孤独症谱系障碍者的生物运动探测障碍：基于行为与神经的证据

关于孤独症谱系障碍(autism spectrum disorder, ASD)个体探测生物运动(biological motion)的能力是否受损,已有行为研究尚存分歧。导致分歧的原因可能源于实验刺激、实验任务和测量指标存在差异。然而,神经研究却一致证实其潜在的神经机制存在异常。领域特殊性观点认为该障碍可能是基于后侧颞上沟功能异常也可能是基于镜像神经元功能异常,而领域一般性观点认为该障碍可能是基于背侧视觉流功能异常的视运动知觉障碍也可能基于脑功能联结异常的弱中央统合障碍。据此,本文将从研究范式、行为表现及潜在机制三个方面梳理相关研究,以期为后续研究提供新方向。     

自闭谱系障碍对视线的加工

视线加工异常是自闭谱系障碍(简称ASD)的一个显著特征。该特征出现在发育的早期,并且与社会互动、人际交往功能障碍有关。本综述主要聚焦于ASD视线加工中的眼睛关注、眼神分辨、视线追踪以及共同注意四个方面,全面述评了ASD视线加工的行为以及脑功能的研究成果。文章也对ASD视线加工异常的机制以及未来的研究进行了讨论和展望。     

音乐绝对音高信息加工的脑机制

音乐绝对音高(absolute pitch, AP)一直是音乐心理学者感兴趣的问题。AP能力是一种特殊的音乐能力。ERP研究表明具有AP能力的群体只需较少的认知资源进行音高加工, 同时不同AP能力的加工机制也不同; 功能神经成像研究表明大脑左侧额叶背侧后部和左侧颞叶平面对AP加工发挥重要作用; 脑结构研究发现AP群体的某些脑区皮层厚度低于没有绝对音高能力(Non-AP)群体, 这可能与AP特殊的加工机制有关。AP能力形成需要先天遗传和后天环境的共同作用, 其相互作用的脑机制需结合行为遗传学的研究方法及成果。     

发展性阅读障碍与知觉加工

近年来许多行为实验和神经生理学实验都发现 ,发展性阅读障碍与基本知觉障碍有关。在视觉领域研究者提出了巨细胞障碍假设 ,这种假设认为阅读障碍者视觉神经系统中的巨细胞障碍导致他们对某种类型的视觉刺激加工存在困难 ,进而影响阅读。在听觉领域研究发现阅读障碍者加工快速、系列、短暂呈现的声音刺激存在障碍。研究者认为阅读障碍者加工快速刺激输入障碍反映了普遍的时间知觉障碍。这方面的研究发展非常迅速 ,理论观点非常明确 ,并且直接与内在的神经机制相联系 ,形成了与传统的“语言障碍”理论迥然不同的“知觉障碍”理论。“知觉障碍”理论综合了行为、认知和神经等多个层次的研究 ,反映了神经科学发展所带来的巨大影响和认知加工模块化理论的渐渐衰退。     

孤独症儿童动作发展障碍的神经机制

动作发展障碍(Developmental motor disorders)是孤独症谱系障碍的常见特征。通过系统回顾孤独症儿童动作发展障碍的神经科学研究, 发现γ-氨基丁酸和5-羟色胺浓度的改变及γ-氨基丁酸相关蛋白和Shank蛋白的表达异常不仅会损害中枢神经系统的发育, 而且还能导致突触兴奋性与抑制性失衡, 进而改变孤独症儿童小脑和大脑皮层运动区的功能连接。孤独症儿童小脑、基底神经节和胼胝体结构的改变对全脑的连通性产生了负面影响。神经生化机制和脑结构的异常共同导致了脑功能的异常, 最终造成孤独症儿童的动作发展障碍。此外, 动作发展障碍与孤独症核心症状共同的神经基础主要包括镜像神经元系统紊乱, 丘脑、基底神经节和小脑异常以及SLC7A5和PTEN 基因突变。未来研究需要关注与运动密切相关的其他神经递质, 如乙酰胆碱和多巴胺; 探索动作发展障碍神经网络的动态机制及其形成; 剖析该障碍的神经机制和自闭症核心症状神经机制的相互作用。     

高功能自闭症个体对威胁性情绪面孔的注意偏向

高功能自闭症(High-Functioning Autism, HFA)个体智力正常, 但也面临着严重的社会功能障碍。对威胁性情绪面孔的注意偏向与HFA个体社会功能的发展密切相关。梳理相关研究发现, HFA个体在自动加工阶段和情绪目标参与阶段, 不存在威胁性情绪面孔注意偏向; 而在任务与情绪无关的控制加工阶段, 存在威胁性情绪面孔注意偏向。针对HFA个体威胁性情绪面孔注意偏向的理论解释主要有杏仁核理论、强烈世界理论和执行功能理论等。神经生理机制方面, HFA个体对威胁性情绪面孔的注意偏向可能与其异常的皮下及皮层通路功能有关, 同时可能会受5-羟色胺系统基因及催产素水平等的影响。未来研究可在综合考虑研究方法及个体因素的基础上, 进一步探究其加工特征及神经生物机制, 着力开发科学有效的干预策略。     

不同注意形式调节听感觉门控的神经机制

前脉冲抑制(prepulse inhibition, PPI)是听感觉门控的测量模型, 反映了听觉系统的早期信息选择功能。尽管PPI的主要神经环路位于脑干, 研究发现PPI可以被注意自上而下调节。然而, 已有研究并未区分不同注意(特征注意和空间注意)对PPI的特异性调节, 并且神经机制方面的研究集中于听皮层区域, 仍缺乏对皮层下机制的探讨。在以往研究的成果基础之上, 借助听觉信息加工的双通路模型, 采用行为测量、脑电和脑成像技术, 揭示特征和空间两种注意调节PPI的神经活动在听觉系统中的层次性神经表达。包括1)建立特征注意和空间注意调节PPI的统一行为模型, 考察两种注意调节PPI的时间动态性异同; 2)两种注意调节PPI的脑干分离机制, 即前脉冲刺激包络和精细结构成分加工在注意调节PPI中的作用差异; 3)两种注意调节PPI的关键脑区和脑网络差异。     

自伤行为的神经生理机制及共病障碍比较

非自杀性自伤行为（Non-Suicidal Self-Injury, NSSI）,简称自伤行为,意为个体在没有明确的自杀意图的情况下,故意、重复地改变或伤害自己的身体组织,是一种不具致死性或致死性较低的、以自身为伤害目标的破坏性行为。本文主要基于近十年的研究文献,从神经生理层面对自伤行为相关脑区、神经递质以及与共病障碍的异同展开述评,并尝试建立一个整合性的自伤行为认知神经机制模型。 关于自伤行为的神经生理机制,综合以往研究发现,自伤患者边缘系统中情绪脑区的异常（如杏仁核的过度激活等）使患者可能产生情绪调节障碍进而导致自伤;控制脑区如前额叶皮层的异常导致其抑制控制能力受损;奖赏脑区如眶额皮层等的过度激活或许会成为自伤复发的维持因素;自伤患者疼痛感知区域如HPA轴的反应水平的减弱使其疼痛敏感性较低并主动追寻疼痛感。除此之外,相关的神经递质和基因的异常也是自伤研究领域关注的重点。比如5-羟色胺转运体其基因连锁多态区的短等位基因会减弱该递质的调节功能,诱使个体出现情绪调节障碍;又比如内源性阿片肽参与了疼痛和情绪调节的过程,且其水平会因个体早期挫折经历和遗传因素而降低,而自伤行为可以促进该递质的释放;同样的,在阿片受体被刺激之后,自伤者体内的多巴胺水平将会升高,个体对自伤行为产生愉悦感。 此外,还将其与自杀、成瘾、进食障碍和抑郁障碍进行了比较。自伤和自杀尝试者在脑电指标上有某些不同的表现,但二者从行为研究和功能成像的角度也呈现出相似性。个体的自伤行为与物质成瘾显著相关,且二者都伴随着抑制控制能力的损伤、阿片类和多巴胺系统异常引发的对某种物质或行为的渴望等。进食障碍患者和自伤行为存在较高的共病率,前者可能就是一种间接的自伤,且二者的脑电和功能成像的指标部分相似。最后,抑郁障碍也是和自伤行为有着较高共病率的一种障碍,部分抑郁障碍患者会通过自伤来调节情绪,且二者有共同的风险因素以及部分重叠的神经机制。研究以上障碍与自伤行为的异同有助于我们从不同角度认识自伤,并多方位实施预警和干预。 在此基础上,本文尝试构建了自伤行为的认知神经机制假设模型,将自伤的认知过程与各阶段起主要作用的神经生理机制相联系。未来的研究可以关注于自伤行为的性别差异、发展特点、干预以及与注意脑区异常的联系等。     

孤独症者面孔加工中眼部注视不足,是回避还是忽视?

临床行为观察发现,孤独症谱系障碍(Autism Spectrum Disorder,简称ASD)个体在社会交往中较少注视他人眼部。近年的眼动研究发现,ASD个体面孔加工中的眼部注视不足随年龄增长而逐渐显现,与脑电技术相结合的眼动研究进一步发现ASD个体的面孔认知加工障碍与眼部注视不足存在关联。该障碍的潜在认知神经机制可能既源于原生性的杏仁核激活异常,也源于次生性的社会脑发展异常。然而,ASD个体的杏仁核是过度激活主动回避眼部还是激活不足被动忽视眼部尚无定论。今后研究者应横跨不同年龄阶段和不同研究层次,同时搜集眼动与神经生理数据,开展横向比较与纵向追踪相结合的相关研究。     

视觉意识及其神经机制

视觉意识的神经机制是当前认知神经科学研究的热点问题之一。过去普遍认为视觉信息加工主要有两条通路:腹侧通路和背侧通路;而新近的研究表明还存在不经过初级视觉皮层(V1区)的第三条通路。高级视觉皮层、V1区和皮层下结构都对意识觉知的产生起到了相应的作用。已有的实验证据表明,意识的产生过程异常复杂,仍有很多问题值得继续深入讨论和研究。     

Face-to-face interference in typical and atypical development

Visual communication cues facilitate interpersonal communication. It is important that we look at faces to retrieve and subsequently process such cues. It is also important that we sometimes look away from faces as they increase cognitive load that may interfere with online processing. Indeed, when typically developing individuals hold face gaze it interferes with task completion. In this novel study we quantify face interference for the first time in Williams syndrome (WS) and Autism Spectrum Disorder (ASD). These disorders of development impact on cognition and social attention, but how do faces interfere with cognitive processing? Individuals developing typically as well as those with ASD (n = 19) and WS (n = 16) were recorded during a question and answer session that involved mathematics questions. In phase 1 gaze behaviour was not manipulated, but in phase 2 participants were required to maintain eye contact with the experimenter at all times. Looking at faces decreased task accuracy for individuals who were developing typically. Critically, the same pattern was seen in WS and ASD, whereby task performance decreased when participants were required to hold face gaze. The results show that looking at faces interferes with task performance in all groups. This finding requires the caveat that individuals with WS and ASD found it harder than individuals who were developing typically to maintain eye contact throughout the interaction. Individuals with ASD struggled to hold eye contact at all points of the interaction while those with WS found it especially difficult when thinking.     

自闭症谱系障碍个体的社会动机缺陷

自闭症谱系障碍(ASD)是一种源于儿童期的神经发育障碍, 社会交往障碍是其核心特征, 与社会动机缺陷密切相关。社会动机是引导个体社会行为的强大动力, 主要表现为社会定向、社会奖赏和社会维持。现有研究表明, ASD个体的社会动机发展存在缺陷, 他们对社会刺激的注意偏向减少, 不能主动寻求和体会社会互动带来的快乐, 且缺乏维持社会关系的行为策略等。然而, 相关研究结果受到个体特征、环境和实验设计等因素的影响。研究者未来应综合考虑这些影响因素, 加强对ASD个体社会动机理论的整合研究, 以便全面系统地了解ASD个体的社会动机缺陷。     

Structural connectivity between the hippocampus and cortical/subcortical area relates to cognitive impairment in schizophrenia but not in mood disorders

Cognitive impairment in schizophrenia and other psychiatric disorders is a challenge to be overcome in order to maintain patients' quality of life and social function. The neurological pathogenesis of cognitive impairment requires further elucidation. In general, the hippocampus interacts between the cortical and subcortical areas for information processing and consolidation and has an important role in memory. We examined the relationship between structural connectivity of the hippocampus and cortical/subcortical areas and cognitive impairment in schizophrenia, major depressive disorder and bipolar disorder. Subjects comprised 21 healthy controls, 19 patients with schizophrenia, 20 patients with bipolar disorder and 18 patients with major depressive disorder. Diffusion-weighted tensor images data were processed using ProbtrackX2 to calculate the structural connectivity between the hippocampus and cortical/subcortical areas. Cognitive function was assessed using the Brief Assessment of Cognition in schizophrenia composite score. Hippocampal structural connectivity index was significantly correlated with composite score in the schizophrenia group but not in the healthy control, major depressive disorder or bipolar disorder groups. There were no statistically significant differences in hippocampal structural connectivity index between the four groups. Structural connectivity between the hippocampus and cortical/subcortical areas is suggested to be a pathophysiological mechanism of comprehensive cognitive impairment in schizophrenia.     

Controlling attention to gaze and arrows in childhood: an fMRI study of typical development and Autism Spectrum Disorders

Functional magnetic resonance imaging was used to examine functional anatomy of attention to social (eye gaze) and nonsocial (arrow) communicative stimuli in late childhood and in a disorder defined by atypical processing of social stimuli, Autism Spectrum Disorders (ASD). Children responded to a target word ('LEFT'/'RIGHT') in the context of a distracting arrow or averted gaze pointing in a direction that was congruent, incongruent, or neutral (bar without arrowheads, central gaze) relative to the target word. Despite being irrelevant to the target task, both arrow and averted gaze facilitated responses (Congruent vs. Neutral trials) to the same extent in the two groups and led to interference (Incongruent vs. Congruent trials), which was greater from arrows in ASD than control children. In the brain, interaction between group and distracter-domain was observed in frontal-temporal regions during facilitation and frontal-striatal regions during interference. During facilitation, regions associated with attention to gaze in control children (left superior temporal sulcus, premotor) were associated with attention to arrows in ASD children; gaze was associated with medial temporal involvement in ASD children. During interference, regions associated with arrows in control children (anterior cingulate, right caudate) were activated in response to gaze in ASD children; further, left dorsolateral prefrontal cortex, a region not observed in control children, was activated during gaze-interference in ASD children. Thus, functional anatomy was atypical in ASD children during spontaneous processing of social and nonsocial communicative cues.     

Anorexia nervosa and autism spectrum disorders: guided investigation of social cognitive endophenotypes

Death by suicide occurs in a disproportionate percentage of individuals with anorexia nervosa (AN), with a standardized mortality ratio indicating a 57-fold greater risk of death from suicide relative to an age-matched cohort. Longitudinal studies indicate impaired social functioning increases risk for fatal outcomes, while social impairment persists following recovery. Study of social cognition in AN may elucidate impaired processes that may influence therapeutic efficacy. Symptoms of autism spectrum disorders (ASD) are overrepresented in those who evidence a chronic course. Relative to that in AN, social information processing in ASD is well characterized and may inform systematic study in AN. This article (a) reviews impaired interpersonal processes in AN, (b) compares the phenotype of AN with that of ASD, (c) highlights deficits of social cognitive disturbance in ASD relative to AN, and (d) proposes a new framework to understand the interaction of individuals with AN with their social context.     

Seeing it differently: visual processing in autism

Several recent behavioral and neuroimaging studies have documented an impairment in face processing in individuals with Autism Spectrum Disorder (ASD). It remains unknown, however, what underlying mechanism gives rise to this face processing difficulty. One theory suggests that the difficulty derives from a pervasive problem in social interaction and/or motivation. An alternative view proposes that the face-processing problem is not entirely social in nature and that a visual perceptual impairment might also contribute. The focus of this review is on this latter, perceptual perspective, documenting the psychological and neural alterations that might account for the face processing impairment. The available evidence suggests that perceptual alterations are present in ASD, independent of social function.     

Effects of perceived mutual gaze and gender on face processing and recognition memory

Perceived gaze contact in seen faces may convey important social signals. We examined whether gaze perception affects face processing during two tasks: Online gender judgement, and later incidental recognition memory. Individual faces were presented with eyes directed either straight towards the viewer or away, while these faces were seen in either frontal or three-quarters view. Participants were slower to make gender judgements for faces with direct versus averted eye gaze, but this effect was particularly pronounced for faces with opposite gender to the observer, and seen in three-quarters view. During subsequent surprise recognition-memory testing, recognition was better for faces previously seen with direct than averted gaze, again especially for the opposite gender to the observer. The effect of direct gaze was stronger in both tasks when the head was seen in three-quarters rather than in frontal view, consistent with the greater salience of perceived eye contact for deviated faces. However, in the memory test, face recognition was also relatively enhanced for faces of opposite gender in front views when their gaze was averted rather than direct. Together, these results indicate that perceived eye contact can interact with facial processing during gender judgements and recognition memory, even when gaze direction is task-irrelevant, and particularly for faces of opposite gender to the observer (an influence which controls for stimulus factors when considering observers of both genders). These findings appear consistent with recent neuroimaging evidence that social facial cues can modulate visual processing in cortical regions involved in face processing and memory, presumably via interconnections with brain systems specialized for gaze perception and social monitoring.     

孤独症儿童的情绪共情能力及情绪表情注意方式

研究探讨了孤独症儿童的情绪共情能力及情绪表情注意方式的特点。各选取15名孤独症儿童以及作为对照组的智力障碍儿童和普通儿童各15名, 完成情绪共情实验, 同时使用生物反馈仪记录自主生理反应, 眼动仪记录眼动轨迹。结果发现孤独症儿童对情绪表情的自动模仿及感知能力显著低于智力障碍儿童与普通儿童; 对面孔的总注视时间、总注视点数均显著少于智力障碍儿童、普通儿童; 对眼部、嘴部的注视时间比及注视点数比均显著低于普通儿童; 对高兴和悲伤表情的注意较多而对恐惧则较少。这提示孤独症儿童的情绪共情能力不足、对情绪表情的注意方式异常。     

Eye-contact perception in schizophrenia: relationship with symptoms and socioemotional functioning

Accurately perceiving self-referential social signals, particularly eye contact, is critical to social adaptation. Schizophrenia is often accompanied by deficits in social cognition, but it is unclear whether this includes gaze discrimination deficits. This study investigated whether eye-contact perception is preserved or impaired and if it is related to symptoms and broader socioemotional functioning in schizophrenia. Twenty-six participants with schizophrenia (SCZ) and 23 healthy controls (HC) made eye-contact judgments for faces in varying gaze direction (from averted to direct in ten 10% increments), head orientation (forward, 30° averted), and emotion (neutral, fearful). Psychophysical analyses for forward faces showed that SCZ began endorsing eye contact with weaker eye-contact signal and their eye-contact perception was less of a dichotomous function, as compared with HC. SCZ were more likely than HC to endorse eye contact when gaze was ambiguous, and this overperception of eye contact was modulated by head orientation and emotion. Overperception of eye contact was associated with more severe negative symptoms. Decreased categorical gaze perception explained variance of socioemotional deficits in schizophrenia after taking basic neurocognition into consideration, suggesting the relationship was not solely due to a general deficit problem. These results were discussed in relation to the nature of categorical gaze perception and its significance to clinical and functional presentations of schizophrenia.