Quantitative CT scan studies in aphasia. I. Infarct size and CT numbers

Infarct si?e (number of 1-mm² pixels in the lesion) on CT scans of 30 aphasia patients was obtained with a semiautomated computer program. The mean number of lesion pixels present per slice containing lesion was approximately 500 for mild aphasias (transcortical motor and conduction), 700 for Wernicke's, 1000 for Broca's, 1500 for mixed, and 2000 for globals. These differences were significant for $\text{11}\text{15}$ of the group pairwise comparisons. When lesion locus was controlled for in the anterior/posterior plane, 73–100% of the aphasia patients were correctly classified as to type of aphasia by a discriminant analysis utilizing only the number of lesion pixels present on two CT slices. Different slice combinations were used for different aphasia group comparisons. There was a significant correlation between severity of aphasia and lesion size. There was a significant correlation between lesion size and the CT numbers in the lesion. This type of analysis may be useful to predict the prognosis for recovery potential in aphasics who have CT scans performed at 2 months poststroke.     

A general framework for the analysis of concept identification tasks

A general framework is presented for concept identification based on hypothesis-testing theory. It is a modification of the duoprocess theory presented by Chumbley (1972). It is shown how Markov models for various complex concept identification tasks may be derived from this framework and how such models may be analyzed by making use of probability generating functions. Two experiments are described. In experiment 1 three tasks were used: two simple tasks, where the subject either only had to select the relevant dimension in order to solve the problem or only had to learn a short list of paired-associates, and a more complex task, where both processes were needed to reach the solution. The results were in general favorable to the theory. Experiment 2 was designed to test the application of the theory to the four-choice concept problem. The predictions of the theory are compared to those of the subproblem learning theory of trabasso and Bower (1964), modified to include a ‘learning-on-errors’ assumption. The fit of the duoprocess theory was reasonably good and superior to that of the subproblem learning theory.     

The effects of symmetry and contour on recognition memory in children

Children in prekindergarten, kindergarten, and second grade were tested on a delayed match-to-sample task using abstract visual patterns. The patterns varied both in type of visual organization (unstructured, diagonally symmetrical, vertically symmetrical, and horizontally symmetrical) and in amount of contour. Following the initial memory task, we attempted to train half of the children at each grade by directing their attention to axes of symmetry; the other half of the children received a control task. Subsequently, the subjects were given a second delayed match-to-sample test. On both pre- and post-training trials, structure influenced performance, especially in the two younger groups. Vertical and horizontal symmetry generally facilitated performance in the prekindergarteners, while all three types of symmetry facilitated performance in the kindergarteners. In addition, children generally responded more accurately to patterns with lower levels of contour. They also made more like-contour than unlike-contour confusions, indicating that quantitative aspects of patterns were encoded. Group differences suggested that both processing capacity and memory increase during the age range studied. Finally, there was no indication that training improved performance at any age.     

The role of exploration in win-shift and win-stay performance on a radial maze

Win-shift spatial memory tasks in a radial maze reinforce animals for avoiding previously visited rewarded arms; win-stay tasks reinforce them for returning to those arms. Win-shift tasks have generally been found much easier to perform, and this may be explained either in terms of foraging models which postulate avoidance of locations where food has been found, or in terms of the predominance of spontaneous alternation (exploration). Experiment 1 examined spontaneous alternation behavior in the radial maze as a function of whether the first visit to an arm had been rewarded or not, and showed that alternation was more probable after nonreward than after reward in both hungry and thirsty rats (a result which conflicts with the foraging account of the win-shift superiority). Experiment 2 replicated the finding that win-stay discrimination performance was inferior to win-shift. A manipulation (lengthening the delay between initial and test choices) which weakens spontaneous alternation, reduced, but did not reverse, the win-shift superiority. In Experiment 3, in order to eliminate the influence of spontaneous alternation, versions of the win-stay and win-shift tasks were devised in which, unlike the original task, all arms were familiar at the choice trial. Under those conditions win-stay was performed better than win-shift. It is concluded that spontaneous alternation plays a major role in many spatial memory tasks, and that the results can best be accounted for by combining principles of exploration and simple associative learning, without recourse to foraging models.     

Uncertainty regulation across cultures: An exploration of individual differences in Chinese and Canadian children in the classroom

This research investigates whether individual differences in uncertainty orientation affect classroom behavior for Chinese and Canadian children. Uncertainty orientation distinguishes between uncertainty-oriented individuals, or those who attempt to attain clarity by finding out for themselves, and certainty-oriented individuals, or those who attempt to maintain clarity by adhering to predictable environments. Although uncertainty orientation is considered an informational variable, uncertainty-oriented children in both countries had higher self-ratings, ratings by other students and ratings by their teachers than certainty-oriented children on a variety of social and achievement behaviours. These results suggest that encouraging a discovery learning style of uncertainty regulation in “UO-centric” cultures may be beneficial.     

Possibilities and limits of mind-reading: A neurophilosophical perspective

Access to other minds once presupposed other individuals’ expressions and narrations. Today, several methods have been developed which can measure brain states relevant for assessments of mental states without 1st person overt external behavior or speech. Functional magnetic resonance imaging and trace conditioning are used clinically to identify patterns of activity in the brain that suggest the presence of consciousness in people suffering from severe consciousness disorders and methods to communicate cerebrally with patients who are motorically unable to communicate. The techniques are also used non-clinically to access subjective awareness in adults and infants. In this article we inspect technical and theoretical limits on brain–machine interface access to other minds. We argue that these techniques hold promises of important medical breakthroughs, open up new vistas of communication, and of understanding the infant mind. Yet they also give rise to ethical concerns, notably misuse as a consequence of hypes and misinterpretations.     

腹膜间皮细胞EMT在腹膜纤维化中的研究进展及意义

腹膜透析是终末期肾衰患者肾脏替代治疗的重要手段,腹膜纤维化导致腹透效能下降及超滤衰竭,制约着腹膜透析的应用。腹膜间皮细胞上皮细胞间充质转化是腹膜纤维化的起始和可逆环节,因此预防和逆转EMT的发生发展可能是阻止和延缓腹膜纤维化、超滤衰竭的最佳策略,并将带来巨大的社会和经济效益。     

P16、CyclinDl和CDK4在结直肠癌组织中表达及意义

细胞周期过程中癌基因的激活与抑癌基因的失活等是造成细胞恶性增殖、转化的重要因素。细胞周期G1／S期各调节因子的异常改变与细胞癌变关系尤为密切。P16、CyclinDl和CDK4均为重要的细胞周期调控蛋白,任何原因导致这些蛋白异常表达时,将引起细胞周期调节失控,导致肿瘤的发生和恶性演进。结直肠癌的发生发展同上述三者关系密切。本实验通过免疫组化方法进行检测结直肠癌组织中P16、CyclinDl和CDK4三者的表达及其与结直肠癌临床指标的关系,为揭示三者在结直肠癌发生发展中的作用提供一定的实验依据。     

Measured Gene–Environment Interactions and Mechanisms Promoting Resilient Development

ABSTRACT— Childhood maltreatment elevates risk for antisocial behavior, depression, and other problems over the life span, but a subset of maltreated individuals avoids maladaptive development and shows resilience. Resilience reflects a dynamic confluence of factors that promotes positive adaptation despite exposure to adverse experiences. Recent replicated findings of gene–environment interactions (abbreviated G × E) involving maltreatment have identified two genes, monoamine oxidase A ( MAOA ) and serotonin transporter ( 5-HTT ), that moderate the association between childhood maltreatment and psychopathology. Accordingly, G × E raise new questions about potential biological mechanisms by which some individuals are able to cope adaptively and function relatively well despite experiencing early adversity. We summarize advances toward greater specification of G × E mechanisms, including genetic and environmental moderation of G × E effects and imaging genomics that provide clues regarding resilience processes in development.