孤独症谱系障碍者视觉定向与视觉搜索的特点及神经机制

定向网络是注意网络的重要组成部分, 主要包括视觉定向与视觉搜索两大任务。对于这两大注意任务, 正常个体在神经机制上存在较大的重叠, 然而, 孤独症个体却表现出截然相反的行为证据。研究者从非社会信息的注意视角发现, 一般而言, 在视觉定向上, 孤独症个体注意转移不存在缺陷, 而注意脱离存在困难, 但该结论仍有争议; 在视觉搜索上, 孤独症个体存在视觉搜索优势, 但该优势发生的阶段及原因仍需进一步探究。未来研究应进一步考察孤独症个体在视觉定向任务中左右视野的不对称性、视觉搜索优势的内在机制及两大注意任务之间的相互关系。     

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。     

ERP evidence for task modulations on face perceptual processing at different spatial scales

Does the perceptual processing of faces flexibly adapt to the requirements of the categorization task at hand, or does it operate independently of this cognitive context? Behavioral studies have shown that the fine and coarse spatial scales of a face are differentially processed depending on the categorization task performed, thus suggesting that the latter can influence stimulus perception. Here, we investigated the time course of these task influences on perceptual processing by examining the visual N170 face‐sensitive Event‐Related Potential (ERP), while observers categorized faces for their gender and familiarity. Stimuli were full spectrum, or filtered versions that preserved either coarse or fine scale information of the faces. Behavioral results replicated previous findings of a differential processing of coarse and fine spatial scales across tasks. In addition, the N170 amplitude was larger in the Gender task as compared to the Familiarity task for LSF faces exclusively, thus showing that task demands differentially modulated the spatial scale processing on faces. These results suggest that the diagnosticity of scale‐specific cues in categorization tasks can modulate face processing.     

Reduced interhemispheric interaction in non-autistic individuals with normal but high levels of autism traits

People with autism spectrum disorder (ASD) show superior performance for tasks requiring detail-focused processing. Atypical neural connectivity and reduced interhemispheric communication are posited to underlie this cognitive advantage. Given recent conceptualization of autism as a continuum, we sought to investigate whether people with normal but high levels of autism like traits (AQ) also exhibit reduced hemispheric interaction. Sixty right-handed participants completed the AQ questionnaire (Baron-Cohen, Wheelwright, Skinner, Martin, & Clubley, 2001) and a lateralised letter matching task that assessed unilateral and bilateral performance in response to simple (physical) and complex (identity) matches. Whereas people with low self-rated AQ scores showed a bilateral advantage for the more complex task, indicating normal interhemispheric interaction, people in the high AQ group failed to show a bilateral gain for the computationally demanding stimuli. This finding of disrupted interhemispheric interaction converges with a dimensional conceptualisation of ASD, suggesting that the structural anomalies of ASD extend to non-autistic individuals with high levels of autism traits.     

Mr. Grimace or Ms. Smile: does categorization affect perceptual processing in autism?

This study compared the influence of categorization on perceptual processing in adults with autistic spectrum disorders (ASD) and normal control participants. Participants were asked to categorize hybrid faces (composed of two overlapped faces of different spatial bandwidths) by gender and emotion. Control participants exhibited a bias for low-pass information during gender categorization and a bias for high-pass information during emotion categorization. By contrast, adults with ASD showed the same low-pass bias in both tasks. This absence of a shift in processing style in the ASD group is discussed in terms of diminished top-down modulation in autism.     

Facial Emotion Recognition in Autism Spectrum Disorders: A Review of Behavioral and Neuroimaging Studies

Behavioral studies of facial emotion recognition (FER) in autism spectrum disorders (ASD) have yielded mixed results. Here we address demographic and experiment-related factors that may account for these inconsistent findings. We also discuss the possibility that compensatory mechanisms might enable some individuals with ASD to perform well on certain types of FER tasks in spite of atypical processing of the stimuli, and difficulties with real-life emotion recognition. Evidence for such mechanisms comes in part from eye-tracking, electrophysiological, and brain imaging studies, which often show abnormal eye gaze patterns, delayed event-related-potential components in response to face stimuli, and anomalous activity in emotion-processing circuitry in ASD, in spite of intact behavioral performance during FER tasks. We suggest that future studies of FER in ASD: 1) incorporate longitudinal (or cross-sectional) designs to examine the developmental trajectory of (or age-related changes in) FER in ASD and 2) employ behavioral and brain imaging paradigms that can identify and characterize compensatory mechanisms or atypical processing styles in these individuals.     

Hemispheric processing of idioms in schizophrenia and autism spectrum disorder

Studies conducted on individuals with schizophrenia (SZ) and autism spectrum disorder (ASD) show that they find it difficult to comprehend figurative language, and have a tendency to interpret it literally. This study examines hemispheric processing of idioms in patients with SZ, in comparison to individuals with ASD. Seventeen adults with SZ and 18 adults with ASD participated in the study. The two clinical groups were matched in age, vocabulary scores and verbal executive function scores. Using the divided visual field paradigm, the participants performed a lexical decision task for a target word related to either a literal or a figurative interpretation of an idiom. Whereas SZ patients showed the typical right lateralisation for non-salient literal interpretations of idioms, adults with ASD showed atypical bilateral processing. These findings indicate different hemispheric lateralisation in idiom processing in the two clinical groups.     

Lexical effects on speech perception in individuals with "autistic" traits

It has been claimed that Autism Spectrum Disorder (ASD) is characterized by a limited ability to process perceptual stimuli in reference to the contextual information of the percept. Such a connection between a nonholistic processing style and behavioral traits associated with ASD is thought to exist also within the neurotypical population albeit in a more subtle way. We examined this hypothesis with respect to auditory speech perception, by testing whether the extent to which phonetic categorization shifts to make the percept a known word (i.e., the 'Ganong effect') is weakened as a function of autistic traits in neurotypicals. Fifty-five university students were given the Autism-Spectrum Quotient (AQ) and a segment identification test using two word-to-nonword Voice Onset Time (VOT) continua (kiss-giss and gift-kift). A significant negative correlation was found between the total AQ score and the identification shift that occurred between the continua. The AQ score did not correlate with scores on separately administered VOT discrimination, auditory lexical decision, or verbal IQ, thus ruling out enhanced auditory sensitivity, slower lexical access or verbal intelligence as explanations of the AQ-related shift in phonetic categorization.     

Facial expression coding in children and adolescents with autism: Reduced adaptability but intact norm-based coding

Individuals with autism spectrum disorder (ASD) can have difficulty recognizing emotional expressions. Here, we asked whether the underlying perceptual coding of expression is disrupted. Typical individuals code expression relative to a perceptual (average) norm that is continuously updated by experience. This adaptability of face-coding mechanisms has been linked to performance on various face tasks. We used an adaptation aftereffect paradigm to characterize expression coding in children and adolescents with autism. We asked whether face expression coding is less adaptable in autism and whether there is any fundamental disruption of norm-based coding. If expression coding is norm-based, then the face aftereffects should increase with adaptor expression strength (distance from the average expression). We observed this pattern in both autistic and typically developing participants, suggesting that norm-based coding is fundamentally intact in autism. Critically, however, expression aftereffects were reduced in the autism group, indicating that expression-coding mechanisms are less readily tuned by experience. Reduced adaptability has also been reported for coding of face identity and gaze direction. Thus, there appears to be a pervasive lack of adaptability in face-coding mechanisms in autism, which could contribute to face processing and broader social difficulties in the disorder.     

注意线索对自闭特质个体疼痛共情的影响：来自事件相关电位的证据

自闭特质个体在日常生活中表现出共情缺损, 但其程度较自闭症谱系障碍个体低, 并且注意线索和特异性的面孔加工可能会影响他们的共情加工进程。因此, 本研究采用事件相关电位(ERP)技术, 以疼痛面孔图片作为刺激材料, 让自闭特质组和控制组分别完成疼痛判断任务(该任务中被试的注意指向疼痛线索)和吸引力判断任务(该任务中被试的注意不指向疼痛线索)。结果发现, 相比控制组, 自闭特质组在吸引力判断任务中疼痛面孔图片诱发的P3波幅更大, 而在疼痛判断任务中两组没有显著差异。这表明注意线索会影响自闭特质个体对他人疼痛面孔的共情反应, 当自闭特质个体不注意他人面孔的疼痛线索时, 其疼痛共情能力会减弱。     

Patients with chronic fatigue syndrome do not score higher on the autism‐spectrum quotient than healthy controls: Comparison with autism spectrum disorder

Clinically, there is an overlap of several symptoms of chronic fatigue syndrome (CFS ) and autism spectrum disorder (ASD ), including fatigue; brain “fog”; cognitive impairments; increased sensitivity to sound, light, and odour; increased pain and tenderness; and impaired emotional contact. Adults with CFS (n = 59) or ASD (n = 50) and healthy controls (HC ; n = 53) were assessed with the Autism‐Spectrum Quotient (AQ ) in a cross‐sectional study. Non‐parametric analysis was used to compare AQ scores among the groups. Univariate analysis of variance (ANCOVA ) was used to identify if age, sex, or diagnostic group influenced the differences in scores. Patients with ASD scored significantly higher on the AQ than the CFS group and the HC group. No differences in AQ scores were found between the CFS and HC groups. AQ results were influenced by the diagnostic group but not by age or sex, according to ANCOVA . Despite clinical observations of symptom overlap between ASD and CFS , adult patients with CFS report few autistic traits in the self‐report instrument, the AQ . The choice of instrument to assess autistic traits may influence the results.     

Low-level visual attention and its relation to joint attention in autism spectrum disorder

Visual attention is integral to social interaction and is a critical building block for development in other domains (e.g., language). Furthermore, atypical attention (especially joint attention) is one of the earliest markers of autism spectrum disorder (ASD). The current study assesses low-level visual attention and its relation to social attentional processing in youth with ASD and typically developing (TD) youth, aged 7 to 18 years. The findings indicate difficulty overriding incorrect attentional cues in ASD, particularly with non-social (arrow) cues relative to social (face) cues. The findings also show reduced competition in ASD from cues that remain on-screen. Furthermore, social attention, autism severity, and age were all predictors of competing cue processing. The results suggest that individuals with ASD may be biased towards speeded rather than accurate responding, and further, that reduced engagement with visual information may impede responses to visual attentional cues. Once attention is engaged, individuals with ASD appear to interpret directional cues as meaningful. These findings from a controlled, experimental paradigm were mirrored in results from an ecologically valid measure of social attention. Attentional difficulties may be exacerbated during the complex and dynamic experience of actual social interaction. Implications for intervention are discussed.     

背景性质对7-10岁自闭症谱系障碍儿童面孔搜索与加工的作用

为了考察背景性质对ASD者搜索面孔的影响,设计两个眼动实验任务,要求14名7~10岁ASD儿童和20名同年龄正常儿童观看图片。实验一采用将面孔嵌入风景图片中引起语义不一致的刺激;实验二采用含有面孔的无意义背景乱序图片刺激。结果发现：（1）面孔与背景语义不一致并不能促进ASD儿童对面孔的搜索;（2）乱序背景对ASD儿童面孔搜索与加工没有产生干扰作用,但使正常儿童的搜索时间变长;（3）一旦觉察到面孔后,ASD儿童对面孔的注视时间少于正常儿童。表明正常儿童对面孔的搜索与加工受背景性质的影响,而ASD儿童不受背景性质的影响;一旦发现面孔,ASD儿童的注意维持较短,但面孔加工模式与正常儿童相似。     

自闭症谱系障碍儿童对面孔加工的同龄偏向效应

采用视觉追踪技术,探讨自闭症谱系障碍(autism spectrum disorders, ASD)儿童面孔加工的同龄偏向效应。实验1选取19名ASD儿童和23名生理年龄匹配的普通儿童(typically developing, TD)为被试,通过自由观看同龄和异龄中性面孔,探讨ASD儿童是否存在面孔加工的同龄偏向效应;实验2选取22名ASD儿童和生理年龄匹配的25名TD儿童,通过自由观看快乐、愤怒和恐惧面孔,探讨情绪对ASD儿童面孔加工同龄偏向的影响。结果发现,(1)ASD儿童对同龄中性面孔的注视时间显著大于异龄中性面孔;(2)ASD儿童在愤怒和恐惧情绪下对同龄面孔的注视时间显著大于异龄面孔,而在快乐情绪下同龄和异龄的注视时间则无显著差异。这表明ASD儿童对面孔的注视加工存在同龄偏向效应,且受情绪的影响。     

Perceptual learning and perceptual search are altered in male university students with higher Autism Quotient scores

Two experiments investigated the validity of the Autism Quotient (AQ) scale for measuring traits associated with Autism Spectrum Disorders (ASD) in a population of male university students. Both studies found evidence that individuals who scored higher on the AQ questionnaire performed in a similar way to individuals with ASD on tasks with a perceptual component. Experiment 1 demonstrated a difference in the degree to which higher scoring AQ individuals performed on a perceptual learning task; with higher AQ scorers showing no advantage for familiar over novel items less. In Experiment 2, higher scorers showed fewer errors when judging the elements, as opposed to the global configuration, of a Navon task letter. Both of these patterns of results had previously been noted in individuals with ASD. These results suggest that the AQ may have some validity in identifying individuals in the nonclinical population with similar performance profiles to those with ASD.     

视觉正常的自闭症儿童双眼注视点间距的特点及其意义

视网膜上物象对应的外在注视点之间的距离, 即双眼注视点间距(distance of binoculars point of regard, DBPR)在自闭症谱系障碍(autism spectrum disorders, ASD)个体上存在异常的表现, 而ASD个体伴随较高的斜视发病率, 可能会对其双眼注视点间距产生影响。研究采用正弦曲线平滑追踪任务范式, 探索视觉正常的ASD儿童在动态刺激加工过程中DBPR的鉴别意义。结果发现, ASD儿童DBPR过大且具有跨任务类型的稳定性, 且与斜视无关。DBPR在大振幅、快速度的条件下具有优良的鉴别力, 并与自闭症行为量表总分以及感知觉维度显著正相关。结果表明, 双眼注视点间距具有良好的鉴别价值。     

Face engagement during infancy predicts later face recognition ability in younger siblings of children with autism

Face recognition difficulties are frequently documented in children with autism spectrum disorders (ASD). It has been hypothesized that these difficulties result from a reduced interest in faces early in life, leading to decreased cortical specialization and atypical development of the neural circuitry for face processing. However, a recent study by our lab demonstrated that infants at increased familial risk for ASD, irrespective of their diagnostic status at 3 years, exhibit a clear orienting response to faces. The present study was conducted as a follow‐up on the same cohort to investigate how measures of early engagement with faces relate to face‐processing abilities later in life. We also investigated whether face recognition difficulties are specifically related to an ASD diagnosis, or whether they are present at a higher rate in all those at familial risk. At 3 years we found a reduced ability to recognize unfamiliar faces in the high‐risk group that was not specific to those children who received an ASD diagnosis, consistent with face recognition difficulties being an endophenotype of the disorder. Furthermore, we found that longer looking at faces at 7 months was associated with poorer performance on the face recognition task at 3 years in the high‐risk group. These findings suggest that longer looking at faces in infants at risk for ASD might reflect early face‐processing difficulties and predicts difficulties with recognizing faces later in life.     

Deeper attentional masking by lateral objects in children with autism

Autism spectrum disorder (ASD) is often associated with a detail-oriented perception and overselective attention in visual tasks, such as visual search and crowding. These results were obtained manipulating exclusively the spatial properties of the stimuli: few is known about the spatio-temporal dynamics of visual processing in ASD. In this study we employed an attentional masking (AM) paradigm comparing children with ASD and IQ-matched typically developing (TD) controls. The AM effect refers to an impaired identification of a target followed by a competitive masking object at different proximities in space and time. We found that ASD and TD groups did not differ in the AM effect provoked by the competitive object displayed in the same position of the target. In contrast, children with ASD showed a deeper and prolonged interference than the TD group when the masking object was displayed in the lateral position. These psychophysical results suggest that the inefficient attentional selection in ASD depends on the spatio-temporal interaction between competitive visual objects. These evidence are discussed in the light of the ASD altered neural connectivity hypothesis and the reentrant theory of perception.     

任务难度对自闭症儿童视觉搜索优势显现的影响

探究自闭症谱系障碍(ASD)儿童视觉搜索优势的显现是否受任务难度影响及优势存在机理。本研究采集ASD和正常发育(TD)儿童完成不同难度等级视觉搜索任务的行为和眼动数据。结果发现：在高难度等级任务中ASD组的准确率显著高于TD组;ASD组在任务中对目标刺激的回视次数、对靶子和外周感兴趣区的注视时间显著少于TD组,且ASD组偏好注视刺激的右侧区域。结果表明ASD儿童视觉搜索优势显现受任务难度影响,且可能与其对干扰刺激增强的知觉能力有关。     

Effects of spatial frequency content on classification of face gender and expression

The role of different spatial frequency bands on face gender and expression categorization was studied in three experiments. Accuracy and reaction time were measured for unfiltered, low-pass (cut-off frequency of 1 cycle/deg) and high-pass (cutoff frequency of 3 cycles/deg) filtered faces. Filtered and unfiltered faces were equated in root-mean-squared contrast. For low-pass filtered faces reaction times were higher than unfiltered and high-pass filtered faces in both categorization tasks. In the expression task, these results were obtained with expressive faces presented in isolation (Experiment 1) and also with neutral-expressive dynamic sequences where each expressive face was preceded by a briefly presented neutral version of the same face (Experiment 2). For high-pass filtered faces different effects were observed on gender and expression categorization. While both speed and accuracy of gender categorization were reduced comparing to unfiltered faces, the efficiency of expression classification remained similar. Finally, we found no differences between expressive and non expressive faces in the effects of spatial frequency filtering on gender categorization (Experiment 3). These results show a common role of information from the high spatial frequency band in the categorization of face gender and expression.