A syntactic specialization for Broca's area.
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Despite numerous aphasia and functional imaging studies, the exact correlation between cortical language areas and subcomponents of the linguistic system has not been established. Here, we used functional MRI to identify cortical areas specifically involved in syntactic processing. An experimental design contrasted sentences containing grammatical errors with sentences containing spelling errors. The ungrammatical sentences produced more activation in cortical language areas than did the sentences with spelling errors, and the difference in activation was significantly greater in Broca's area than in Wernicke's area or in the angular gyrus/supramarginal gyrus. The present findings provide direct evidence of a syntactic specialization for Broca's area and establish the existence of distinct modules for our knowledge of language. (+info)
The size distribution of conspecific populations: the peoples of New Guinea.
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The size distribution of the language populations in New Guinea, which represent over 15% of the world's languages, is analysed using models analogous to the resource division models of species abundance distribution in ecological communities. A model distribution of resource segments reflecting population size is created by repeated selection of an existing resource segment and its division into two. We found that any dependency of the selection probability on the size of the segment generated negatively skewed abundance distributions after log transformation. Asymmetric segment division further exacerbated the negative skewness. Size-independent selection produced lognormal abundance distributions, irrespective of the segment division method. Size-dependent selection and asymmetric division were deemed reasonable assumptions since large language populations are more likely to generate isolates, which develop into new populations, than small ones, and these isolates are likely to be small relative to the progenitor population. A negatively skewed distribution of the log-transformed population sizes was therefore expected. However, the observed distributions were lognormal, scale invariant for areas containing between 100 and over 1000 language populations. The dynamics of language differentiation, as reflected by the models, may therefore be unimportant relative to the effect of variable growth rates among populations. All lognormal distributions from resource division models had a higher variance than the observed one, where half of the 1053 populations had between 350 and 3000 individuals. The possible mechanisms maintaining such a low variance around a modal population size of 1000 are discussed. (+info)
Self-monitoring of blood glucose: language and financial barriers in a managed care population with diabetes.
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OBJECTIVE: Self-monitoring of blood glucose (SMBG) is a cornerstone of diabetes care, but little is known about barriers to this self-care practice. RESEARCH DESIGN AND METHODS: This cross-sectional study examines SMBG practice patterns and barriers in 44,181 adults with pharmacologically treated diabetes from the Kaiser Permanente Northern California Region who responded to a health survey (83% response rate). The primary outcome is self-reported frequency of SMBG. RESULTS: Although most patients reported some level of SMBG monitoring, 60% of those with type 1 diabetes and 67% of those with type 2 diabetes reported practicing SMBG less frequently than recommended by the American Diabetes Association (three to four times daily for type 1 diabetes, and once daily for type 2 diabetes treated pharmacologically). Significant independent predictors of nonadherent practice of SMBG included longer time since diagnosis, less intensive therapy, male sex, age, belonging to an ethnic minority, having a lower education and neighborhood income, difficulty communicating in English, higher out-of-pocket costs for glucometer strips (especially for subjects with lower incomes), smoking, and excessive alcohol consumption. CONCLUSIONS: Considerable gaps persist between actual and recommended SMBG practices in this large managed care organization. A somewhat reduced SMBG frequency in subjects with linguistic barriers, some ethnic minorities, and subjects with lower education levels suggests the potential for targeted, culturally sensitive, multilingual health education. The somewhat lower frequency of SMBG among subjects paying higher out-of-pocket expenditures for strips suggests that removal of financial barriers by providing more comprehensive coverage for these costs may enhance adherence to recommendations for SMBG. (+info)
An event-related functional MRI study of the stroop color word interference task.
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In this study we have attempted to define the neural circuits differentially activated by cognitive interference. We used event-related functional magnetic resonance imaging (fMRI) to identify areas of the brain that are activated by the Stroop word-color task in two experiments. In the first experiment, we used infrequent, incongruent colored word stimuli to elicit strong Stroop interference (the 'conventional Stroop' paradigm). In the second experiment, we used infrequent, congruent colored words (the 'inverse Stroop' paradigm) to confirm that the regions identified in the first experiment were in fact specifically related to the Stroop effect and not to nonspecific oddball effects associated with the use of infrequent stimuli. Performance of the conventional Stroop specifically activated the anterior cingulate, insula, premotor and inferior frontal regions. These activated regions in the current experiment are consistent with those activated in fMRI experiments that use a more traditional block design. Finally, analysis of the time course of fMRI signal changes demonstrated differential onset and offset of signal changes in these activated regions. The time course results suggest that the action of various brain areas can be temporally dissociated. (+info)
Declining immune function in children and adolescents with hemophilia and HIV infection: effects on neuropsychological performance. Hemophilia Growth and Development Study.
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OBJECTIVE: To determine whether declines in immune functioning are associated with changes in neuropsychological performance in children and adolescents with hemophilia who are infected with the human immunodeficiency virus (HIV). METHODS: Participants were 333 males with hemophilia, ages 6-19 years at entry. A baseline and four annual neuropsychological evaluations were given. A longitudinal growth curves analysis of data was performed to detect changes associated with declining immune function. The cohort was stratified into four groups: (1) HIV- (n = 126); (2) HIV+, average of first two and last two CD4 counts > or = 200, (n = 106; High CD4 group); (3) HIV+, average first two counts > or = 200, average last two counts < 200 (n = 41; CD4 Drop group); and (4) HIV+, average first two and last two counts < 200 (n = 60; Low CD4 group). RESULTS: There were significant differences among the four groups over time in nonverbal intelligence, perceptual/performance skills, nonverbal memory, academic achievement, and language. The Low CD4 group consistently showed the greatest decrement in performance. On measures showing a practice effect for repeated measurements, the Low CD4 group participants' scores remained stable over time, suggesting opposing effects of practice and HIV-related declines. Lowered academic performance relative to IQ was found in all groups. CONCLUSIONS: Declines in neuropsychological functioning are directly related to declines in immune functioning in HIV+ children, adolescents, and young adults with hemophilia. Hemophilia itself may be a risk factor for academic underachievement. (+info)
Language and thought: does grammar makes us smart?
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Many philosophers and psychologists believe that only people with rich language skills are capable of abstract reasoning. A man with a severe linguistic impairment poses a striking challenge to this view. (+info)
EDGAR: extraction of drugs, genes and relations from the biomedical literature.
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EDGAR (Extraction of Drugs, Genes and Relations) is a natural language processing system that extracts information about drugs and genes relevant to cancer from the biomedical literature. This automatically extracted information has remarkable potential to facilitate computational analysis in the molecular biology of cancer, and the technology is straightforwardly generalizable to many areas of biomedicine. This paper reports on the mechanisms for automatically generating such assertions and on a simple application, conceptual clustering of documents. The system uses a stochastic part of speech tagger, generates an underspecified syntactic parse and then uses semantic and pragmatic information to construct its assertions. The system builds on two important existing resources: the MEDLINE database of biomedical citations and abstracts and the Unified Medical Language System, which provides syntactic and semantic information about the terms found in biomedical abstracts. (+info)
An error limit for the evolution of language.
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On the evolutionary trajectory that led to human language there must have been a transition from a fairly limited to an essentially unlimited communication system. The structure of modern human languages reveals at least two steps that are required for such a transition: in all languages (i) a small number of phonemes are used to generate a large number of words; and (ii) a large number of words are used to a produce an unlimited number of sentences. The first (and simpler) step is the topic of the current paper. We study the evolution of communication in the presence of errors and show that this limits the number of objects (or concepts) that can be described by a simple communication system. The evolutionary optimum is achieved by using only a small number of signals to describe a few valuable concepts. Adding more signals does not increase the fitness of a language. This represents an error limit for the evolution of communication. We show that this error limit can be overcome by combining signals (phonemes) into words. The transition from an analogue to a digital system was a necessary step toward the evolution of human language. (+info)