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PubMed2003

Neural modeling in cerebral dynamics.

For many years our current conception of neural modeling at cortical level has been marked by three convictions: (i) the representational, explanatory, and predictive capabilities of a model are always limited by the mathematical nature of the formal tools used in its formulation. The external observer in fact injects the additional knowledge, apparently resident in the model. (ii) The analogical and logical languages (and consequently, the neurophysiological data which serves as their basis) are not sufficient to describe, model and predict the most genuine aspects of the cortical determined behavior. (iii) We need new conceptual and formal tools capable of representing cooperative processes (not only physical interactions) in cerebral dynamics. In this paper, we use the neuropsychological findings on the residual function after traumatic and surgical lesions in animals and men, to think about the sort of requirements that are necessary to build these formal tools adequate to model neural information processing at cortical level. If we search for inspiration in the field of computation, we arrive to the conjecture that the cerebral dynamics is a dynamics of neurophysiological symbols and, consequently, we need a set of descriptions at an intermediate level (neural assemblies "programming"), in a similar way as we use programming languages at an intermediate level (the symbol level) between the physical machine and the knowledge level descriptions, in the sense of Newell and Marr.

Animals↗

PubMed1990

A historical perspective on recent studies of social learning about foods by Norway rats.

Early naturalists explained field observations of social influences on animal learning in terms of spoken language, deliberate tuition of one animal by another, or intentional imitation. During the first half of the present century, experimental psychologists analyzed instances of social learning by animals in laboratory tasks as special cases of operant or classical conditioning. Neither of these traditional approaches provided much insight into the complex processes that often support animal social learning. By combining ethological focus on social learning as it occurs in natural habitat with analytical techniques developed in the psychological laboratory, contemporary researchers have made considerable progress in describing the many ways in which social interactions influence behavioural development in animals. The author's investigations of social influences on food selection by Norway rats provide one example of such an ethopsychological approach to the study of animal social learning.

Animal Communication↗

PubMed1988

Screening for fetal and genetic abnormality: social and ethical issues.

In answer to questions raised by practitioners, an ethics of genetic screening is located in a tension between liberty and responsibility in three respects: (1) to nature and biological processes; (2) to the disposal of human life; and (3) to the relation of persons to society. Under (1), the obligation to pursue research, fundamental as well as applied, is affirmed, offering the benefit of economy with fetal life, but requiring discrimination between the beneficial, the trivial, and the bizarre. Under (2) the abortion question, when relevant to diagnosed abnormality, is discussed, not in the language of conflicting rights, but of the relation of duties to interests. Under (3) the familial and social dimensions of screening raise questions of the disclosure of information and the keeping or extending of confidences. Last comes the value placed on truth in two related areas of developing practice. In infertility treatment, the donors of gametes are required to remain anonymous. Gene tracing through families requires for its effectiveness some correspondence between assumed identity and genetic identity. This conflict of social policies should be resolved.

Congenital Abnormalities↗

PubMed2005

An ecological framework for cancer communication: implications for research.

The field of cancer communication has undergone a major revolution as a result of the Internet. As recently as the early 1990s, face-to-face, print, and the telephone were the dominant methods of communication between health professionals and individuals in support of the prevention and treatment of cancer. Computer-supported interactive media existed, but this usually required sophisticated computer and video platforms that limited availability. The introduction of point-and-click interfaces for the Internet dramatically improved the ability of non-expert computer users to obtain and publish information electronically on the Web. Demand for Web access has driven computer sales for the home setting and improved the availability, capability, and affordability of desktop computers. New advances in information and computing technologies will lead to similarly dramatic changes in the affordability and accessibility of computers. Computers will move from the desktop into the environment and onto the body. Computers are becoming smaller, faster, more sophisticated, more responsive, less expensive, and--essentially--ubiquitous. Computers are evolving into much more than desktop communication devices. New computers include sensing, monitoring, geospatial tracking, just-in-time knowledge presentation, and a host of other information processes. The challenge for cancer communication researchers is to acknowledge the expanded capability of the Web and to move beyond the approaches to health promotion, behavior change, and communication that emerged during an era when language- and image-based interpersonal and mass communication strategies predominated. Ecological theory has been advanced since the early 1900s to explain the highly complex relationships among individuals, society, organizations, the built and natural environments, and personal and population health and well-being. This paper provides background on ecological theory, advances an Ecological Model of Internet-Based Cancer Communication intended to broaden the vision of potential uses of the Internet for cancer communication, and provides some examples of how such a model might inform future research and development in cancer communication.

Communication↗

PubMed2001

Cognitive processing in literate and illiterate subjects: a review of some recent behavioral and functional neuroimaging data.

The study of illiterate subjects, which for specific socio-cultural reasons did not have the opportunity to acquire basic reading and writing skills, represents one approach to study the interaction between neurobiological and cultural factors in cognitive development and the functional organization of the human brain. In addition the naturally occurring illiteracy may serve as a model for studying the influence of alphabetic orthography on auditory-verbal language. In this paper we have reviewed some recent behavioral and functional neuroimaging data indicating that learning an alphabetic written language modulates the auditory-verbal language system in a non-trivial way and provided support for the hypothesis that the functional architecture of the brain is modulated by literacy. We have also indicated that the effects of literacy and formal schooling is not limited to language related skills but appears to affect also other cognitive domains. In particular, we indicate that formal schooling influences 2D but not 3D visual naming skills. We have also pointed to the importance of using ecologically relevant tasks when comparing literate and illiterate subjects. We also demonstrate the applicability of a network approach in elucidating differences in the functional organization of the brain between groups. The strength of such an approach is the ability to study patterns of interactions between functionally specialized brain regions and the possibility to compare such patterns of brain interactions between groups or functional states. This complements the more commonly used activation approach to functional neuroimaging data, which characterize functionally specialized regions, and provides important data characterizing the functional interactions between these regions.

Aged↗

PubMed2004

Gender and lexical access in Bulgarian.

Two procedures were used to explore the effects of semantic and grammatical gender on the recognition and processing of Bulgarian nouns, in relation to other factors that are known to affect lexical access. This study in a three-gender language was modeled on previous work in Italian, a two-gender language (Bates, Devescovi, Pizzamiglio, D'Amico, & Hernandez, 1995). Words were presented auditorily in randomized lists in two tasks: (1) repeat the word as quickly as possible and (2) determine the grammatical gender of the noun as soon as possible and indicate the decision by pressing a button. Reaction times in both tasks were influenced by phonological factors, word frequency, and irregularity of gender marking, but semantic and grammatical gender affected only gender monitoring. The significant contribution of semantic gender to processing in Bulgarian contrasts with previous findings for Italian. Also, we obtained an interaction between sex of the subject and noun gender, reflecting a bias toward one's own grammatical gender "counterpart" (especially for females). Reanalysis of the prior study in Italian showed a similar interaction but confirmed no effects of the semantic gender of the noun, suggesting that these two natural gender effects can dissociate. Possible reasons for cross-linguistic differences are discussed, with implications for comparative studies of gender and lexical access.

Adolescent↗

PubMed2005

Comparison of continuous overt speech fMRI using BOLD and arterial spin labeling.

Overt speech production in functional magnetic resonance imaging (fMRI) studies is often associated with imaging artifacts, attributable to both movement and susceptibility. Various image-processing methods have been proposed to remove these artifacts from the data but none of these methods has been shown to work with continuous overt speech, at least over periods greater than 3 s. In this study natural, continuous, overt sentence production was evaluated in normal volunteers using both arterial spin labeling (ASL) and conventional echoplanar blood oxygenation level-dependent (BOLD) imaging sequences on the same 1.5-T scanner. We found a high congruency between activation results obtained with ASL and the de facto gold standard in overt language production imaging, positron emission tomography (PET). No task-related artifacts were found in the ASL study. However, the BOLD data showed artifacts that appeared as large bilateral false-positive temporopolar activations; percent signal change estimated in these regions showed signal increases and temporal dynamics that were incongruent with typical BOLD activations. These artifacts were not distributed uniformly, but were aligned at the frontotemporal base, close to the oropharynx. The calculated head movement parameters for overt speech blocks were within the range of the rest blocks, indicating that head movement is unlikely the reason for the artifact. We conclude that ASL is not influenced by overt speech artifacts, whereas BOLD showed significant susceptibility artifacts, especially in the opercular and insular regions, where activation would be expected. ASL may prove to be the method of choice for fMRI investigations of continuous overt speech.

Adult↗

PubMed2000

Neurophysiologic correlates of cross-language phonetic perception.

This study examined neurophysiologic correlates of the perception of native and nonnative phonetic categories. Behavioral and electrophysiologic responses were obtained from Hindi and English listeners in response to a stimulus continuum of naturally produced, bilabial CV stimuli that differed in VOT from -90 to 0 ms. These speech sounds constitute phonemically relevant categories in Hindi but not in English. As expected, the native Hindi listeners identified the stimuli as belonging to two distinct phonetic categories (/ba/ and /pa/) and were easily able to discriminate a stimulus pair across these categories. On the other hand, English listeners discriminated the same stimulus pair at a chance level. In the electrophysiologic experiment N1 and MMN cortical evoked potentials (considered neurophysiologic indices of stimulus processing) were measured. The changes in N1 latency which reflected the duration of pre-voicing across the stimulus continuum were not significantly different for Hindi and English listeners. On the other hand, in response to the /ba/-/pa/ stimulus contrast, a robust MMN was seen only in Hindi listeners and not in English listeners. These results suggest that neurophysiologic levels of stimulus processing reflected by the MMN and N1 are differentially altered by linguistic experience.

Cerebral Cortex↗

PubMed1988

Prolog-based system for nursing staff scheduling implemented on a personal computer.

An approach to the problem of nursing staff scheduling in a hospital is presented. For scheduling nurses, a variety of requirements with varied levels of significance has to be taken into account simultaneously. Because of the nature of the problem, where it is difficult to define what is the optimal solution in a strict sense, we aimed at automating scheduling by following the manual method in a faithful manner. A system for nurse scheduling has been implemented on a personal computer using Prolog. It determines favorable shift assignments on a day-to-day basis, referring to the information accumulated in the data base. In Prolog, various requirements can be expressed with relative ease, and the process of the manual method can be incorporated into the system in a natural way. The computer simulation has been conducted to test the system performance, and the obtained results demonstrated the validity of the approach.

Management Information Systems↗

PubMed1995

The immune self: a selectionist theory of recognition, learning, and remembering within the immune system.

In this paper, I have briefly explored metaphors shared by the immune and nervous systems and shown that this exercise can lead to the elucidation of common principles of organization, as well as to predictions concerning how the immune system functions. Metaphor itself undoubtedly reflects the way in which we categorize and retrieve information 44], so it is not surprising that the deep processes of language tend to sample information from related data categories. Although the nervous and immune systems are obviously not the same and metaphors are indeed just that, my primary goal has been to suggest that by virtue of their having evolved in parallel over millions of years, the nervous and immune systems currently use the same archetypal principles and strategies to address related challenges in information processing and retrieval. Ultimately, nature is conservative. One need only look at a tree, a river, the airways, or the vascular bed in order to see how a fractal pattern of repetitive dichotomous branching has been used by each, in order to optimize the transport of fluids over large distances [45]. While each system has had to adopt different materials in order to solve the problem, the shape of their solutions is remarkably alike. In the immune and nervous systems, the elements used to produce optimal functional responses are also quite different, but again the solutions have been achieved by comparable strategies. I am certain that these two great systems of information processing, each responding with vastly different kinetics, will prove to be far more integrally interdependent than has been previously recognized. For example, should a swift response by the immune system be required in an overwhelming invasion by microbial pathogens, the immune system may be able to cooperate with the rapidly reacting nervous system to rid the host of the invaders. In this regard, we have shown that the beta-adrenergic hormone epinephrine rapidly increases the traffic of memory T-cells to mucosal sites, presumably representing an immune component of the fight-or-flight response [46]. Neural evolution appears to have as its goal the development of more efficient information processing systems that lead to higher levels of consciousness. However, in modern times, technologic advances in information processing have rapidly outstripped the slower adaptations that can be made by evolution. In order to satisfy his compulsive quest for information, man has recently developed and recruited the aid of computers.(ABSTRACT TRUNCATED AT 400 WORDS)

Association Learning↗

PubMed2000

The interface between ADHD and language impairment: an examination of language, achievement, and cognitive processing.

Language impairments are commonly observed among children referred for psychiatric services. The most frequent psychiatric diagnosis of children with language impairment (LI) is Attention Deficit Hyperactivity Disorder (ADHD). It is not clear whether there are differences between children with ADHD and comorbid LI and children with other psychiatric disorders who are also comorbid for LI. In the present study the language, achievement, and cognitive processing characteristics of 166 psychiatrically referred 7-14-year-old children were examined using a 2 x 2 (ADHD, LI) design to examine four groups: children with ADHD + LI, children with ADHD who have normally developing language, children with psychiatric diagnoses other than ADHD with a language impairment (OPD + LI) or without a LI (OPD). Results indicated that children with LI were at the most disadvantage regardless of the nature of the psychiatric diagnosis. Contrary to prediction, working memory measures, used to tap the core cognitive deficit of ADHD in executive functions, were more closely associated with LI than with ADHD. It was concluded that caution must be exercised in attributing to children with ADHD what might be a reflection of problems for children with language impairment generally. As most therapies are verbally based it is notable that language competence is rarely evaluated systematically before such therapies are undertaken.

Achievement↗

PubMedDate not supplied

[August Weismann's concept of germ plasma as the basic reason for the inadequacy of neo-Darwinism].

Neo-Darwinism is a result of synthesis of Darwinian concept of natural selection with Weismannian concept of germ plasma. The concept of germ plasma is based on a hypothesis that phenotypic traits are completely determined by genes. Hence, neo-Darwinism describes evolution as a process of alternation of gene frequencies under the effect of natural selection. This is an inadequate approach to the study of evolution. In the course of evolution, genes change their functions, whereas phenotypic characters change their corresponding genes. As a result, every step of evolutionary transformation changes the structure of phenotype-to-genotype correspondence. Therefore, phenotypic evolution cannot be described in genetic terms, the same as to human languages cannot be translated one into another whenever the meaning of words is constantly changing. Consequently, Weismannian germ-plasma concept adequately describes the relation of characters to genes only during stasis, but is inapplicable to evolution.

Animals↗

PubMed2005

Cerebral asymmetry in children when reading Chinese characters.

This study examined cerebral asymmetry, especially in the hierarchical visual system, when reading Chinese characters. Twelve right-handed Chinese children (mean age = 11.6 years) were scanned while performing semantic and phonological tasks. Strong leftward asymmetry was found in the left inferior frontal cortex (BA44/45/47), the parietal lobule (BA40), and the cingulate cortex (BA24/32). In the visual system, we found significant left-hemispheric dominance in the fusiform cortex (BA19/37), but no asymmetry was found in the primary visual cortex (BA17/18). The differential results for the primary visual cortex versus high-order visual cortex (i.e., the fusiform cortex) are discussed in terms of the contribution of the logographic nature of Chinese characters to the asymmetry pattern in the hierarchical visual system.

Brain Mapping↗

PubMed2002

Finding UMLS Metathesaurus concepts in MEDLINE.

The entire collection of 11.5 million MEDLINE abstracts was processed to extract 549 million noun phrases using a shallow syntactic parser. English language strings in the 2002 and 2001 releases of the UMLS Metathesaurus were then matched against these phrases using flexible matching techniques. 34% of the Metathesaurus names (occurring in 30% of the concepts) were found in the titles and abstracts of articles in the literature. The matching concepts are fairly evenly chemical and non-chemical in nature and span a wide spectrum of semantic types. This paper details the approach taken and the results of the analysis.

MEDLINE↗

PubMed2006

Context-sensitive neural responses to conflict resolution: electrophysiological evidence from subject-object ambiguities in language comprehension.

Reanalysis in language comprehension provides a window on how superficially similar processes of conflict resolution may differ depending on the context in which they are initiated. Thus, previous ERP studies have shown that reanalyses towards object-initial orders in German sentences with dative-active verbs (e.g., folgen, 'to follow') engender N400 effects, while reanalyses with accusative verbs (e.g., besuchen, 'to visit') elicit P600 effects. This difference appears surprising since these two verb classes are both associated with a subject-initial base order. The present paper reports two ERP experiments designed to shed further light on the nature of the conflict resolution processes involved in each case by examining structures in which word order disambiguation is separated from verb class disambiguation. Experiment 1 contrasted dative-active verbs with accusative verbs, while Experiment 2 compared dative-active and dative object-experiencer verbs (which are associated with an object-initial base order). Our results show that the reanalysis pattern for dative-active constructions is context-dependent: when verb class disambiguation precedes word order disambiguation, an N400-P600 pattern results. By contrast, the reanalysis patterns for the other two verb types are context independent: object-experiencer verbs invariably show an N400 and accusative verbs invariably show a P600. We argue that (a) the N400 is a general marker of reanalysis in dative sentences, reflecting an argument reindexation, while (b) the P600 in accusative sentences reflects a structural recomputation. The variable pattern for dative-active sentences reflects the (in)applicability of "good-enough" representations during conflict resolution in garden path sentences.

Adult↗

PubMed2006

Skin and hair pigmentation variation in Island Melanesia.

Skin and hair pigmentation are two of the most easily visible examples of human phenotypic variation. Selection-based explanations for pigmentation variation in humans have focused on the relationship between melanin and ultraviolet radiation, which is largely dependent on latitude. In this study, skin and hair pigmentation were measured as the melanin (M) index, using narrow-band reflectance spectroscopy for 1,135 individuals from Island Melanesia. Overall, the results show remarkable pigmentation variation, given the small geographic region surveyed. This variation is discussed in terms of differences between males and females, among islands, and among neighborhoods within those islands. The relationship of pigmentation to age, latitude, and longitude is also examined. We found that male skin pigmentation was significantly darker than females in 5 of 6 islands examined. Hair pigmentation showed a negative, but weak, correlation with age, while skin pigmentation showed a positive, but also weak, correlation with age. Skin and hair pigmentation varied significantly between islands as well as between neighborhoods within those islands. Bougainvilleans showed significantly darker skin than individuals from any other island considered, and are darker than a previously described African-American population. These findings are discussed in relation to prevailing hypotheses about the role of natural selection in shaping pigmentation variation in the human species, as well as the role of demographic processes such as admixture and drift in Island Melanesia.

Adult↗

PubMed1992

The access and processing of familiar idioms by brain-damaged and normally aging adults.

Idiom interpretation tasks are routinely used in the clinical evaluation of adults with brain damage, and idiom processing has received increasing attention in the psycholinguistic literature. Clinical evidence suggests that adults with unilateral right-hemisphere damage (RHD) are insensitive to nonliteral meanings conveyed by idiomatic expressions and other figurative forms. However, this portrayal is derived from their terminal responses to tasks that reflect multiple aspects of mental operations (off-line measures), obscuring the source of poor performance. This study used an on-line word-monitoring task to assess RHD, left-hemisphere-damaged, and normally aging adults' implicit knowledge of familiar idiomatic expressions. Brain-damaged subjects performed similarly to normal controls on this task, even though the clinical subjects fared poorly by comparison on an off-line idiom definition measure. These results suggest that adults with unilateral brain damage can activate and retrieve familiar idiomatic forms, and that their idiom-interpretation deficits most likely reflect impairment at some later stage of information processing. Further, error analysis of idiom-definition performance did not support the customary characterization of RHD adults as excessively literal responders. The paper discusses clinical implications of the nature and use of idiom interpretation tasks.

Aged↗

PubMed1990

Some constraints on functionally disordered phonologies: phonetic inventories and phonotactics.

The phonological systems of 40 functional misarticulators, ages 40 to 80 months were examined in terms of the nature and variation of phonetic inventories and phonotactic constraints. It was found that these properties of disordered systems were governed by severe constraints that yielded a typological characterization of such systems along with associated implicational laws. The principles governing disordered systems were also found to parallel closely the principles governing normal first language acquisition. The evidence suggests that at least these properties of disordered systems represent delays in the normal acquisition process and are not otherwise deviant. The assessment and treatment of functional disorders along with the projection of learning patterns can thus appeal to principles governing such phonological systems.

Articulation Disorders↗