Understanding dissociations in dyscalculia: a brain imaging study of the impact of number size on the cerebral networks for exact and approximate calculation. (1/111)

Neuropsychological studies have revealed different subtypes of dyscalculia, including dissociations between exact calculation and approximation abilities, and an impact of number size on performance. To understand the origins of these effects, we measured cerebral activity with functional MRI at 3 Tesla and event-related potentials while healthy volunteers performed exact and approximate calculation tasks with small and large numbers. Bilateral intraparietal, precentral, dorsolateral and superior prefrontal regions showed greater activation during approximation, while the left inferior prefrontal cortex and the bilateral angular regions were more activated during exact calculation. Increasing number size during exact calculation led to increased activation in the same bilateral intraparietal regions as during approximation, as well the left inferior and superior frontal gyri. Event-related potentials gave access to the temporal dynamics of calculation processes, showing that effects of task and of number size could be found as early as 200-300 ms following problem presentation. Altogether, the results reveal two cerebral networks for number processing. Rote arithmetic operations with small numbers have a greater reliance on left-lateralized regions, presumably encoding numbers in verbal format. Approximation and exact calculation with large numbers, however, put heavier emphasis on the left and right parietal cortices, which may encode numbers in a non-verbal quantity format. Subtypes of dyscalculia can be explained by lesions disproportionately affecting only one of these networks.  (+info)

Smoking and symbolism: children, communication and cigarettes. (2/111)

Health promotion, with its concern with empowerment and autonomy, must recognize the agency of its target population. Based on 85 in-depth interviews with 10- to 11-year-old children throughout Northern Ireland, this paper argues that it is necessary to focus on the social relations of children if we are to understand and prevent childhood smoking. Addressing the complex issue of childhood agency, it is argued that regardless of various restrictions to their choices, children can act intentionally in constructing their identities. Instead of viewing the smoking children as communicating with the adult world, we focus on smoking as negotiation of status within the children's culture. Such negotiations utilize symbolism derived from and shared with the 'adult world'. It is important that those analyzing children's lives understand children's ideas and behaviour on their own terms. We must make sure that the very concepts in which the children's experiences are put are appropriate ones. It is suggested that the metaphor 'rite of passage' and terminology such as peer 'pressure' versus adult 'influence', commonly used to analyse the children's smoking behaviour, may actually conceal important aspects of childhood agency.  (+info)

Increasing motorist compliance and caution at stop signs. (3/111)

This study evaluated strategies to improve motorist compliance and caution at three stop-sign-controlled intersections with a history of motor vehicle crashes. The primary intervention was a light-emitting diode (LED) sign that featured animated eyes scanning left and right to prompt drivers to look left and right for approaching traffic. Data were scored from videotape on the percentage of drivers coming to a complete stop and the percentage of drivers looking right before entering the intersection. Observational data were collected on the percentage of right-angle conflicts (defined as braking suddenly or swerving from the path to avoid an intersection crash). The introduction of the LED sign according to a multiple baseline across the three intersections was associated with an increase in the percentage of vehicles coming to a complete stop at all three intersections and a small increase in the percentage of drivers looking right before entering the intersections. Conflicts between vehicles on the major and minor road were also reduced following the introduction of the animated eyes prompt.  (+info)

White coat ceremonies: a second opinion. (4/111)

A "white coat" ceremony functions as a rite of passage for students entering medical school. This comment provides a second option in response to the earlier, more enthusiastic, discussion of the ceremony by Raanan Gillon. While these ceremonies may serve important sociological functions, they raise three serious problems: whether the professional oath or "affirmation of professional commitment" taken in this setting has any legitimacy, how a sponsor of such a ceremony would know which oath or affirmation to administer, and what the moral implications of this "bonding process" are. I argue that the initiation oath is morally meaningless if students are not aware of its content in advance, that different students ought to commit to different oaths, and that bonding of students to the medical profession necessarily separates them from identification with lay people who will be their patients.  (+info)

Tobacco sponsorship of Formula One and CART auto racing: tobacco brand exposure and enhanced symbolic imagery through co-sponsors' third party advertising. (5/111)

Through third party advertising of events such as Formula One and CART auto racing, tobacco brand names continue to attain visibility to a vast audience.  (+info)

Coding of cognitive magnitude: compressed scaling of numerical information in the primate prefrontal cortex. (6/111)

Whether cognitive representations are better conceived as language-based, symbolic representations or perceptually related, analog representations is a subject of debate. If cognitive processes parallel perceptual processes, then fundamental psychophysical laws should hold for each. To test this, we analyzed both behavioral and neuronal representations of numerosity in the prefrontal cortex of rhesus monkeys. The data were best described by a nonlinearly compressed scaling of numerical information, as postulated by the Weber-Fechner law or Stevens' law for psychophysical/sensory magnitudes. This nonlinear compression was observed on the neural level during the acquisition phase of the task and maintained through the memory phase with no further compression. These results suggest that certain cognitive and perceptual/sensory representations share the same fundamental mechanisms and neural coding schemes.  (+info)

Zebras in Russia! Where next? (7/111)

The zebra may seem an odd choice as a brand image for a new cigarette in Russia, but subtle tobacco marketing forces are, as always, at work.  (+info)

Abstraction in perceptual symbol systems. (8/111)

After reviewing six senses of abstraction, this article focuses on abstractions that take the form of summary representations. Three central properties of these abstractions are established: ( i ) type-token interpretation; (ii) structured representation; and (iii) dynamic realization. Traditional theories of representation handle interpretation and structure well but are not sufficiently dynamical. Conversely, connectionist theories are exquisitely dynamic but have problems with structure. Perceptual symbol systems offer an approach that implements all three properties naturally. Within this framework, a loose collection of property and relation simulators develops to represent abstractions. Type-token interpretation results from binding a property simulator to a region of a perceived or simulated category member. Structured representation results from binding a configuration of property and relation simulators to multiple regions in an integrated manner. Dynamic realization results from applying different subsets of property and relation simulators to category members on different occasions. From this standpoint, there are no permanent or complete abstractions of a category in memory. Instead, abstraction is the skill to construct temporary online interpretations of a category's members. Although an infinite number of abstractions are possible, attractors develop for habitual approaches to interpretation. This approach provides new ways of thinking about abstraction phenomena in categorization, inference, background knowledge and learning.  (+info)