Time-Resolved and Spatio-Temporal Analysis of Complex Cognitive Processes and their Role in Disorders like Developmental Dyscalculia

The aim of this article is to report on the importance and challenges of a time-resolved and spatio-temporal analysis of fMRI data from complex cognitive processes and associated disorders using a study on developmental dyscalculia (DD). Participants underwent fMRI while judging the incorrectness of multiplication results, and the data were analyzed using a sequence of methods, each of which progressively provided more a detailed picture of the spatio-temporal aspect of this disease. Healthy subjects and subjects with DD performed alike behaviorally though they exhibited parietal disparities using traditional voxel-based group analyses. Further and more detailed differences, however, surfaced with a time-resolved examination of the neural responses during the experiment. While performing inter-group comparisons, a third group of subjects with dyslexia (DL) but with no arithmetic difficulties was included to test the specificity of the analysis and strengthen the statistical base with overall fifty-eight subjects. Surprisingly, the analysis showed a functional dissimilarity during an initial reading phase for the group of dyslexic but otherwise normal subjects, with respect to controls, even though only numerical digits and no alphabetic characters were presented. Thus our results suggest that time-resolved multi-variate analysis of complex experimental paradigms has the ability to yield powerful new clinical insights about abnormal brain function. Similarly, a detailed compilation of aberrations in the functional cascade may have much greater potential to delineate the core processing problems in mental disorders.     

Enhancing the reading of dyslexic children by reading acceleration and auditory masking.

This research attempted to improve the reading performance of dyslexic children through two different methods: reading acceleration and auditory masking. Participants were 52 dyslexic children and 52 reading-level matched normal, novice readers. Results indicated that whereas acceleration improved reading performance in both groups, auditory masking was beneficial to dyslexic children only. Furthermore, a combined condition of both acceleration and masking was the most effective in enhancing dyslexic children's comprehension. It is argued that because normal readers use the phonological route quite effectively, its masking is detrimental to performance. On the other hand, auditory masking reduces the impact of the presumed phonological impairment of dyslexic children. Analysis of decoding mistakes suggested that both manipulations might have resulted in a more effective utilization of orthographic information and enhanced top-down context effects for dyslexic and novice readers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental induction and termination of acute psychological stress in human volunteers: effects on immunological, neuroendocrine, cardiovascular, and psychological parameters

The present research investigated the effects of controlled experimental manipulations of stress on biological and psychological reactions. Fifty young adult male volunteers were exposed to a 12-min period of stress induced by the threat of an unavoidable, painful electric shock. A 12-min period without this threat preceded or followed the stress period. Blood was drawn during the 4th and the 12th minute of each period. Anticipatory threat led to significant elevations in the proportions and cytotoxic activity of natural killer (NK) lymphocytes, plasma epinephrine levels, pulse rate, and reported level of tension, and to a reduction in the CD4/CD8 ratios. The no-threat period induced a return to baseline values for epinephrine, pulse rate, and tension, and lower than baseline levels for cytotoxic activity of NK lymphocytes, within a similarly short time span. The findings underline the rapidity with which physiological changes may transpire in the course of a brief and acute period of psychological stress, and the rapidity of their reversal upon relief from the stressor.     

Increasing first graders' reading accuracy and comprehension by accelerating their reading rates.

I carried out four experiments to determine the effects on decoding mistakes and comprehension of test passages at fastest and slowest reading rates. The subjects of the first three studies were 161 Israeli first graders, and those of the last experiment were 61 American first graders reading English. Analysis of reading rates obtained during a self-paced condition provided the base rates for each subject. I hypothesized that because of the constraints of short-term memory, requiring subjects to maintain their own maximal oral reading rates would result in improvements in both reading accuracy and comprehension. When presented with the text at their maximal normal reading rates, subjects averaged fewer reading errors and higher comprehension scores than in the self-paced conditions. By contrast, when the text was presented at the slowest reading rates, subjects' decoding accuracy improved, but their comprehension decreased significantly. In one of the experiments, the text contained deliberate letter-substitution errors. Increased reading rate once more reduced the overall errors and increased comprehension. In addition, the deliberate mistakes were more frequently corrected to normal words than in the self-paced condition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of accelerated reading rate on memory for text.

Based on the finding that increasing stimulus presentation rate can increase short-term memory (STM) span, reading rate was accelerated in a series of experiments that demonstrated substantial gains in reading accuracy and comprehension. The present investigation tested the hypothesis that comprehension gains in fast-paced reading are attributable primarily to changes in STM functioning. A series of standard STM-sensitive tasks were administered in both self-paced and fast-paced reading conditions. The magnitude and relative specificity of effects evident in fast-paced reading confirmed the hypothesis. Several alternative hypotheses were rejected. These findings provide strong support for a causal role for STM function in text processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Collaborative Public Space in a National Innovation System: A Case Study of the Israeli Military's Impact on the Software Industry

Both systems of innovation and cluster theories emphasize the importance of institutions that facilitate learning and information diffusion as well as community building for the continuous success of industrial systems. Nevertheless, they fail to combine their insights into a general system-level understanding. In order to fill this gap the concept of collaborative public space (CPS) is defined. It is then used to analyze the Israeli military's role within the Israeli IT industry, employing the case study method to analyze a specific section of the military—MAMRAM—the main programming, software engineering, and computer users training unit. The paper's main findings are that, contrary to the commonly argued view, which sees the military mainly as a supplier of factors of production such as high skilled labor, or technological spin-offs, the military has been playing a critical role in the continuing success of the high-tech industry by providing it with a CPS. The military acts as an important center of information gathering, processing, and dissemination for the Israeli software innovation system, as the originator and strengthener of many social networks, and as the connecting node between various weakly tied social networks.     

Effects of accelerated reading rate on memory for text among dyslexic readers.

The author tested the hypothesis that gains in reading performance occurring among dyslexic children during individually paced accelerated reading are partially attributable to changes in short-term memory (STM) processing. Dyslexic children's performance on a series of standard STM-sensitive tasks administered during both self- and fast-paced reading conditions confirmed this hypothesis. The findings provided strong support for a causal role of STM functioning in text processing but indicated that reading acceleration enhanced STM only when dyslexic children were able to rely on contextual cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phonological and orthographic processing of Hebrew words: electrophysiological aspects

Brain activity among 15 male, college-level, normal readers in Israel was examined during phonological and orthographic word-recognition tasks. Both electrophysiological (event-related potentials, or ERPs) and behavioral measures were obtained. Data indicated that (a) behavioral accuracy was almost perfect for all the experimental tasks, and (b) although P200 and N400 ERP components were elicited in the experimental tasks, the latencies of those components were significantly longer and their amplitudes significantly higher in the phonological task. Variations in vowel information had no effect on word recognition in either type of task. The results suggest that among skilled readers of Hebrew, phonological processing during word recognition may be more effortful and may demand greater cognitive resources than orthographic processing. Furthermore, the additional phonological information represented in vowels appears to contribute little to word recognition in this population. These findings support earlier research on skilled reading in Hebrew as well as current theoretical models of reading.