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At least 1,387 records · Page 77Linked to original sources

PubMed2003

Speed of lower-level auditory and visual processing as a basic factor in dyslexia: electrophysiological evidence.

This study investigated speed of processing (SOP) among college-level adult dyslexic and normal readers in nonlinguistic and sublexical linguistic auditory and visual oddball tasks, and a nonlinguistic cross-modal choice reaction task. Behavioral and electrophysiological (ERP) measures were obtained. The results revealed that between both groups, reaction times (RT) were longer and the latencies of P2 and P3 components occurred later in the visual as compared to auditory oddball tasks. RT and ERP latencies were longest in the cross-modal task. RT and ERP latencies were delayed among dyslexic as compared to normal readers across tasks. On the oddball tasks, group differences in brain activity were observed only when responding to low-probability targets. These differences were largest for the P3 component, and most pronounced in the case of phonemes. The gap between ERP latencies in the visual versus the auditory modalities for each component was larger among dyslexic as compared to normal readers, and was particularly evident at the linguistic level. A hypothesis is proposed that suggests an amodal, basic SOP deficit among dyslexic readers. The slower cross-modal SOP is attributed to slower information processing in general and to disproportionate "asynchrony" between SOP in the visual versus the auditory system. It is suggested that excessive asynchrony in the SOP of the two systems may be one of the underlying causes of dyslexics' impaired reading skills.

Adult↗

PubMedDate not supplied

FAZYTAN: a system for fast automated cell segmentation, cell image analysis and feature extraction based on TV-image pickup and parallel processing.

Cell location, segmentation and feature extraction of cell images are principal tasks of a high-resolution system for automated cytology. To perform these tasks with high speed, image processing algorithms and the architecture of a processor have to be optimized mutually. This has led to the development of a fast system for the evaluation of cytologic samples based on an optimized TV microscope, a host minicomputer with different peripheral array processors and digital image storages. The processors are optimized in speed for two-dimensional local operations to investigate neighborhood relations and morphology in cell images. Two-dimensional transformations of TV images (288 x 512 x 8 bit) can be carried out within 20 to 200 msec. The processors are able to realize linear filter functions (correlation, convolution) as well as nonlinear functions (median filtering). A set of measurements like area, circumference and connectivity can be derived parallely from one image in 20 msec. The system performs efficient and fast detection and segmentation of cells scanned in one TV frame within one second as well as the extraction of a large number of morphologic features within a few seconds. Based on these procedures, high-resolution analysis of several thousand cells of a sample within one minute will be possible.

Autoanalysis↗

PubMed2006

Etiological heterogeneity and intelligence test scores in patients with schizophrenia.

Previous research has indicated that patients with a family history of schizophrenia show a greater degree of cognitive and neuropsychological impairment than patients without a family history. We examined the neurocognitive performance, using the WAIS-R, of 51 patients with a family history (familial) and 103 patients without a family history (sporadic) to determine if differences exist that may help to explain the heterogeneous neuropsychological profile of the illness. The family history groups did not differ with respect to gender, diagnosis, ethnicity, age, age of onset, education or duration of illness. Multivariate analyses, covarying for age of onset and education, showed the sporadic group performed significantly better than the familial group on the digit symbol and object assembly subtests, with a trend level difference in overall performance IQ score. Additionally, we identified significant gender differences in favor of males for full scale and verbal IQ, the information, digit span, block design, and arithmetic subtests, and at a trend level, the picture assembly subtest. The family history group differences reflect relative dysfunction in visual attention and scanning, visuomotor control, and spatial processing and reasoning. Overall, the results suggest that sporadic patients have better perceptual-organizational skills and faster speed of processing.

Adult↗

PubMed2002

[Studies of psychophysiological functions of middle school age students after prolonged physical training].

Longitudinal researches of neurodynamical functions of pupils 11-15 y. of control and sport classes were executed. The comparative analysis of the study's materials has shown that the research objects with the high level of properties of the basis nervous processes are characterized by faster and more intensive changes of the neurodynamical functions. Long-lasting physical loadings in dependence on typological gradation provide more intensive sensomotor reactions' activation of some functions of attention. At the boys of sports classes the higher functional mobility of the basic nervous processes provide a shorter latent period of the complex sensomotor reactions of a choice, more intensive activation of speed of processing of the information and switching of attention. All parameters (which were analysed) of neurodynamical functions undergo changes, which character depends on duration of influence of physical loadings.

Adolescent↗

PubMed1997

Is the age-complexity effect mediated by reductions in a general processing resource?

The rate of information processing, as revealed in measures of reaction time, slows with advancing age and this slowing is most evident as processing complexity increases. This phenomenon, known as the Age-Complexity effect, has been attributed to general changes in the speed of processing that affect all components of processing indiscriminantly, both within and across tasks in a particular processing domain. That the slowing is thought to be task- and process-independent has led to the additional inference that it reflects reductions in a general processing resource. On the basis of converging evidence identified in a review of both behavioral and chronopsychophysiological studies, we argue that the slowing induced by older age is not generalized, but rather is both task-dependent and process-specific and, as such, cannot be explained in terms of a diminished general processing resource. We close by speculating that elements of the age-induced slowing can be interpreted within the context of the cognitive-energetical model.

Age Factors↗

PubMed2005

Impaired phonological and orthographic word representations among adult dyslexic readers: evidence from event-related potentials.

The authors examined the processing of phonological and orthographic word representations among 17 dyslexic and 16 normal college-level readers using Event-Related Potential measures. They focused on 2 early components--the P200 and the P300. The results revealed P200 and P300 components of lower amplitude and later latency among dyslexic readers than among normal readers for both types of word representation. Group differences were greatest for phonological representations. In addition, the authors observed greater time gaps among dyslexic readers than among normal readers between different processing stages (i.e., between P2 and P3 peaks, between P3 and reaction time). Combined, the data suggest a consistent speed-of-processing deficit among dyslexic readers that is evident within and between stages of cognitive processing. The results are discussed in the context of deficits in stimulus encoding and working memory. In addition, the authors discuss the need for accurate timing and synchronization of phonological and orthographic codes for efficient word recognition.

Adult↗

PubMed2004

The two motor domains of KIF3A/B coordinate for processive motility and move at different speeds.

KIF3A/B, a kinesin involved in intraflagellar transport and Golgi trafficking, is distinctive because it contains two nonidentical motor domains. Our hypothesis is that the two heads have distinct functional properties, which are tuned to maximize the performance of the wild-type heterodimer. To test this, we investigated the motility of wild-type KIF3A/B heterodimer and chimaeric KIF3A/A and KIF3B/B homodimers made by splicing the head of one subunit to the rod and tail of the other. The first result is that KIF3A/B is processive, consistent with its transport function in cells. Secondly, the KIF3B/B homodimer moves at twice the speed of the wild-type motor but has reduced processivity, suggesting a trade-off between speed and processivity. Third, the KIF3A/A homodimer moves fivefold slower than wild-type, demonstrating distinct functional differences between the two heads. The heterodimer speed cannot be accounted for by a sequential head model in which the two heads alternate along the microtubule with identical speeds as in the homodimers. Instead, the data are consistent with a coordinated head model in which detachment of the slow KIF3A head from the microtubule is accelerated roughly threefold by the KIF3B head.

Alternative Splicing↗

PubMed2004

Can flies help humans treat neurodegenerative diseases?

Neurodegenerative diseases are becoming increasingly common as life expectancy increases. Recent years have seen tremendous progress in the identification of genes that cause these diseases. While mutations have been found and cellular processes defined that are altered in the disease state, the identification of treatments and cures has proven more elusive. The process of finding drugs and therapies to treat human diseases can be slow, expensive and frustrating. Can model organisms such as Drosophila speed the process of finding cures and treatments for human neurodegenerative diseases? We pose three questions, (1) can one mimic the essential features of human diseases in an organism like Drosophila, (2) can one cure a model organisms of human disease and (3) will these efforts accelerate the identification of useful therapies for testing in mice and ultimately humans? Here we focus on the use of Drosophila to identify potential treatments for neurodegenerative diseases such as Huntington's and we discuss how well these therapies translate into mammalian systems.

Animals↗

PubMed2022

Engineered helicase replaces thermocycler in DNA amplification while retaining desired PCR characteristics.

Polymerase Chain Reaction (PCR) is an essential method in molecular diagnostics and life sciences. PCR requires thermal cycling for heating the DNA for strand separation and cooling it for replication. The process uses a specialized hardware and exposes biomolecules to temperatures above 95 °C. Here, we engineer a PcrA M6 helicase with enhanced speed and processivity to replace the heating step by enzymatic DNA unwinding while retaining desired PCR characteristics. We name this isothermal amplification method SHARP (SSB-Helicase Assisted Rapid PCR) because it uses the engineered helicase and single-stranded DNA binding protein (SSB) in addition to standard PCR reagents. SHARP can generate amplicons with lengths of up to 6000 base pairs. SHARP can produce functional DNA, a plasmid that imparts cells with antibiotic resistance, and can amplify specific fragments from genomic DNA of human cells. We further use SHARP to assess the outcome of CRISPR-Cas9 editing at endogenous genomic sites.

Humans↗

PubMed2000

Use of marketing to disseminate brief alcohol intervention to general practitioners: promoting health care interventions to health promoters.

Health research findings are of little benefit to patients or society if they do not reach the audience they are intended to influence. Thus, a dissemination strategy is needed to target new findings at its user group and encourage a process of consideration and adoption or rejection. Social marketing techniques can be utilized to aid successful dissemination of research findings and to speed the process by which new information reaches practice. Principles of social marketing include manipulating the marketing mix of product, price, place and promotion. This paper describes the development of a marketing approach and the outcomes from a trial evaluating the effectiveness and cost-effectiveness of manipulating promotional strategies to disseminate actively a screening and brief alcohol intervention (SBI) programme to general practitioners (GPs). The promotional strategies consisted of postal marketing, telemarketing and personal marketing. The study took place in general practices across the Northern and Yorkshire Regional Health Authority. Of the 614 GPs eligible for the study, one per practice, 321 (52%) took the programme and of those available to use it for 3 months (315), 128 (41%) actively considered doing so, 73 (23%) actually went on to use it. Analysis of the specific impact of the three different promotional strategies revealed that while personal marketing was the most effective overall dissemination and implementation strategy, telemarketing was more cost-effective. The findings of our work show that using a marketing approach is promising for conveying research findings to GPs and in particular a focus on promotional strategies can facilitate high levels of uptake and consideration in this target group.

Alcohol Drinking↗

PubMedDate not supplied

Long-term cognitive sequelae of solvent intoxication.

Memory problems lasting 8 months have previously been described for a small group of female solvent workers following an accidental workplace solvent intoxication. Three years after the intoxication the presence of longer-term residual impairment of cognitive functions was evaluated. The major residual difficulty uncovered related to the speed of processing linguistic material, with workers showing slower verification on tasks probing syntactic and semantic reasoning within the context of relatively unimpaired response execution speeds. Of particular interest was the intoxicated workers' difficulty with the conceptually more complex negative syntactic reasoning problems. This difficulty was also shared by solvent workers who were not involved in that accidental intoxication. In addition, decision fatigue was observed following prolonged responding in a continuous choice reaction time task, although ability to maintain vigilance and concentration were unaffected. Taken together, these findings indicate that a single solvent intoxication can give rise to long-term cognitive sequelae in solvent workers.

Adult↗

PubMed2003

Discrimination of single features and conjunctions by children.

Stimuli that are discriminated by a conjunction of features can show more rapid early processing in adults. To determine how this facilitation effect develops, the processing of visual features and their conjunction was examined in 7-12-year-old children. The children completed a series of tasks in which they made a target-non-target judgement as a function of shape only, colour only or shape and colour features, while event-related potentials were recorded. To assess early stages of feature processing the posteriorly distributed P1 and N1 were analysed. Attentional effects were seen for both components. P1 had a shorter latency and P1 and N1 had larger amplitudes to targets than non-targets. Task effects were driven by the conjunction task. P1 amplitude was largest, while N1 amplitude was smallest for the conjunction targets. In contrast to larger left-sided N1 in adults, N1 had a symmetrical distribution in the children. N1 latency was shortest for the conjunction targets in the 9-10-year olds and 11-12-year olds, demonstrating facilitation in children, but which continued to develop over the pre-teen years. These data underline the sensitivity of early stages of processing to both top-down modulations and the parallel binding of non-spatial features in young children. Furthermore, facilitation effects, increased speed of processing when features need to be conjoined, mature in mid-childhood, arguing against a hierarchical model of visual processing, and supporting a rapid, integrated facilitative model.

Aging↗

PubMed2004

Event-related potentials and time course of the "other-race" face classification advantage.

Other-race faces are less accurately recognized than same race faces but classified faster by race. Using event-related potentials (ERPs), we captured the brain temporal dynamics of face classification by race processing performed by 12 Caucasian participants. As expected, participants were faster to classify by race Asian than Caucasian faces. ERPs results identified the occurrence of the other-race face classification advantage at around 240 ms, in a stage related to the processing of visual information at the semantic level. The elaboration of individual face structural representation, reflected in the N170 face-sensitive component, was insufficient to achieve this process. Altogether, these findings suggest that the lesser experience of other-race faces engender fewer semantic representations, which in turn accelerate their speed of processing.

Abstracting and Indexing↗

PubMed2002

Haptic interaction with highly detailed objects.

Haptic exploration of detailed models from patient specific anatomical structures places high demands on computational resources. Constant collision detection and correct calculation of forces fed back to the operator quickly exceed available processing power with increasing level of detail of the represented objects. To alleviate the strain on computational resources optimisation schemes are employed to speed up processing and guarantee glitch-free operation as well as smooth haptic feedback. Among these are the generation of a local haptic model, a look-ahead strategy to increase its range of validity, small world-shift operations and force extrapolation algorithms for smooth feedback.

Algorithms↗

PubMed1998

Integrating the healthcare supply chain.

Today's integrated delivery systems (IDSs) require efficient supply chain processes to speed products to users at the lowest possible cost. Most excess costs within the supply chain are a result of inefficient and redundant processes involved in the transport and delivery of supplies from suppliers to healthcare providers. By integrating and assuming control of these supply chain processes, improving supply chain management practices, and organizing and implementing a disciplined redesign plan, IDSs can achieve substantial savings and better focus their organizations on their core patient care mission.

Benchmarking↗

PubMed1998

Microwave procedures for electron microscopy and resin-embedded sections.

Microwaves now have well-established applications in routine light microscopy. They are employed in tissue fixation and to accelerate a wide spectrum of staining procedures. Besides producing superior preservation of cellular antigens through microwave fixation, this form of irradiation has been employed for antigen retrieval, a procedure that has been a major factor in the optimization of immunolabelling in paraffin sections and cytological preparations. A commercial tissue processor has recently been developed which employs microwaves in a markedly accelerated, one-step processing of tissue blocks, completing the procedure within a fraction of conventional times. Microwaves have also been successfully applied in a variety of molecular techniques such as in situ hybridization and polymerase chain reaction. The adoption of microwaves in electron microscopic procedures has been slower, largely because the requirement for speed in processing is not as great, except in diagnostic samples. However, as this review will show, there are equally as many innovative applications of microwaves in electron microscopy. Microwaves have been employed for rapid processing of fine needle aspiration biopsy samples, in keeping with the requirement for speed in this method of diagnosis. Ultrafast fixation of tissue samples has resulted in the better demonstration of cellular enzymes and proteins. It has been clearly shown that microwave-stimulated on grid staining in uranyl acetate and lead citrate produces more consistent results and without background precipitation. Microwaves can be used to hasten resin polymerization and exposure to microwaves results in antigen retrieval in both resin-embedded thick sections and for immuno-electron microscopy. Immunolabelling shows enhanced sensitivity and the technique is anticipated to contribute greatly to the optimization of immuno-electron microscopy. The potential for greatly accelerated preparation of samples for electron microscopy exists but is yet to be fully realized.

Image Enhancement↗

PubMed1997

Processing time, imagery, and spatial memory.

Measures of cognitive processing time, imagery skill, and spatial memory span were administered to 128 8- to 20-year-olds. Age correlated positively with spatial memory span and accuracy on the imagery tasks but negatively with times on the cognitive processing and imagery tasks. Results of path analyses and structural-equation modeling were consistent with a causal model in which age-related change in speed of processing is associated with more effective imagery. In turn, imagery is associated with spatial memory span. Age was also associated with imagery and spatial span, indicating that other age-related variables need to be incorporated into the causal model.

Adolescent↗

PubMed2001

Odorants elicit evoked potentials in the human amygdala.

Electroencephalographical (EEG) recording studies have shown that odorants produce olfactory evoked potentials (OEPs) on the scalp surface. However, EEGs can only provide limited information about the intracerebral sources from where the OEPs are generated. By contrast, intracerebral EEG recordings enable direct examination of the electrophysiological activity from a given cerebral area. In the present study, neural activity was recorded from the amygdala of seven epileptic patients undergoing intracerebral EEG recordings prior to surgical treatment for relief of intractable seizures. Two olfactory tests were used: a passive-stimulation test consisting of the successive presentation of 12 common odorants and a suprathreshold detection test including both odorant and non-odorant stimulations. Recordings from the amygdala revealed that all odorant stimulations induced large and reproducible OEPs, whereas the non-odorant stimulations did not. It was also found that repetition of the same odorant stimulation led to a decrease in the latency of the first OEP component. This modulation, which corresponds to a faster olfactory processing, strongly suggests that the amygdala is involved in early olfactory attentional processes. In conclusion, it appears that the human amygdala discriminates the incoming information from the nasal airflow as being odorant or not and, additionally, that its speed of processing is sensitive to recent experience with an odor.

Adolescent↗