Word meanings can be accessed but not reported during the attentional blink.

After the detection of a target item in a rapid stream of visual stimuli, there is a period of 400-600 ms during which subsequent targets are missed. This impairment has been labelled the 'attentional blink'. It has been suggested that, unlike an eye blink, the additional blink does not reflect a suppression of perceptual processing, but instead reflects a loss of information at a postperceptual stage, such as visual short-term memory.

Induction of nitric oxide synthesis in murine macrophages by Helicobacter pylori.

Intact Helicobacter pylori cells, as well as cellular components, stimulated nitric oxide (NO) synthesis in an in vitro murine macrophage system by the L-arginine-nitric oxide pathway. Macrophage-mediated NO formation was dependent on the presence of H. pylori and exhibited a dose-dependent increase at H.

The Slow Time-Course of Visual Attention.

Visual attention is often conceived as a high-speed serial system moving rapidly from one object to another at rates of a few dozen milliseconds per item. We present four experiments demonstrating that this high-speed model is incorrect. Subjects identify two objects, presented at separate times.

Similarity determines the attentional blink.

When participants are required to respond to a target letter imbedded in a stream of rapid serially presented letters, perception of a 2nd target letter is impaired if the interval between the 2 targets is less than about 450 ms. This attentionally based posttarget suppression in visual processing, referred to as the attentional blink (AB), is not found when there is a brief pause in the stream immediately after the 1st target. To investigate the importance of posttarget stimulation in AB production, the categorical, featural, and spatial similarity of the immediate posttarget item to other items in the stream was manipulated.

Comparison of gadolinium-enhanced MR and thallium-201 single photon emission computed tomography in pediatric brain tumors.

Despite its usefulness in adults with cerebral gliomas, indications for thallium-201 single-photon emission computed tomography (SPECT) in pediatric brain tumor patients are not well defined. We prospectively compared thallium SPECT with gadolinium-enhanced MR (Gd-MR) to determine if thallium SPECT provides clinically useful information that cannot be derived from Gd-MR. We studied 24 pediatric brain tumor patients, 7 at presentation and 17 during therapy.

Direct measurement of attentional dwell time in human vision.

In vision, attentional limitations are reflected in interference or reduced accuracy when two objects must be identified at once in a brief display. In our experiments a brief temporal separation was introduced between the two objects to be identified. We measured how long the object continued to interfere with the second, and hence the time course of the first object's attentional demand.

Attention to visual pattern information produces the attentional blink in rapid serial visual presentation.

To-investigate the temporal allocation of attention, a series of 7 experiments using rapid serial visual presentation (RSVP) was designed to examine the relationship of the attentional demands of various target tasks to the production of the subsequent visual attentional deficit, or "attentional blink" (AB), recently reported by J. E. Raymond, K.

The efficacy of shunting the hydrocephalic edema.

The efficacy of shunting the hydrocephalic edema was evaluated by means of transmission electromicroscopical observation (TEM) comparing ultrastructural alterations seen in either valid or invalid shunted feline hydrocephalus. Owning to shunt placement, deteriorated clinical symptoms recovered and one of the observed morphological alterations such as gliosis developed chronologically after the initiation of hydrocephalus. On the other hand, so called hydrocephalic edema observed in the region of periependymal tissue after shunt placement was improved not only in both valid and invalid shunted but also even in sham group however the extent of these alterations were different from each other.

Abnormal brain biomechanics in the hydrocephalic child. From: Concepts in Pediatric Neurosurgery, 1982,vol 2.

Sixteen children with active hydrocephalus were studied using the Pressure Volume Index (PVI) technique to characterize neural axis compliance and the resistance to CSF absorption (Ro). Intracranial pressure for the series was 16.2 +/- 6.

The locus of inhibition in the priming of static objects: object token versus location.

The inhibition witnessed in the negative priming effect has been accounted for by positing an object file containing both identity and location information. In the present study, four experiments with 31 human subjects replicate the negative priming effect and, using new dual-target conditions where subjects respond to the target first perceived on a two-target forced-choice probe trial, suggest that location alone could account for the observed inhibition. Experiment 1 establishes an RT baseline for the new dual-target condition, whereas Experiments 2 and 3 replicate previously found single-target effects under dual-target conditions.

Temporary suppression of visual processing in an RSVP task: an attentional blink?

Through rapid serial visual presentation (RSVP), we asked Ss to identify a partially specified letter (target) and then to detect the presence or absence of a fully specified letter (probe). Whereas targets are accurately identified, probes are poorly detected when they are presented during a 270-ms interval beginning 180 ms after the target. Probes presented immediately after the target or later in the RSVP stream are accurately detected.

Quantitative relationship between oral nitrate-reducing activity and the endogenous formation of N-nitrosoamino acids in humans.

Salivary nitrate and nitrate concentrations, in vitro kinetics of nitrate reduction in saliva, and numbers of salivary nitrate-reducing micro-organisms were each compared with N-nitrosoamino acid excretion in 16 humans eating controlled diets. N-Nitrosoproline (NPRO) and N-nitrosothiazolidine-4-carboxylic acid (NTCA) excretion were measured after intake of nitrate (5.24 mmol) and L-proline (4.

Gastric nitrate reduction and nitrosation of trimethylurea in swine treated with pentagastrin or cimetidine.

Swine were treated with cimetidine in order to quantify the reduction of nitrate to nitrite and the gastric formation of N-nitrosotrimethylurea (NTMU) under conditions similar to those in the achlorhydric human stomach. Gastric-fistulated swine were instilled with 6.0 mmol of nitrate in 50 ml water, after which gastric nitrate, nitrite and pH were monitored.

Temporal processing in dyslexia.

The temporal processing capabilities of 15 children with dyslexia versus 15 age-matched and 15 reading-matched controls in a word identification task were examined. The hypothesis underlying the present experiment was that word recognition would be inferior in children with dyslexia, relative to controls, when the task demanded the temporal integration (sequencing) of two-syllable words. Such a hypothesis must predict that one-syllable word recognition does not distinguish between these two populations and that these effects cannot be accounted for in terms of eye movement differences.

Analysis of dose/time/response relationships for chronic toxic effects: the case of acrylamide.

This case study illustrates how a very simple dynamic modeling approach can extract information of interest for both toxic mechanism research and risk assessment from a series of dose/time/response data. The technique is applicable for effects that are thought to result from damage processes that are reversible, at least at low doses and times of exposure. The data sets analyzed provided information on some specific manifestation of acrylamide neurotoxicity produced by different combinations of acrylamide dose rate and duration of exposure.

Attention to auditory and peripheral visual stimuli: effects of arousal and predictability.

Changes in the distribution of attention among auditory and peripheral visual stimuli were examined in a choice reaction time paradigm. Two variables were manipulated: predictability of stimulus locations and arousal state of subjects. The arousal level of some subjects was raised by occasionally exposing them to brief, mild electric shocks.

Training of efficient oculomotor strategies enhances skill acquisition.

The present study investigated the hypothesis that efficient oculomotor behaviours can be acquired through practice on a series of simple tasks and can be transferred subsequently to a complex visuomotor task, such as a video game. Each of two groups of subjects were exposed to a different set of simple tasks, or drills. One group, the efficient eye movement experimental group, received training designed to minimize eye movements and optimize scan path behaviours, whereas a second group of subjects, the inefficient eye movement experimental group, received training designed to increase the frequency of eye movements.

The impact of anxiety on visual attention to central and peripheral events.

Recent reports in the literature suggest that anxious individuals show an attentional bias to mood-congruent information. Various investigators have hypothesized that such anxiety-based coding biases contribute to the maintenance of mood disorders. The present study sought to determine if attentional biases in anxious subjects extends to the perception of neutral, as opposed to affect-laden, stimuli.

The theoretical requirements of shunt design as determined by biomechanical testing in pediatric hydrocephalus.

This paper reviews the mechanics of shunts currently used to treat hydrocephalus and contrasts these devices with the normal mechanism of CSF circulation. These differences are examined with reference to the biomechanical testing performed in hydrocephalus children. These studies show that in most untreated hydrocephalics, enhanced volume storage accompanies a partial absorptive defect.