Attentional modulation of perceptual organisation in schizophrenia

Introduction. Previous studies indicated impaired perceptual organisation in schizophrenia. This study investigated lateral connection and attentional modulation in early visual cortex of schizophrenia patients.

Methods. Contrast threshold was measured for a central Gabor patch, flanked with orthogonal and collinear Gabor patches. In the attended condition, participants performed a concurrent vernier task by determining the spatial offset of the flankers.

Results. The controls (n=25) had lower contrast thresholds in the collinear condition than in the orthogonal condition, whereas the schizophrenia patients (n=43) did not benefit from the presence of collinear flankers. This deficit was not ameliorated by attentional modulation. Antipsychotic medication did not affect the performance.

Conclusions. These results suggest that lateral connections are impaired in early visual cortex of schizophrenia patients. This deficit cannot be restored by top-down attentional modulation of target-flanker interactions.     

Innate and learned perceptual abilities in the newborn infant

 From research carried out over the last few years, it has become apparent that the visual world of the newborn baby (0–7 days from birth) is highly organised. It is also clear that the newborn infant is an extremely competent learner. These themes are illustrated with respect to two areas of research, face perception and intermodal learning. Evidence is presented suggesting that the human face is ”special” in that newborns respond to them as faces, rather than merely collections of stimulus elements. Additional evidence is presented which demonstrates that newborns can form auditory-visual associations after only a short exposure to the stimulation. These lines of evidence suggest that innate capacities, or modules, facilitate and direct early learning in order to allow newborn infants to understand their newly encountered world.     

Effects of Ketamine on perceptual grouping in rats

Ketamine is a selective NMDA glutamate receptor antagonist that disrupts cognitive and behavioral function. Evidence exists that NMDA receptors play a role in lateral cortical connections, suggesting involvement in integrating information across the cortex. To investigate NMDA receptors' role in cortical integration at a perceptual level, psychophysical measures were made of perceptual grouping, which requires global analysis of neural representations of stimulus elements. Rats were trained to discriminate solid lines as well as patterns of dots that could be perceptually grouped into vertical or horizontal stripes. Psychophysical measures determined thresholds of perceptual grouping capacities. Rats receiving maximum subanesthetic doses of Ketamine discriminated solid patterns normally, but were impaired on dot pattern discrimination when greater demands were placed on perceptual grouping. These results demonstrate a selective disruption by Ketamine of visual discrimination that requires perceptual grouping of stimulus patterns. These results also provide evidence associating NMDA receptor-dependent neural mechanisms with context-dependent perceptual function.     

精神分裂症患者认知功能损伤的神经生物学基础和电生理表现

精神分裂症患者存在严重的认知功能损伤,认知功能损伤的重要神经生物学基础是患者脑内神经递质水平异常,这会导致患者出现异常神经元电活动,脑电图指标可以客观、定量反映神经递质导致的异常神经元电活动。本文主要对国内外精神分裂症患者认知功能损伤的神经生物学和电生理学等研究情况进行综述,回顾了认知功能损伤相关神经递质的生物学机制,梳理了与之相关的异常神经生物电指标,为精神分裂症的发病原理和辅助诊断提供相应参考。未来的研究应更多关注疾病的致病基因、神经影像学等生物学标记物,建立精神分裂症辅助诊断的指标体系。     

帕金森病患者视觉功能障碍的研究

目的：探讨帕金森病患者视觉认知功能的变化。方法：选择从2008.01到2013.01期间在昆明医科大学第一附属医院神经内科就诊的H-Y分期为1或2期的帕金森病患者120例,男性76例,女性44例。和同期在我院进行健康检查的健康对照组100名,男性60例,女性40例。对所有患者进行MoCA、汉密顿抑郁和焦虑量表评价,所有受试者均不存在痴呆（MoCA≥26分）,亦不处于焦虑、抑郁状态（HAMA≤14分,HAMD-17项≤16分）,并进行班德视觉完形测验（Bender Visual Gestalt Test）和视觉诱发电位（VEP）检测。结果：PD组VEP的P100潜伏期（115±11）较健康对照组（103±9）ms明显延长（P〈0.01）,P100波幅（6.3±3.0）较健康对照组（7.7±2.6）μV增宽（P〈0.05）。班德视觉完形测验PD组患者全球评分系统（Global Scoring System GSS）得分明显低于健康对照组,差异有统计学意义。结论：帕金森病患者在发病早期即存在不同程度的视觉功能障碍,对于此类患者,我们应该早期给予训练和指导,从而减缓患者认知功能障碍的发展和避免跌倒发作,提高患者的生活质量。     

Attachment state of mind and perceptual processing of emotional stimuli

This study aimed to investigate the relationship between attachment state of mind and perceptual processing of social and non-social, affective, and neutral material. A total of 57 young adults completed the Adult Attachment Interview (AAI) plus an experimental task in which their perceptual thresholds to different types of pictures were assessed. Significant correlations were found between the AAI dimensions and perceptual thresholds for social stimuli such as social interactions or human faces displaying emotional expressions. As expected, no relationships were found between the AAI and perception of neutral stimuli. The pattern of correlations was especially clear for the dismissing dimension. The results suggest that higher vigilance to social stimuli is related to dismissing attachment tendencies and, to a milder degree, to preoccupied tendencies.     

Neural substrates for visual perceptual grouping in humans

Two experiments investigated the neural mechanisms of Gestalt grouping by recording high-density event-related brain potentials (ERPs) during discrimination tasks. In Experiment 1, stimulus arrays contained luminance-defined local elements that were either evenly spaced or grouped into columns or rows based on either proximity or similarity of shape. Proximity grouping was indexed by a short-latency positivity (110-120 ms) over the medial occipital cortex and a subsequent right occipitoparietal negativity. Grouping by similarity was reflected only in a long-latency occipitotemporal negativity. In Experiment 2, proximity grouping was examined when local elements were defined by motion cues, and was again associated with a medial occipital positivity. However, the subsequent long-latency negativity was now enhanced over the left posterior areas. The implications of these results to the neural substrates subserving different grouping processes are discussed.     

Remediation of memory disorders in schizophrenia

BACKGROUND: Memory deficits are commonly experienced by patients with schizophrenia, often persist even after effective psychotropic treatment of psychotic symptoms and have been demonstrated to interfere with many aspects of successful psychiatric rehabilitation. Because of significant impact on functional outcome, effective remediation of cognitive deficits has been increasingly cited as an essential component of comprehensive treatment. Efforts to remediate memory deficits have met with circumscribed success, leaving uncertain whether schizophrenia patients can be taught, without experimental induction, independently to employ semantic encoding or a range of other mnemonic techniques. METHOD: We examined the feasibility of using memory and problem solving teaching techniques developed within educational psychology--techniques which promote intrinsic motivation and task engagement through contextualization and personalization of learning activities--to remediate memory deficits in a group of in-patients with chronic schizophrenia spectrum disorders. RESULTS: Although our memory remediation group significantly improved on the memory remediation task, they did not make greater gains on measures of immediate paragraph recall or list learning than the control groups. CONCLUSIONS: Targeted remediation of memory appears to yield task specific improvement but the gains do not generalize to other memory tasks. Subjects receiving memory remediation failed to independently activate mnemonic encoding strategies learned and used successfully within training tasks to other general measures of verbal learning and memory.     

认知负载状态下的精神分裂症患者脑电图特异性研究

认知功能损害是精神分裂症的三大原发症状之一,在疾病早期发现和高危人群风险预警等方面具有重要价值。为了研究精神分裂症患者在认知负载状态下的脑电图特异性,本试验收集17例精神分裂症患者和19例健康受试者的脑电信号作为对照,基于小波变换提取各频段信号,计算非线性动力学及脑功能网络属性等特征,并利用机器学习算法将两类人群进行自动分类分析。试验结果表明,两组受试者在认知负载状态下,Fp1和Fp2导联在α、β、θ、γ这4个频带的关联维数和样本熵的差异均具有统计学意义,提示大脑额叶功能损伤是精神分裂症认知功能损害的重要原因。进一步基于机器学习的自动分类分析结果表明,将非线性动力学与脑功能网络属性相结合作为分类器的输入特征,所得分类效果最优,其结果显示准确率为76.77%、敏感度为72.09%、特异性为80.36%。本研究结果表明,脑电信号的非线性动力学和脑功能网络属性等特征,或可作为精神分裂症早期筛查和辅助诊断的潜在生物标记物。     

The influence of facial expression at perceptual threshold on electrodermal activity and social comfort distance

Interpersonal distance, an essential component of social interaction, is modulated by the emotion conveyed by others and associated physiological response. However, in modern societies with overcrowded and hyperstimulating environments, we can only surreptitiously glimpse the faces of others in order to quickly make behavioral adjustments. How this impacts social interactions is not yet well understood. In the present study, we investigated this issue by testing whether facial expressions that are difficult to identify modify the physiological response (Electrodermal Activity, EDA) and subsequent judgment of interpersonal comfort distance. We recorded participants’ EDA while they provided comfort judgments to interpersonal distances with a Point-Light Walker (PLW). The PLW, with an emotionally neutral gait, moved toward and crossed participants at various distances after the latter were exposed to a negative (anger), positive (happiness) or neutral facial expression presented at the perceptual threshold. Bayesian analyses of the data revealed an increase versus decrease of interpersonal comfort distance with the PLW depending on the negative versus positive emotional valence of the facial expression. They also showed an increase in EDA when the approaching PLW violated interpersonal comfort distance after participants were exposed to an angry facial expression. These effects correlated with the subjective assessment of the arousal of facial expressions. Thus, previous exposure to barely visible facial expressions can alter the representation of social comfort space and the physiological response associated with a violation of interpersonal comfort distances, depending on the valence and arousal of the emotional social stimuli.     

Twin-family studies of perceptual speed ability

Perceptual speed tests exhibit consistent sex differences, and an X-linked dominant gene has been hypothesized to explain female superiority in the aptitude. To evaluate that hypothesis, two tests from the ETS battery were administered to like-sex twins of college age, adult monozygotic twins, and their spouses and children. Offspring of MZ twins are genetic half-siblings reared as cousins in separate households; comparisons of the half-fraternities and half-sororities of male and female twin parents provide a direct test of X linkage. Test scores were transformed within age bands, and the age-sex standardized scores were evaluated for genetic variance and X-linked transmission. The analysis documents substantial heritability in perceptual speed that is inconsistent with X linkage. Gender differences in the ability may reflect polygenic transmission, with differing thresholds arising from cultural stereotypy in sex-role training.This is publication No. 78-42 from the Department of Medical Genetics and was supported by a USPHS Training Grant (GM 1056) and by the Indiana University Human Genetics Center (GM 21054).     

The evoked potential as a measure of perceptual and semantic differences

This review discusses the information content of perceptual and semantic evoked potentials arising in humans as a result of instantaneous changes in nonverbal and verbal stimuli. The amplitudes of perceptual and semantic evoked potentials were found to correlate positively with subjects’ assessments of the differences between these stimuli. Multidimensional scaling matrixes of evoked potential amplitudes and subjective assessments of differences on pairwise substitution of stimuli showed that the actual colors and color names occupied a four-dimensional spherical color space and were encoded by excitation vectors of identical lengths. Color differences were equal to the absolute differences between their excitation vectors, while semantic differences in color names corresponded to the absolute difference vectors represented by long-term color memory traces. These data were reviewed in the framework of a spherical model of cognitive processes. __________ Translated from Zhurnal Vysshei Nervnoi Deyatel’nosti imeni I. P. Pavlova, Vol. 56, No. 2, pp. 165–174, March–April, 2006.     

认知康复综合训练改善苯丙胺类依赖者认知功能的随机对照试验

目的:评估认知康复综合训练对改善苯丙胺类兴奋剂(ATS)依赖者认知功能障碍的疗效。方法:在强制戒毒机构招募符合精神障碍诊断与统计手册第4版(DSM-IV)苯丙胺类兴奋剂依赖者,随机分为干预组(30例)和对照组(26例)。对照组仅接受常规教育,干预组除接受常规教育外还接受24周的认知康复综合训练,主要包括心理康复与躯体康复。采用中文版Cog State量表(CSB)在干预前(基线)及干预24周末评估两组受试者的认知功能。结果:两组干预前的CSB各维度得分无统计学差异。在24周末干预结束时,干预组在单卡学习任务[(0.06±0.12)vs.(-0.03±0.14),P0.05]、Tw o-Back任务[(0.12±0.15)vs.(0.01±0.19),P0.05]、连续配对学习任务[(-0.46±0.35)vs.(-0.15±0.49),P0.05]三个维度得分改善优于对照组。两组其余5个维度得分变化即检出任务、识别任务、国际购物清单任务、Groton迷宫任务、社会情绪识别任务无统计学差异(均P0.05)。结论:认知康复综合训练可以改善苯丙胺类依赖者的视觉学习记忆、工作记忆和空间工作记忆,而对其他方面认知功能无明显改善。     

Cognitive adaptation training for outpatients with schizophrenia

Schizophrenia is a complex neurodevelopmental disorder characterized by cognitive deficits. These deficits in cognitive functioning have been shown to relate to a variety of functional and treatment outcomes. Cognitive adaptation training (CAT) is a home‐based, manual‐driven treatment that utilizes environmental supports and compensatory strategies to bypass cognitive deficits and improve target behaviors and functional outcomes in individuals with schizophrenia. Unlike traditional case management, CAT provides environmental supports and compensatory strategies tailored to meet the behavioral style and neurocognitive deficits of each individual patient. The case of Ms. L. is presented to illustrate CAT treatment. © 2009 Wiley Periodicals, Inc. J Clin Psychol: In Session 65:1–12, 2009.     

The impact of cognitive training on spontaneous gamma oscillations in schizophrenia

Schizophrenia patients exhibit less gamma‐frequency EEG/MEG activity (>30 Hz), a finding interpreted as evidence of poor temporal neural organization and functional network communication. Research has shown that neuroplasticity‐oriented training can improve task‐related oscillatory dynamics, indicating some reorganization capacity in schizophrenia. Demonstrating a generalization of such task training effects to spontaneous oscillations at rest would not only enrich understanding of this neuroplastic potential but inform the interpretation of spontaneous gamma oscillations in the service of normal cognitive function. In the present study, neuromagnetic resting‐state oscillatory brain activity and cognitive performance were assessed before and after training in 61 schizophrenia patients, who were randomly assigned to 4 weeks of neuroplasticity‐oriented targeted cognitive training or treatment as usual (TAU). Gamma power of 40–90 Hz increased after training, but not after TAU, in a frontoparietal network. Across two types of training, this increase was related to improved cognitive test performance. These results indicate that abnormal oscillatory dynamics in schizophrenia patients manifested in spontaneous gamma activity can be changed with neuroplasticity‐oriented training parallel to cognitive performance.     

Specific cognitive abilities in 5- to 12-year-old twins

Eleven tests of specific cognitive abilities were administered to 108 pairs of young twins (average age of 7.6 years). Internal consistencies are high for all measures except Raven's Coloured Progressive Matrices and Delayed Picture Memory. Two-month, test-retest reliabilities are also reported. The twin sample is representative in terms of both means and variances when compared to normative data from standardization samples, and twin correlations for height and weight are similar to those obtained in six other twin studies. Because all measures were highly correlated with age (average correlation with age was 0.64), scores were age adjusted. Previous twin studies of specific cognitive abilities in adolescents and adults found genetic variance for nearly all tests. In contrast, our study of young twins yielded significant genetic influence for only 1 of the 11 measures, PIAT Reading Recognition, and suggested the possibility of genetic influence on 2 others (vocabulary and WISC-R mazes). Environmental influences seem to dominate, particularly for nonverbal measures, as children begin their education. In accord with other studies, we found that between-family environmental factors have an important influence on the development of nearly all of the measures of specific cognitive abilities. However, we found that our tests of perceptual speed and memory were substantially influenced by within-family environmental factors independent of error.This work was supported by a grant from the Spencer Foundation.     

Subjective figure reversal in two- and three-dimensional perceptual space

A permanently illuminated pattern of Mach's truncated pyramid can be perceived according to the experimental instruction given, either as a three-dimensional reversible figure with spontaneously changing convex and concave interpretation (in one experiment), or as a two-dimensional reversible figure-ground pattern (in another experiment). The reversal rate was about twice as slow, without the subjects being aware of it, if it was perceived as a three-dimensional figure compared to the situation when it was perceived as two-dimensional. It may be hypothetized that in the three-dimensional case, the process of perception requires more sequential steps than in the two-dimensional one.     

Twin-family studies of perceptual speed ability. II. Parameter estimation

Offspring of monozygotic (MZ) twins form half-sibships that permit a direct test of maternal effects and differentiate several sources of between-family environmental variance. Combined with conventional twin data, these genetic half-sibships provide a unique data set for estimating sources of variation in quantitative traits. To illustrate, genetic and environmental parameters were estimated for Identical Pictures Test data obtained from children of MZ twin parents and an (approximate) agematched cohort of like-sex twins. Analyses of variance of the data, standardized for age and sex, yield 12 mean squares to which gene-environment models were fit. Maximum-likelihood estimation revealed a complete absence of maternal influences and shared environmental effects; a simple two-parameter model, assuming random mating and attributing variation in test scores to additive genes and within-family environment, adequately accounts for the familial data.This work was supported by the Indiana University Human Genetics Center (GM 21054), a faculty grant-in-aid to RJR, and a postdoctoral fellowship (HL 5863) to JZM; ascertainment and genotyping of twins were supported, in part, by the Specialized Center of Research (SCOR) in Hypertension (HL 14159) and by a grant (HL 20034) from the High Blood Pressure in the Young Program. Portions of this paper were presented by the first author at the Third International Congress on Twin Studies, Jerusalem, 1980.