扩散张量成像在弱视中应用的探讨

弱视是儿童常见眼科疾病，发病机制目前尚不完全清楚。扩散张量成像（diffusion tensor imaging，DTI）是MRI技术的一个新应用，将DTI引入弱视发病机制的研究使人们能更加直观地研究弱视患者视路相关结构有否解剖改变。正确运用哲学观点、充分发挥创新能力并灵活选用适宜技术与高新技术以期达到弱视诊断的最优化。     

扩散张量成像在弱视中应用的探讨

弱视是儿童常见眼科疾病,发病机制目前尚不完全清楚.扩散张量成像(diffusion tensor imaging,DTI)是MRI技术的一个新应用,将DTI引入弱视发病机制的研究使人们能更加直观地研究弱视患者视路相关结构有否解剖改变.正确运用哲学观点、充分发挥创新能力并灵活选用适宜技术与高新技术以期达到弱视诊断的最优化.     

影像学在弱视发病机制研究中的应用

弱视作为常见的儿童眼病,其发病机制至今仍未完全清楚.近年来神经功能影像学工具和技术不断更新和发展,将其应用于弱视发病机制的研究,为弱视发病机制的中枢神经系统假说提供了有利证据.临床的需求是科技创新的原动力,科技的进步和多学科的合作推动了医学的发展.     

我国食管癌进一步研究的思路

为进一步探讨食管癌的发病机制和寻求食管癌的防治新策略,本文回顾了现代科学技术革命和食管癌研究的发展史,借鉴现代科学技术革命的成功经验,提出将整体的有关调节因素与食管癌发病机制相结合,拓宽综合性和多学科合作的研究思路,可能会发现攻克食管癌防治研究的突破点,同时,创新研究技术和加强实验室建设是加速食管癌研究取得新进展的有效途径。     

我国食管癌进一步研究的思路

为进一步探讨食管癌的发病机制和寻求食管癌的防治新策略,本文回顾了现代科学技术革命和食管癌研究的发展史,借鉴现代科学技术革命的成功经验,提出将整体的有关调节因素与食管癌发病机制相结合,拓宽综合性和多学科合作的研究思路,可能会发现攻克食管癌防治研究的突破点,同时,创新研究技术和加强实验室建设是加速食管癌研究取得新进展的有效途径.     

肠易激综合征发病机制研究中的几个问题

肠易激综合征是一种肠道功能性疾病,是目前消化病领域的研究热点,近10年来肠易激综合征发病机制的研究没有突破性进展,本文从哲学基本原理的视角对肠易激综合征发病机制研究中的困惑进行思考与分析,希望给今后的肠易激综合征发病机制研究带来一些启示。     

慢性失眠的神经影像学研究进展

随着现代社会的发展,失眠障碍的发病率越来越高,已成为常见的社会健康问题。失眠障碍的颅脑结构影像并无明显异常,随着神经影像技术的迅速发展,大脑的研究进入一个可视化的时代,神经功能影像技术越来越多地用于失眠障碍的发病机制及认知功能损害的研究,本文对近年来利用神经影像技术针对慢性失眠的发病机制、认知损害和情感异常的研究进行综述。     

肠易激综合征发病机制研究中的几个问题

肠易激综合征是一种肠道功能性疾病,是目前消化病领域的研究热点,近10年来肠易激综合征发病机制的研究没有突破性进展,本文从哲学基本原理的视角对肠易激综合征发病机制研究中的困惑进行思考与分析,希望给今后的肠易激综合征发病机制研究带来一些启示.     

妊娠期高血压疾病的系统论思考

妊娠期高血压疾病是妊娠期常见而又严重危害母儿健康的疾病。从胎盘浅着床,血管内皮受损,遗传因素,免疫机制探讨了妊娠期高血压疾病的发病机制。随着研究的深入,免疫机制在妊娠期高血压疾病的发病中的作用越来越受到重视。介绍了APS最新的治疗进展,为今后的APS发病机制研究及临床治疗带来更多的启示。     

妊娠期高血压疾病的系统论思考

妊娠期高血压疾病是妊娠期常见而又严重危害母儿健康的疾病.从胎盘浅着床,血管内皮受损,遗传因素,免疫机制探讨了妊娠期高血压疾病的发病机制.随着研究的深入,免疫机制在妊娠期高血压疾病的发病中的作用越来越受到重视.介绍了APS最新的治疗进展,为今后的APS发病机制研究及临床治疗带来更多的启示.     

Mapping the development of white matter tracts with diffusion tensor imaging

In this study, the development of white matter was studied using an optimized diffusion tensor imaging (DTI) protocol in 20 normal subjects (10–40 years old). The normal development of white matter tracts was addressed by comparing the diffusion anisotropy results between two sub‐groups: eight adults (26–38 years old) and eight adolescents (13–15 years old). The difference in myelination extent between these two groups as indexed by the fractional anisotropy was identified by conducting a student t‐test of the measured diffusion anisotropy maps. Significant differences (p < 0.01) were detected in the gyrus frontalis medialis (GFM), gyrus temporalis medialis (GTM) and gyrus cinguli (GC), in addition to the developmental changes in corpus callosum. A brief overview of previous published DTI studies in developmental science and current progress in DTI techniques is also given at the end of this paper. It may be useful for readers interested in using DTI to study developmental problems but who are not familiar with the various technical aspects.     

Microstructural organization of corpus callosum projections to prefrontal cortex predicts bimanual motor learning

The corpus callosum (CC) is the largest white matter tract in the brain. It enables interhemispheric communication, particularly with respect to bimanual coordination. Here, we use diffusion tensor imaging (DTI) in healthy humans to determine the extent to which structural organization of subregions within the CC would predict how well subjects learn a novel bimanual task. A single DTI scan was taken prior to training. Participants then practiced a bimanual visuomotor task over the course of 2 wk, consisting of multiple coordination patterns. Findings revealed that the predictive power of fractional anisotropy (FA) was a function of CC subregion and practice. That is, FA of the anterior CC, which projects to the prefrontal cortex, predicted bimanual learning rather than the middle CC regions, which connect primary motor cortex. This correlation was specific in that FA correlated significantly with performance of the most difficult frequency ratios tested and not the innately preferred, isochronous frequency ratio. Moreover, the effect was only evident after training and not at initiation of practice. This is the first DTI study in healthy adults which demonstrates that white matter organization of the interhemispheric connections between the prefrontal structures is strongly correlated with motor learning capability.     

医学人文素质教育与小班化教学

中国医学人文教育正处于起步、探索阶段,课堂教学是主要渠道和途径,而目前各校的医学人文教育采取的大班课教学方式影响了教学效果.从医学人文教育的理念和教育规律出发,并借鉴他国的经验,小班化教学应是落实人文教育的实效性一个中心环节.     

Maintenance of Parent-Implemented Discrete-Trial Instruction during Videoconferencing

Access to behavior-analytic professionals who can implement interventions like discrete-trial instruction (DTI) may be limited for families living in rural communities. We trained four rural parents of children with autism to implement DTI accurately with a confederate using in vivo behavioral skills training. The DTI skills that parents demonstrated with a confederate generalized to working with their children. We then assessed whether periodic supervision during videoconferencing maintained parents’ DTI skills following training. Parents accurately implemented untrained DTI programs with their children and maintained accurate implementation over several months of remote supervision occurring twice a week, weekly, and biweekly. Videoconferencing may be an effective way for individuals responsible for direct implementation to maintain contact with behavior analysts who are not locally accessible.     

Transitioning from rich to lean reinforcement as a form of error correction

Discrete trial instruction (DTI) is a ubiquitous tool used by practitioners in early intervention programs. A common approach to correcting errors during DTI involves providing a single prompt of the target response when a mistake is made (i.e., single-response repetition). Modifications to the single-response repetition approach have been developed to improve acquisition; however, these modifications are often aversive techniques (e.g., increased effort, response cost) and may not be preferred by the children or considered socially acceptable by caregivers. We conducted this study to evaluate the use of a transition from rich to lean reinforcement as a form of error correction. We compared the rich–lean condition to the single-response repetition approach during DTI for 4 boys diagnosed with autism. The rich–lean condition was (a) more efficient in improving accuracy in 6 out of 9 tasks, (b) more preferred by all participants, and (c) socially validated by caregivers.     

Diffusion-tensor imaging of cognitive performance

MR methods have for some years been used to assess cognitive performance. Recently, studies have shown that diffusion-tensor imaging (DTI), which provides noninvasive maps of microscopic structural information of oriented tissue in vivo, is finding utility in studies of cognition in the normal and abnormal aging population. These studies suggest that water proton nonrandom, anisotropic diffusion measured by DTI is highly sensitive to otherwise subtle disease processes not easily seen with conventional MRI tissue contrast mechanisms and raises new issues of the role of MR in assessing cognitive potential.     

Interactive computer training to teach discrete‐trial instruction to undergraduates and special educators in Brazil: A replication and extension

Discrete‐trial instruction (DTI) is a behavioral method of teaching young children with autism spectrum disorders (ASD) that has received a significant amount of research support. Because of a lack of qualified trainers in many areas of the world, researchers have recently begun to investigate alternative methods of training professionals to implement behavioral teaching procedures. One promising training method is interactive computer training, in which slides with recorded narration, video modeling, and embedded evaluation of content knowledge are used to teach a skill. In the present study, the effectiveness of interactive computer training developed by Pollard, Higbee, Akers, and Brodhead (2014), translated into Brazilian Portuguese, was evaluated with 4 university students (Study 1) and 4 special education teachers (Study 2). We evaluated the effectiveness of training on DTI skills during role‐plays with research assistants (Study 1) and during DTI sessions with young children with ASD (Studies 1 and 2) using a multiple baseline design. All participants acquired DTI skills after interactive computer training, although 5 of 8 participants required some form of feedback to reach proficiency. Responding generalized to untaught teaching programs for all participants. We evaluated maintenance with the teachers in Study 2, and DTI skills were maintained with 3 of 4 participants.     

The effects of video modeling with voiceover instruction on accurate implementation of discrete-trial instruction

The present study replicates and extends previous research on the use of video modeling (VM) with voiceover instruction to train staff to implement discrete-trial instruction (DTI). After staff trainees reached the mastery criterion when teaching an adult confederate with VM, they taught a child with a developmental disability using DTI. The results showed that the staff trainees' accurate implementation of DTI remained high, and both child participants acquired new skills. These findings provide additional support that VM may be an effective method to train staff members to conduct DTI.     

What Does Diffusion Tensor Imaging Reveal About the Brain and Cognition in Fetal Alcohol Spectrum Disorders?

Over the past 5 years, Diffusion Tensor Imaging (DTI) has begun to provide new evidence about the effects of prenatal alcohol exposure on white matter development. DTI, which examines microstructural tissue integrity, is sensitive to more subtle white matter abnormalities than traditional volumetric MRI methods. Thus far, the available DTI data suggest that white matter microstructural abnormalities fall on a continuum of severity in Fetal Alcohol Spectrum Disorder (FASD). Abnormalities are prominent in the corpus callosum, but also evident in major anterior-posterior fiber bundles, corticospinal tracts, and cerebellum. These subtle abnormalities are correlated with neurocognitive deficits, especially in processing speed, non-verbal ability, and executive functioning. Future studies using larger samples, increasingly sophisticated DTI methods, and additional functional MRI connectivity measures will better characterize the full range of abnormalities in FASD. Ultimately, these measures may serve as indices of change in future longitudinal studies and in studies of interventions for FASD.     

A Comparison of Structural Brain Imaging Findings in Autism Spectrum Disorder and Attention-Deficit Hyperactivity Disorder

ASD and ADHD are regarded as distinct disorders in the current DSM-5. However, recent research and the RDoC initiative are recognizing considerable overlap in the clinical presentation of ASD, ADHD, and other neurodevelopmental disorders. In spite of numerous neuroimaging findings in ASD and ADHD, the extent to which either of the above views are supported remains equivocal. Here we compare structural MRI and DTI literature in ASD and ADHD. Our main findings reveal both distinct and shared neural features. Distinct expressions were in total brain volume (ASD: increased volume, ADHD: decreased volume), amygdala (ASD: overgrowth, ADHD: normal), and internal capsule (ASD: unclear, ADHD: reduced FA in DTI). Considerable overlap was noted in the corpus callosum and cerebellum (lower volume in structural MRI and decreased FA in DTI), and superior longitudinal fasciculus (reduced FA in DTI). In addition, we identify brain regions which have not been studied in depth and require more research. We discuss relationships between brain features and symptomatology. We conclude by addressing limitations of current neuroimaging research and offer approaches that account for clinical heterogeneity to better distinguish brain-behavior relationships.