a useful tool to provide further insight into the cerebral organization and temporal reactivity of the human brain.