The pars triangularis in dyslexia and ADHD: A comprehensive approach

Limited research has been conducted on the structure of the pars triangularis (PT) in dyslexia despite functional neuroimaging research finding it may play a role in phonological processing. Furthermore, research to date has not examined PT size in ADHD even though the right inferior frontal region has been implicated in the disorder. Hence, one of the purposes of this study was to examine the structure of the PT in dyslexia and ADHD. The other purposes included examining the PT in relation to overall expressive language ability and in relation to several specific linguistic functions given language functioning often is affected in both dyslexia and ADHD. Participants included 50 children: 10 with dyslexia, 15 with comorbid dyslexia/ADHD, 15 with ADHD, and 10 controls. Using a 2 (dyslexia or not) × 2 (ADHD or not) MANCOVA, findings revealed PT length and shape were comparable between those with and without dyslexia. However, children with ADHD had smaller right PT lengths than those without ADHD, and right anterior ascending ramus length was related to attention problems in the total sample. In terms of linguistic functioning, presence of an extra sulcus in the left PT was related to poor expressive language ability. In those with adequate expressive language functioning, left PT length was related to phonological awareness, phonological short-term memory and rapid automatic naming (RAN). Right PT length was related to RAN and semantic processing. Further work on PT morphology in relation to ADHD and linguistic functioning is warranted.     

Developmental shifts in fMRI activations during visuospatial relational reasoning

To investigate maturational plasticity of fluid cognition systems, functional brain imaging was undertaken in healthy 8-19 year old participants while completing visuospatial relational reasoning problems similar to Raven's matrices and current elementary grade math textbooks. Analyses revealed that visuospatial relational reasoning across this developmental age range recruited activations in the superior parietal cortices most prominently, the dorsolateral prefrontal, occipital-temporal, and premotor/supplementary cortices, the basal ganglia, and insula. There were comparable activity volumes in left and right hemispheres for nearly all of these regions. Regression analyses indicated increasing activity predominantly in the superior parietal lobes with developmental age. In contrast, multiple anterior neural systems showed significantly less activity with age, including dorsolateral and ventrolateral prefrontal, paracentral, and insula cortices bilaterally, basal ganglia, and particularly large clusters in the midline anterior cingulate/medial frontal cortex, left middle cingulate/supplementary motor cortex, left insula-putamen, and left caudate. Findings suggest that neuromaturational changes associated with visuospatial relational reasoning shift from a more widespread fronto-cingulate-striatal pattern in childhood to predominant parieto-frontal activation pattern in late adolescence.     

工作记忆负载对位置干扰子激活加工和抑制加工的影响

针对工作记忆（WM）负载对干扰子加工的影响存在认知控制机制和负载特异机制两种分歧观点的争议及Park等人的负载特异机制研究中存在的不足,文章尝试采用干扰效应和负启动效应双指标考察了三种不同类型的WM负载对位置干扰子加工的影响。结果表明,WM负载对位置干扰子加工的影响存在双重作用机制（认知控制机制和负载特异机制）;目标刺激与干扰子刺激的属性一致时,亦可得出负载特异机制观点,且可将WM任务与选择性注意任务之间竞争的资源锁定为知觉处理资源;导致上述两种观点争议的原因是以往研究未将干扰子加工过程分离为激活加工阶段和抑制加工阶段来考察;用双指标分离干扰子加工阶段的研究思路和方法不但可解决这两种观点的争议且可为两者的统合奠定基础。     

边界促进空间导航的认知神经机制

边界是指在人的视野中占据较大比例,且具有立体拓展平面的障碍物,对于人类和动物的空间导航行为具有极大的促进作用。认知发展研究发现儿童早期(1岁半～2岁)通过加工边界的空间几何结构实现物体定位,并且随着年龄的发展逐渐学会利用边界的高度信息(3.1岁～4.7岁)、长度信息(4～5岁)、视觉阻碍性信息(5岁)等完成空间导航。基于这些认知过程,神经影像学研究主要以成人为研究被试,发现大脑中的内侧颞叶和顶叶脑区在边界加工中有着不同功能作用。具体而言,边界的空间几何结构及构成要素(高度、长度和角度)体位置的学习和提取则由海马负责。但是,仍存在一些研究问题值得未来深入S探c讨i。e第n一c,e拓展深化边界促进与后顶叶之间的功能交互。第三,密切关注大脑对场地边界与场地中心编码的心理或神经表征的区别和联系。第四,重点考察阿尔兹海默症有关基因易感人群在基于边界导航的行为受损情况。最后,延伸探讨边界在长时记忆、时间知觉、视觉空间、社交网络等领域的影响机制。     

ASSESSMENT OF STEREOTYPIC AND SELF-INJURIOUS BEHAVIOR AS ADJUNCTIVE RESPONSES

Certain responses of both humans and nonhumans appear to be maintained indirectly by intermittent reinforcement schedules and have been referred to collectively as adjunctive behavior. Although basic research has examined adjunctive behavior extensively, relatively few studies have been conducted with humans, particularly those with developmental disabilities who often engage in frequent and varied stereotypic behavior. This study assessed possible adjunctive characteristics of self-injurious and stereotypic behaviors using a multielement design containing two types of control conditions. Four subjects who engaged in both self-injurious behavior and stereotypy participated after variables maintaining their self-injury were identified via functional analyses. Each day, subjects were exposed to three 15-min sessions in random order: (a) noncontingent presentation of food on a fixed-time schedule (e.g., FT 30 s), (b) a massed-reinforcement (food) control, and (c) a no-reinforcement control. A variety of fixed-time schedules were examined during different experimental phases. Results of this preliminary study suggested that self-injury was not induced by intermittent reinforcement schedules, whereas the stereotypic behavior of some individuals showed characteristics of adjunctive behavior. The importance of research on adjunctive behavior and suggestions for future studies are discussed.     

TRANSFER OF BEHAVIORAL FUNCTION AS A CONTRIBUTING FACTOR IN TREATMENT RELAPSE

When relapse occurs following successful treatment to reduce problem behavior, it is often attributed to inconsistent implementation of maintenance programs. Although less likely, another potential cause for relapse is a change in the behavior's maintaining contingency over time. To examine this possibility, additional assessment was conducted with 4 individuals who were rereferred to a day-treatment program due to recurrence of their self-injurious behavior (SIB) 2 months to 2 years following successful treatment. In each case, the original treatment had been developed and implemented based on the outcome of functional analysis assessments. For 1 subject, results of a second functional analysis were consistent with those from the original assessment, indicating that the function of her SIB had remained unchanged. For the other 3 subjects, results of the second assessment suggested that their SIB had acquired new or additional functions. These findings indicate that factors other than program inconsistency can lead to relapse, and that clinical revaluation for such cases should include a current functional analysis to determine if new treatment components are needed.     

THE IMPACT OF FUNCTIONAL ANALYSIS METHODOLOGY ON OUTPATIENT CLINIC SERVICES

The impact of the article by Iwata, Dorsey, Slifer, Bauman, and Richman (1982) on research in severe behavior disorders has been impressive. Equally impressive, however, but not as fully recognized, has been the impact of this methodology on the routine professional activities of those who employ functional analysis methods in their daily work. As one example of this impact, we describe the evolution of assessment procedures based on “brief functional analysis” methodology in our outpatient clinics. Less apparent have been the collateral effects that occur from using these procedures. Interactions with clients and colleagues have changed in ways that result in increased positive reinforcement. In this article, we briefly discuss the positive impact functional analysis has had on one specific work behavior—outpatient clinic assessment—and describe some of the generalized effects we have experienced in related aspects of our daily professional activities.     

Interlimb coordination: Learning and transfer under different feedback conditions

The role of intrinsic and extrinsic information feedback in learning a new bimanual coordination pattern was investigated. The pattern required continuous flexion-extension movements of the upper limbs with a 90 ° phase offset. Separate groups practiced the task under one of the following visual feedback conditions: (a) blindfolded (reduced FB group), (b) with normal vision (normal FB group), or (c) with concurrent relative motion information (enhanced FB group). All groups were subjected to three different transfer test conditions at regular intervals during practice. These tests included reduced, normal vision, and enhanced vision conditions. Experiment 1 showed that the group receiving augmented information feedback about its relative motions in real-time produced the required coordination pattern more successfully than the remaining two groups, irrespective of the transfer conditions under which performance was evaluated. Experiment 2 replicated and extended the superiority of the enhanced feedback group during acquisition and retention. Experiment 3 demonstrated that successful transfer to various transfer test conditions was not a result of test-trial effects. Overall, the data suggest that the conditions that optimized performance of the coordination pattern during acquisition also optimized transfer performance.     

IDENTIFYING INSTRUCTIONAL TASKS THAT OCCASION PROBLEM BEHAVIORS AND ASSESSING THE EFFECTS OF STUDENT VERSUS TEACHER CHOICE AMONG THESE TASKS

Levels of problem behavior were assessed when 4 students with severe disabilities received instruction on preferred versus nonpreferred tasks and when tasks of each type were chosen by the teacher rather than by the student. In Phase 1, interview and direct observation assessments were conducted to identify relative preferences for academic tasks. In Phase 2, the effects of these lower preference and higher preference tasks on the rate of problem behavior were evaluated using a multielement design. The results showed that lower preference tasks were associated with higher rates of problem behaviors and that students, when given a choice, consistently selected the tasks that had been identified through interview and direct observation as higher preference. In Phase 3, we assessed whether allowing the students to choose between pairs of lower preference tasks or between pairs of higher preference tasks reduced problem behavior relative to a condition in which the teacher selected the same tasks. For 2 of 4 students, the rates of problem behavior were lower when students (rather than the teacher) selected the lower preference activity. Higher preference tasks for 3 students were associated with relatively low rates of problem behavior regardless of whether the student or the teacher selected the task.