Down syndrome: cognitive phenotype

Down syndrome is the most prevalent cause of intellectual impairment associated with a genetic anomaly, in this case, trisomy of chromosome 21. It affects both physical and cognitive development and produces a characteristic phenotype, although affected individuals vary considerably with respect to severity of specific impairments. Studies focusing on the cognitive characteristics of Down syndrome were reviewed, and while performance in most areas could be predicted based upon overall intellectual disability, relative weaknesses were consistently found to be associated with expressive language, syntactic/morphosyntactic processing, and verbal working memory. This profile of uneven deficits could result from a failure to develop typically automatic processing for speech perception and production, and this possibility is discussed along with its implications for intervention.     

体型知觉的准确性及其认知机制

体型知觉的准确性既和一般人群的心理健康水平有关,又对进食障碍的理解、预防和治疗具有重要意义。首先,进食障碍患者可能高估自己的身体,其体型知觉准确度可能受其BMI和症状的影响,并与患者预后相关。其次,通过和对他人体型估计的结果进行对比发现,对自己的体型的高估可能受到对自己身体态度因素的影响。第三,一般人群对自己的体型估计的结果往往不一致,这可能是体型知觉的不同量化方式所致。最后,体型知觉准确性的相关认知机制主要有收缩偏差、视觉适应和序列依赖效应。     

Adaptive regression and types of cognitive flexibility

The relationship between adaptive regression and cognitive flexibility was explored in a group of 42 college students. Adaptive regression was measured with the Holt scoring system for the Rorschach. One type of cognitive flexibility was measured by Guilford's tests of divergent production (Word Fluency, Associational Fluency, and Alternate Uses) and a second type by Mednick's Remote Associates Test. Adaptive regression was found to be significantly positively related to the Remote Associates Test in males but not in females. Adaptive regression was found to be unrelated to divergent production tests. These relationships were not found to be mediated by Rorschach productivity or verbal intelligence. A two-stage process was proposed to account for the cognitive operations underlying adaptive regression and the Remote Associates Test. The first stage is seen as a generative (primary process) stage, while the second stage is seen as an evaluative (secondary process) stage. Possible reasons for sex differences were also discussed.     

Developmental cognitive neuroscience: progress and potential

Developmental cognitive neuroscience is an evolving field that investigates the relations between neural and cognitive development. Lying at the intersection of diverse disciplines, work in this area promises to shed light on classic developmental questions, mechanisms subserving developmental change, diagnosis and treatment of developmental disorders, and cognitive and neuroscientific topics traditionally considered outside the domain of development. Fundamental questions include: What are the interrelations between developmental changes in the brain (e.g. in connectivity, chemistry, morphology) and developmental changes in children's behavior and cognitive abilities (e.g. representational complexity, ability to sustain selective attention, speed of processing)? Why, and how, is learning enhanced during certain periods in development? How is our knowledge organized, and how does this change with development? We discuss preliminary investigations of such questions and directions for future work.     

Hand laterality and cognitive ability: a multiple regression approach

Several different associations between hand laterality and cognitive ability have been proposed. Studies reporting different conclusions vary in their procedures for defining laterality, and several of them rely on measures which are statistically problematic. Previous methods for measuring relative hand skill have not satisfactorily separated the overall level of hand skill, which is a known correlate of cognitive ability, from the asymmetry of its distribution. This paper uses a multiple regression paradigm that separates these two components. Support is found for Leask and Crow's [Trends in Cognitive Sciences, 5 (2001) 513] proposal that average cognitive ability increases monotonically with increasing strength of laterality, regardless of its direction. The small average advantage to dextrals stems from them being more strongly lateralised than sinistrals. The paucity of strong dextrals amongst the very gifted is due to a smaller variance in cognitive ability in this group.     

Interpret with caution: multicollinearity in multiple regression of cognitive data

Shibihara and Kondo in 2002 reported a reanalysis of the 1997 Kanji picture-naming data of Yamazaki, Ellis, Morrison, and Lambon-Ralph in which independent variables were highly correlated. Their addition of the variable visual familiarity altered the previously reported pattern of results, indicating that visual familiarity, but not age of acquisition, was important in predicting Kanji naming speed. The present paper argues that caution should be taken when drawing conclusions from multiple regression analyses in which the independent variables are so highly correlated, as such multicollinearity can lead to unreliable output.     

提取引起的遗忘的认知机制

提取引起的遗忘(RIF)指提取某个信息导致对其它相关信息的遗忘,揭示其内在机制是记忆和遗忘领域的一个重要的研究课题。近20年来,各路研究者分别从干扰理论、抑制理论或情境依赖说出发,试图找到引发RIF的唯一的认知机制。基于对有关RIF的认知机制的实证研究的系统分析,可以发现三个理论均有一定的支持证据,因此导致RIF的原因可能包括抑制、干扰和情境的改变等三个方面。今后该领域可结合多种技术手段对这一多元论观点进行直接的检验。     

Judgments of risk frequencies: tests of possible cognitive mechanisms

How do people judge which of 2 risks claims more lives per year? The authors specified 4 candidate mechanisms and tested them against people's judgments in 3 risk environments. Two mechanisms, availability by recall and regressed frequency, conformed best to people's choices. The same mechanisms also accounted well for the mapping accuracy of estimates of absolute risk frequencies. Their nearly indistinguishable level of performance is remarkable given their different assumptions about the underlying cognitive processes and the fact that they give rise to different expectations regarding the accuracy of people's inferences. The authors discuss this seeming paradox, the lack of impact of financial incentives on judgmental accuracy, and the dominant interpretation of inaccurate inferences in terms of biased information processing.     

Social interaction and cognitive growth: Possible causal mechanisms

The causal role of social interaction in the promotion of cognitive development has recently emerged as an important issue in developmental psychology. Two dominant theoretical orientations are currently guiding the empirical studies. The Piagetian perspective has influenced studies conducted to measure operational advances in cognitive functioning as a result of conflict between children. Vygotsky's developmental framework has provoked interest in the ontogenesis of self-regulatory abilities in children through an analysis of social problem solving. Both seek to explain cognitive development through social processes. Theoretical and empirical links between the two approaches are explored, and the possible role of linguistic processes as causal mechanisms examined.     

Attachment and cognitive skills: An investigation of mediating mechanisms

Associations between maternal attachment patterns and cognitive skills at first grade were examined, and mediators of identified associations tested using Phase I and II data from the National Institute of Child Health and Human Development Study of Early Care and Youth Development, a prospective study of 1364 children and families from birth through sixth grade. There were three main findings. First, ambivalent and insecure/other attachment patterns were negative predictors of cognitive skills. Second, the association between ambivalent attachment and cognitive skills was mediated by children's behaviors related to testing. Third, the association between insecure/other attachment and cognitive skills was mediated by children's exploration, maternal instruction, children's social relationships, and children's behaviors related to testing. Implications for attachment theory and education are discussed.     

Clinical, electroencephalographic and computer tomographic studies of children with West and Lennox-Gastaut syndrome

The results of clinical, electroencephalographic and repeated computed tomographic examination of 14 children suffering from epileptic seizures in connection with the West and Lennox-Gastaud syndrome are analyzed and compared. Computed tomography yields little information regarding the etiology of such forms of epilepsy. Distinct clinical and electroencephalographic findings were accompanied by normal computed tomographic results in a large proportion of the cases. To avoid misinterpretation of computed tomographic findings and consequent prognostic errors in these epileptic cases it is necessary to take possible side effects of ACTH and corticosteroid treatment into account. At the climax of hormone treatment computed tomography revealed imposing changes in the form of generalized atrophy in 10 of the 14 children examined. These receded completely upon termination of hormone treatment.     

The dual-task practice advantage: Empirical evidence and cognitive mechanisms

Practice of two simultaneous component tasks in dual-task situations leads to an improvement in dual-task performance. The present paper reviews empirical evidence for this practice-related improvement and discusses its underlying cognitive mechanisms. In particular, the robustness of the phenomenon of dual-task practice advantage (DTPA) is evaluated. This phenomenon is described as an advantage in dual-task performance at the end of dual-task practice (i.e., simultaneous task practice) in comparison to the dual-task performance after single-task practice (i.e., separate task practice). The review investigates the existence of empirical evidence of the DTPA phenomenon and specifications of its mechanisms in the context of the allocation and scheduling hypothesis and the integration hypothesis. Evidence for the existence of the DTPA phenomenon and the allocation and scheduling hypothesis was demonstrated in dual tasks with (1) combinations of two sensorimotor tasks, (2) combinations of one continuous task and one sensorimotor task, (3) combinations of two working-memory tasks, and (4) combinations of one motor task and one cognitive task. In contrast, the findings demonstrate that the DTPA phenomenon in dual tasks with (5) combinations of two long-term memory retrieval tasks can instead be explained by the integration hypothesis. The relevance of these findings is discussed in relation to real-world problems.

     

The variable nature of cognitive control: a dual mechanisms framework

A core component of cognitive control - the ability to regulate thoughts and actions in accordance with internally represented behavioral goals - might be its intrinsic variability. In this article, I describe the dual mechanisms of control (DMC) framework, which postulates that this variability might arise from qualitative distinctions in temporal dynamics between proactive and reactive modes of control. Proactive control reflects the sustained and anticipatory maintenance of goal-relevant information within lateral prefrontal cortex (PFC) to enable optimal cognitive performance, whereas reactive control reflects transient stimulus-driven goal reactivation that recruits lateral PFC (plus a wider brain network) based on interference demands or episodic associations. I summarize recent research that demonstrates how the DMC framework provides a coherent explanation of three sources of cognitive control variation - intra-individual, inter-individual and between-groups - in terms of proactive versus reactive control biases.     

Vagus nerve stimulation and Lennox-Gastaut syndrome: a review of the literature and data from the VNS patient registry

Lennox-Gastaut syndrome (LGS) is a severe form of childhood epilepsy that is usually refractory to medical management. When medication fails, alternative therapies are considered. Among these are two surgical options: corpus callosotomy and vagus nerve stimulation (VNS). Safety and efficacy are two important factor to consider when selecting an appropriate treatment. VNS is safer than callosotomy, but its efficacy is more difficult to assess. Available studies evaluate its effectiveness using a mixed population of patients (some with prior epilepsy surgery), a multitude of VNS settings, and variable endpoints. To estimate the efficacy of VNS in patients with LGS, a review of the medical literature and the VNS Patient Registry was performed. Within the limits of this type of study, the results showed that VNS appears to be equally as effective as callosotomy. Because VNS has a lower potential for adverse effects, these results suggest that VNS should be considered first in appropriately selected patients.     

绝对音高加工的认知神经机制

绝对音高(absolute pitch,AP)是一种比较罕见的音高加工能力,具有特殊的认知和神经机制。事件相关电位研究表明AP音乐家进行音高命名时,工作记忆参与较少但涉及多个认知策略。功能神经成像研究发现左侧额叶背侧后部和左侧颞叶平面对AP音乐家非常重要,而准AP音乐家(quasi-AP)的某些右侧脑区的参与则反映其增加的音高加工负荷和难度。结构神经成像研究发现AP音乐家具有特殊的灰质结构形态及白质连接。未来研究有待将AP能力进一步分为"具有相对音高能力"与"没有相对音高能力"两类并观察相应的认知神经机制,并通过影像基因组学来探索基因多态性对AP能力的影响,以及有必要观察以声调语言为母语的音乐家进行音高加工的神经机制。