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PubMed1982

Food safety assessment reflecting cultural changes, novel hazards, and human values.

An analysis of the cultural values of modern society suggests the desire for an abundant nutritious food supply in all seasons, but at the same time causes increasing concern about the safety of food ingredients. The procedures that give benefits also raise questions of safety. The wide range of societal values cover a spectrum but can be ranked according to their importance. These values will exact a price in the form of some risk. It is possible to balance hazards against cultural values, and benefits are an integral part of the calculus of safety assessment. However, every effort should be made to match the highest benefit with the lowest risk and these considerations have a bearing upon regulatory agencies as they seek to arrive at food safety decisions. A consideration of cultural and human values shifts the regulator's focus from risk only to a quite different task of balancing risks vs benefits in deciding on substances in foods.

Culture↗

PubMed1986

Neurogenesis and gliogenesis in the human brain.

The primary germinal neural epithelium lines the ventricular system of the brain and shows intense mitotic activity. Neuroblasts migrate from a juxtaluminal position to establish neural centres and, when this task is completed, the definitive ependymal epithelial lining of the ventricles develops, shifting the remnants of the germinal epithelium to a subendymal location. The subendymal layer continues to proliferate giving rise to glia in the postnatal brain. Premature arrest of migration of neuroblasts leads to the accumulation of heterotopic nests anywhere along the migratory path. Within such ectopia, neurons may make normal connections or they may remain undifferentiated and later become tumorigenic. The subependymal layer has long been considered the site of original of periventricular gliomas. Some migrating neuroblasts establish secondary germinal centres far removed from the ventricular system. An example of this is the external granular layer of the cerebellum which, in man, persists for the first 6 months of life. Cerebellar neuroblastomas could originate directly from this layer in the neonate, or from remnants of this layer in older individuals.

Animals↗

PubMed2004

The contribution of spatial remapping impairments to unilateral visual neglect.

Left visual neglect following right hemisphere damage is a heterogeneous phenomenon, in which several underlying impairments have been identified. Despite recent advances in understanding the neural and cognitive bases of these impairments, current theories of neglect, particularly those that emphasise attentional deficits, do not explain a number of phenomena, including: 'Ipsilesional' neglect after left orienting. Positive or 'productive' manifestations. Spatial transposition errors. Mislocalisations. Revisiting behaviour during visual search. Lack of awareness for objects toward the contralesional side of space. We propose that these manifestations of neglect can be accounted for by an additional underlying disorder of spatial remapping due to parietal dysfunction. In primary visual areas, retinotopic maps are renewed and thus overwritten at each new ocular fixation. Remapping processes operating in higher-level oculocentric visual maps of the parietal cortex ensure visual integration of these successive retinal images over time and space, by creating a constantly updated representation of stimulus locations in terms of distance and direction from the fovea. They consist in the storage, refreshment and re-localization of the different components of the visual scene that are successively attended during its exploration, and provide spatial constancy of visual perception and a spatial buffer for working memory [Cereb Cortex 5 (1995) 470; Visual Cogn 7 (2000) 17]. We begin this article by reviewing theoretical and experimental arguments that have highlighted the importance of parietal remapping processes in maintaining an accurate representation of space across saccadic shifts. We then focus on findings from the double-step saccade task, [Ann Neurol 38 (1995) 739] as a basis for our model of the role of remapping impairments in many of the symptoms of neglect. From these results, remapping impairments would be demonstrated when a saccade has to be guided across the midline after having fixated an object in either the left or right visual field for patients with either left- or right-side parietal lesions. In addition, patients with right-side lesions will have remapping impairments within the left visual field following a saccade to a left-side target (see Fig. 5). In a large part of the article, we seek to build our hypothesis based on this basic model and more speculative assumptions supported with extensive evidence from the literature.

Attention↗

PubMed2005

The watercolor effect: quantitative evidence for luminance-dependent mechanisms of long-range color assimilation.

When a dark chromatic contour delineating a figure is flanked on the inside by a brighter chromatic contour, the brighter color will spread into the entire enclosed area. This is known as the watercolor effect (WCE). Here we quantified the effect of color spreading using both color-matching and hue-cancellation tasks. Over a wide range of stimulus chromaticities, there was a reliable shift in color appearance that closely followed the direction of the inducing contour. When the contours were equated in luminance, the WCE was still present, but weak. The magnitude of the color spreading increased with increases in luminance contrast between the two contours. Additionally, as the luminance contrast between the contours increased, the chromaticity of the induced color more closely resembled that of the inside contour. The results support the hypothesis that the WCE is mediated by luminance-dependent mechanisms of long-range color assimilation.

Adult↗

PubMed2004

Manipulation of frontal brain asymmetry by cognitive tasks.

The purpose of the present study was to evaluate whether verbal fluency tasks may specifically induce relatively greater left than right hemispheric activation in the dorsolateral prefrontal cortex. The effectiveness of the manipulation was evaluated by EEG, which was recorded during performance of the verbal fluency task and during two control conditions, i.e., a baseline condition without cognitive demands, and a mental arithmetic task, respectively. The results demonstrate that the desired effect can only be achieved in individuals with good performance on the verbal fluency task. Good and poor performers do not only differ in lateral asymmetry, but also in the most affected region within the prefrontal cortex. Whereas good performers show relatively increased activation in the cortical region and hemisphere putatively most specialized for this kind of task (i.e., the left dorsolateral frontal cortex), poor performers show a marked shift of frontopolar asymmetry to the right.

Adolescent↗

PubMed1982

Electrodermal responses to attended and nonattended significant stimuli during dichotic listening.

Some investigators have found that words previously associated with shock elicit electrodermal responses (EDRs) when presented in the nonattended channel of a dichotic listening task. The present experiment tested for this phenomenon while closely monitoring for shifts in attention to the nonattended channel. College student volunteers verbally shadowed a series of unrelated words presented to the attended channel while words made significant by previous association with shock (and semantically related words) were occasionally presented to the nonattended channel. Three principal findings were obtained. Fist, when EDRs were averaged across all trials and across all subjects, it was found that EDRs were elicited by the significant words presented in the nonattended channel. Second, for the subgroup of subjects that had the significant words presented to the right ear (activating the left cerebral hemisphere), it was found that EDRs were elicited by the significant words presented to the left ear (activating the right cerebral hemisphere), it was found that EDRs were elicited by the significant word seven on trials on which there were no apparent shifts in attention. The results of this study indicate the importance of closely controlling and monitoring for shifts in attention and suggest the potential importance of cerebral laterality in mediating EDRs to stimuli presented in a nonatttended channel.

Adult↗

PubMed1987

Abnormal temporal lobe response in Alzheimer's disease during cognitive processing as measured by 11C-2-deoxy-D-glucose and PET.

Elderly controls and probable Alzheimer's disease patients underwent serial positron emission tomography (PET) studies during a baseline condition and while performing a verbal memory task. For the temporal lobes, all 7 Alzheimer patients demonstrated a relative shift in glucose metabolic rates to the right hemisphere during the memory condition relative to baseline, and 5 of 7 controls showed a shift to the left hemisphere. Baseline absolute regional metabolic rates replicate previous findings and were somewhat less useful than the memory challenge in differentiating patients from controls. These results indicate that a temporal lobe abnormality in Alzheimer's disease is related to memory performance.

Aged↗

PubMed2000

The emotional stroop task and chronic pain: what is threatening for chronic pain sufferers?

Using a computer version of the emotional stroop task, it was investigated whether chronic pain patients display an involuntary attentional shift towards pain-related information (sensory, affective pain words and injury related words). Multiple regression analyses were used to investigate which pain and psychosocial variables (pain severity, pain-related fear, pain catastrophizing and negative affect) were predictive of attentional bias. Results indicated: (1) that there was an attentional bias towards the sensory pain words; and (2) that current pain intensity was predictive of the effect. No other attentional effects were found. The results are discussed in terms of possible reasons for the difficulty of demonstrating attentional bias in chronic pain patients.

Attention↗

PubMed2003

Exposure to inhalable flour dust in Canadian flour mills.

In 1999, the American Conference of Governmental Industrial Hygienists (ACGIH(R)) proposed a Threshold Limit Value (TLV(R)) of 0.5 mg/m(3) for flour dust with a sensitization notation. The Labour Program of the Department of Human Resources Development Canada (HRDC), following notice of the intention to set a TLV, conducted a study of the levels of exposure to flour dust in flour mills across Canada to verify existing conditions, as well as to decide whether to adopt the proposed TLV or reference some other value. As part of the study, a relationship between flour dust concentrations obtained by using Institute of Occupational Medicine (IOM) samplers and closed-face 37-mm cassettes was examined and the literature on the health effects of exposure to flour dust was reviewed. A total of 104 millers, packers, sweepers, bakery mix operators, and others (mixed tasks) from 14 flour mills were sampled over an 8-hour work shift using IOM samplers. The results indicate that 101 employees (97.1%) were exposed to levels exceeding 0.5 mg/m(3), 66 employees (67.3%) to levels exceeding 5 mg/m(3), and 44 employees (42.3%) to levels exceeding 10 mg/m(3). For comparison purposes, flour dust measurements were also taken in a highly automated flour mill using state-of-the-art technology. The results suggest that even with the most up-to-date technology and proper cleaning operations in place, the flour milling industry may not be able to reduce the flour dust levels to below the TLV of 0.5 mg/m(3). According to the measurements of inhalable and total dust concentrations, the IOM sampler appears to be a more efficient collector of inhalable airborne particles up to 100 microm than the closed-face 37-mm cassette.

Air Pollutants, Occupational↗

PubMed1998

Stimulus context in hemineglect.

Rightward deviation on bisection of a horizontal line is well described in patients with right brain injury and left hemineglect. Because of the observation that hemineglect patients may bisect very short lines to the left of the true midpoint (the so-called crossover effect), additional models have been proposed to incorporate this finding into existing theories of hemineglect. We investigated a line-length effect in six patients with left hemineglect. When presented with any set of lines of uniform (reference) length, percentage rightward deviation on line bisection remained constant across different line lengths. When lines of a second length were mixed into any uniform set of lines, bisection performance on the reference lines changed. A rightward shift in the perceived midpoint of the reference line occurred if the added lines were shorter than the reference lines; a leftward shift occurred if the added lines were longer. Leftward shifts included shifts across the true midpoint, reproducing the crossover effect. Shifts in the perceived midpoint occurred both on a manual line bisection task and on a line bisection discrimination task in which no manual response was required. We propose that the crossover effect may be part of a more general stimulus-context effect in which the perceived midpoint of a line is related not to absolute length, but to the line's length relative to other lines with which it is presented. Such a context effect has not hitherto been described in the neglect syndrome. A possible mechanism for the effect is a generalization of length estimation produced by the combined influence of the focal stimulus and all stimuli that precede it.

Adult↗

PubMedDate not supplied

The neural basis of visual skill learning: an fMRI study of mirror reading.

The learning of perceptual skills is thought to rely upon multiple regions in the cerebral cortex, but imaging studies have not yet provided evidence about the changes in neural activity that accompany visual skill learning. Functional magnetic resonance imaging (fMRI) was used to examine changes in activation of posterior brain regions associated with the acquisition of mirror-reading skill for novel and practiced stimuli. Multiple regions in the occipital lobe, inferior temporal cortex, superior parietal cortex and cerebellum were involved in the reading of mirror-reversed compared to normally oriented text. For novel stimuli, skilled mirror-reading was associated with decreased activation in the right superior parietal cortex and posterior occipital regions and increased activation in the left inferior temporal lobe. These results suggest that learning to read mirror-reversed text involves a progression from visuospatial transformation to direct recognition of transformed letters. Reading practiced, relative to unpracticed, stimuli was associated with decreased activation in occipital visual cortices, inferior temporal cortex and superior parietal cortex and increased activation in occipito-parietal and lateral temporal regions. By examining skill learning and item-specific repetition priming in the same task, this study demonstrates that both of these forms of learning exhibit shifts in the set of neural structures that contribute to performance.

Brain↗

PubMed1990

Males as helpers: the role of sons, relatives, and friends.

The informal helping networks of most frail elderly people are dominated by women. Men are also involved in helping older people, although most male caregivers are husbands. This paper examines the contributions of men other than husbands who provide assistance to a sample of community-based elderly people. Data were gathered through personal interviews with elders and their primary helpers at two points in time. Male helpers provide intermittent assistance with occasional tasks but less frequently undertake routine household chores. Some evidence indicates a shift toward female caregivers as the elder's functional capacity decreases over time.

Adult↗

PubMed2004

Occupational health services in the UK--challenges and opportunities.

BACKGROUND: A small minority of the UK workforce currently has access to an occupational physician. Reduction in the size of enterprises, the emergence of atypical work patterns and problems recruiting and training occupational health specialists risk making this minority even smaller. AIM: This paper considers the challenges currently facing occupational medicine and how we can improve access to occupational health services (OHS). It aims to highlight some of the diverse internal and external factors that restrict the UK's ability to provide all workers access to OHS. METHOD: A literature review was carried out and combined with awareness of current trends in business and new legislation together with provision of occupational medicine in other countries. RESULTS: Potentially controversial solutions that might help to make OHS more widely accessible were identified and are discussed. It is hoped that these will provoke further debate. CONCLUSION: Individually and organizationally, we must examine and improve capabilities if we are to improve worker access to OHS and deliver targets to reduce occupational ill-health. It is suggested that this requires a strategic shift to apply resources differently. There is need to explore delegation of tasks traditionally performed by doctors to nurses and other staff together with the outsourcing of non-core work. The increased use of telemedicine and the enhanced use of information technology for training, risk assessments, wellness programmes and questionnaire-based health assessments are other developments that should be explored.

Family Practice↗

PubMed2006

Channel smoothing: efficient robust smoothing of low-level signal features.

In this paper, we present a new and efficient method to implement robust smoothing of low-level signal features: B-spline channel smoothing. This method consists of three steps: encoding of the signal features into channels, averaging of the channels, and decoding of the channels. We show that linear smoothing of channels is equivalent to robust smoothing of the signal features if we make use of quadratic B-splines to generate the channels. The linear decoding from B-spline channels allows the derivation of a robust error norm, which is very similar to Tukey's biweight error norm. We compare channel smoothing with three other robust smoothing techniques: nonlinear diffusion, bilateral filtering, and mean-shift filtering, both theoretically and on a 2D orientation-data smoothing task. Channel smoothing is found to be superior in four respects: It has a lower computational complexity, it is easy to implement, it chooses the global minimum error instead of the nearest local minimum, and it can also be used on nonlinear spaces, such as orientation space.

Algorithms↗

PubMed2004

Factor structure of the FACES-III in Japanese university students.

We performed a confirmatory factor analysis for the Family Adaptability and Cohesion Evaluation Scale (FACES-III) using 3865 university students in Japan. We confirmed two factors as in the original version, but there were slight differences with the original one. Some items were deleted in order to obtain sufficient goodness-of-fit indexes in a series of confirmatory factor analyses. Moreover, items 11 "Our family, changes its way of handling tasks," 20 "Parents and children discuss in our family," and 15 "We shift household responsibilities," which were originally categorized as "adaptability" items, were loaded on the "cohesion" factor.

Adaptation, Psychological↗

PubMed1995

Quantified electroencephalographic correlates of neuropsychological deficits in Alzheimer's disease.

The authors examined relationships between quantified EEG (qEEG) variables and neuropsychological performance in 54 consecutive patients with probable Alzheimer's disease (AD). Patients were studied with qEEG and a neuropsychological battery that assessed memory, attention, verbal functions, set-shifting abilities, and procedural learning. More severe memory, attention, and verbal deficits were significantly correlated with lower alpha relative power, and increased theta relative power was significantly correlated with poor set-shifting abilities. No qEEG variables were significantly correlated with the procedural learning task. These correlations between deficits in specific cognitive domains and qEEG bands suggest that qEEG may have an important role in the investigation of the cognitive deficits in AD.

Aged↗

PubMed2005

Decisions regarding resident advancement and dismissal.

An orthopaedic resident had been counseled repeatedly regarding his unprofessional behavior. He had indicated, on multiple occasions, that patient-care tasks had been completed when, in fact, they had not. He had shifted his responsibilities to other residents both with and without their knowledge. Despite acceptable technical skills, he had often been poorly prepared for surgical cases. After repeated guidance sessions, warnings, and admonishments, he was dismissed from his training program.

Attitude of Health Personnel↗

PubMed2002

Combination of magneto- and electroencephalography in studies of monoamine modulation on attention.

The brain monoamines serotonin and dopamine have an important role in the regulation of human cognitive functions. Neural correlates of attention can be studied in millisecond resolution with magnetoencephalography (MEG) and electroencephalography (EEG), which provide complementary views on attentional processing. During "selective attention", a processing negativity (PN) overlaps EEG response to the attended tones. This component can be modulated with drugs affecting dopamine transmission in the brain, such as haloperidol and droperidol, whereas no effects seem to be caused by acute tryptophan depletion (ATD), decreasing serotonin synthesis in the brain. Distinct responses are associated with "involuntary attention". Responses reflecting sound-change detection and initiation of involuntary attention, the mismatch negativity and its magnetic counterpart, appear to be modulated by ATD, but not with haloperidol. Subsequent P3a elicited by actual attention shifting, as well as reorienting negativity reflecting orienting back to a relevant task, are in turn decreased by haloperidol, but not affected by ATD or other serotonin modulators. Serotonin may affect the earliest "preattentive" phases on auditory processing, indexed by mid-latency magnetic responses and NIm, but haloperidol's effects on these parameters are insignificant. Taken together, serotonin and dopamine may have differential effects on attentional processing depending on time after stimulus presentation.

Attention↗