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PubMed2005

Prosody-driven sentence processing: an event-related brain potential study.

Four experiments systematically investigating the brain's response to the perception of sentences containing differing amounts of linguistic information are presented. Spoken language generally provides various levels of information for the interpretation of the incoming speech stream. Here, we focus on the processing of prosodic phrasing, especially on its interplay with phonemic, semantic, and syntactic information. An event-related brain potential (ERP) paradigm was chosen to record the on-line responses to the processing of sentences containing major prosodic boundaries. For the perception of these prosodic boundaries, the so-called closure positive shift (CPS) has been manifested as a reliable and replicable ERP component. It has mainly been shown to correlate to major intonational phrasing in spoken language. However, to define this component as exclusively relying on the prosodic information in the speech stream, it is necessary to systematically reduce the linguistic content of the stimulus material. This was done by creating quasi-natural sentence material with decreasing semantic, syntactic, and phonemic information (i. e., jabberwocky sentences, in which all content words were replaced by meaningless words; pseudoword sentences, in which all function and all content words are replaced by meaningless words; and delexicalized sentences, hummed intonation contour of a sentence removing all segmental content). The finding that a CPS was identified in all sentence types in correlation to the perception of their major intonational boundaries clearly indicates that this effect is driven purely by prosody.

Acoustic Stimulation↗

PubMed2002

The contribution of visual areas to speech comprehension: a PET study in cochlear implants patients and normal-hearing subjects.

Early visual cortex can be recruited by meaningful sounds in the absence of visual information. This occurs in particular in cochlear implant (CI) patients whose dependency on visual cues in speech comprehension is increased. Such cross-modal interaction mirrors the response of early auditory cortex to mouth movements (speech reading) and may reflect the natural expectancy of the visual counterpart of sounds, lip movements. Here we pursue the hypothesis that visual activations occur specifically in response to meaningful sounds. We performed PET in both CI patients and controls, while subjects listened either to their native language or to a completely unknown language. A recruitment of early visual cortex, the left posterior inferior temporal gyrus (ITG) and the left superior parietal cortex was observed in both groups. While no further activation occurred in the group of normal-hearing subjects, CI patients additionally recruited the right perirhinal/fusiform and mid-fusiform, the right temporo-occipito-parietal (TOP) junction and the left inferior prefrontal cortex (LIPF, Broca's area). This study confirms a participation of visual cortical areas in semantic processing of speech sounds. Observation of early visual activation in normal-hearing subjects shows that auditory-to-visual cross-modal effects can also be recruited under natural hearing conditions. In cochlear implant patients, speech activates the mid-fusiform gyrus in the vicinity of the so-called face area. This suggests that specific cross-modal interaction involving advanced stages in the visual processing hierarchy develops after cochlear implantation and may be the correlate of increased usage of lip-reading.

Auditory Cortex↗

PubMed2004

The effects of motor neurone disease on language: further evidence.

It might sound surprising that Motor Neurone Disease (MND), regarded still by many as the very example of a neurodegenerative disease affecting selectively the motor system and sparing the sensory functions as well as cognition, can have a significant influence on language. In this article we hope to demonstrate that language dysfunction is not only a pronounced and well documented symptom in some MND patients but also that the study of language in MND can address interesting theoretical questions about the representation of language and conceptual knowledge in the brain. After a brief introduction delineating clinical and pathological features of the disease we discuss the evidence available in the literature for language dysfunction in MND. We then present linguistic data from our own study of seven patients with MND/dementia/aphasia syndrome focusing on the dissociation between noun and verb processing. To illustrate the clinical, neuropsychological and linguistic aspects of MND we describe in more detail the patient E.N., a pathologically confirmed case of MND/dementia. Finally, we attempt to characterise the nature of the linguistic impairment in MND in the light of current debates about the mechanisms underlying noun/verb dissociation.

Anomia↗

PubMed1999

Common model of evolution for living cell and central nervous system.

Both living cell and central nervous system can be treated as objects similar to artificial neural networks, actively studied now. One can see deep analogies between evolutionary processes in these systems, and correspondences can be established between some phenomena and objects. These are: genome vs. memory, gene vs. symbol, cell type vs. image, mitosis vs. sleep, organism vs. perception state, species vs. language, fertilization vs. attention, meiosis vs. paradoxal sleep. There is reason to study these correspondences on more technical level being based upon network nature of the living cell and nervous system.

Biological Evolution↗

PubMed2001

A study of abbreviations in the UMLS.

Abbreviations are widely used in medicine. The understanding of abbreviations is important for medical language processing and information retrieval systems. The Unified Medical Language System (UMLS) contains a large number of abbreviations. We hypothesized that extracting and studying the UMLS abbreviations can be helpful for understanding the characteristics of abbreviations in medicine. In this paper, we describe a method for extracting abbreviations from the UMLS. We evaluated the method and studied the ambiguous nature of the abbreviations. In addition, the coverage of the UMLS abbreviations in medical reports was studied. Using our method, we extracted 163,666 unique (abbreviation, full form) pairs from the UMLS with a precision of 97.5%, and a recall of 96%. The UMLS abbreviations were highly ambiguous: 33.1% of abbreviations with six characters or less had multiple meanings; the average number of different full forms for all abbreviations with six characters or less was 2.28. The coverage of the UMLS abbreviations in medical reports was over 66%.

Abbreviations as Topic↗

PubMed1997

A neuropsychological perspective on three schizophrenic patients with midline structural defects.

BACKGROUND: The relationship between midline structural defects and schizophrenia remains unclear, although a number of neuroradiological studies have reported an association between schizophrenia and a range of anomalies. METHOD: Three patients are reported, each diagnosed with schizophrenia and neuroradiological evidence of midline structural anomalies. MRI scans are reported in conjunction with performance over a range of neuropsychological tests designed to assess frontal and lateralised cognitive functions. RESULTS: Evidence of anterior dysfunction was present in all three cases, while on an individual basis patients displayed varying patterns of preserved and dysfunctional cognitive processing. CONCLUSION: The reported findings raise a number of interesting issues regarding the nature of hemispheric involvement in schizophrenia.

Adult↗

PubMed2003

Postmodern society and social networks: open and anticipation dialogues in network meetings.

Network therapy flourished in the U.S. during the 1970s, but has since dwindled there and begun to find new applications in Europe, especially in the Nordic countries. State social and healthcare systems, in developing deep vertical expertise, seems to build up a need for complementary horizontal expertise. The latest theories of sociology are used to analyze the need for networking, with the focus on language and dialogue as specific form. Two approaches developed in crisis service for psychotic patients (Open Dialogue) and in consultation for stuck cases in social care (Anticipation Dialogues), are dealt with. What becomes essential seems no longer to be the therapeutic method itself but the ability to see the polyphonic nature of clients' reality. In this respect, language--and dialogue as a specific form of being in language--as the focus of treatment, makes the practical forms of different approaches secondary.

Communication↗

PubMed2000

Hemispheric lateralization in an analysis of speech sounds. Left hemisphere dominance replicated in Japanese subjects.

Evoked magnetic responses to speech sounds [R. Näätänen, A. Lehtokoski, M. Lennes, M. Cheour, M. Huotilainen, A. Iivonen, M. Vainio, P. Alku, R.J. Ilmoniemi, A. Luuk, J. Allik, J. Sinkkonen and K. Alho, Language-specific phoneme representations revealed by electric and magnetic brain responses. Nature, 385 (1997) 432-434.] were recorded from 13 Japanese subjects (right-handed). Infrequently presented vowels ([o]) among repetitive vowels ([e]) elicited the magnetic counterpart of mismatch negativity, MMNm (Bilateral, nine subjects; Left hemisphere alone, three subjects; Right hemisphere alone, one subject). The estimated source of the MMNm was stronger in the left than in the right auditory cortex. The sources were located posteriorly in the left than in the right auditory cortex. These findings are consistent with the results obtained in Finnish [R. Näätänen, A. Lehtokoski, M. Lennes, M. Cheour, M. Huotilainen, A. Iivonen, M.Vainio, P.Alku, R.J. Ilmoniemi, A. Luuk, J. Allik, J. Sinkkonen and K. Alho, Language-specific phoneme representations revealed by electric and magnetic brain responses. Nature, 385 (1997) 432-434.][T. Rinne, K. Alho, P. Alku, M. Holi, J. Sinkkonen, J. Virtanen, O. Bertrand and R. Näätänen, Analysis of speech sounds is left-hemisphere predominant at 100-150 ms after sound onset. Neuroreport, 10 (1999) 1113-1117.] and English [K. Alho, J.F. Connolly, M. Cheour, A. Lehtokoski, M. Huotilainen, J. Virtanen, R. Aulanko and R.J. Ilmoniemi, Hemispheric lateralization in preattentive processing of speech sounds. Neurosci. Lett., 258 (1998) 9-12.] subjects. Instead of the P1m observed in Finnish [M. Tervaniemi, A. Kujala, K. Alho, J. Virtanen, R.J. Ilmoniemi and R. Näätänen, Functional specialization of the human auditory cortex in processing phonetic and musical sounds: A magnetoencephalographic (MEG) study. Neuroimage, 9 (1999) 330-336.] and English [K. Alho, J. F. Connolly, M. Cheour, A. Lehtokoski, M. Huotilainen, J. Virtanen, R. Aulanko and R.J. Ilmoniemi, Hemispheric lateralization in preattentive processing of speech sounds. Neurosci. Lett., 258 (1998) 9-12.] subjects, prior to the MMNm, M60, was elicited by both rare and frequent sounds. Both MMNm and M60 sources were posteriorly located in the left than the right hemisphere.

Adult↗

PubMed2002

DataServer: an infrastructure to support evidence-based radiology.

Following a requirements analysis for development of an information infrastructure supporting evidence-based radiology, the objective of this study was the development of a data gateway to support flexible access to the totality of a patient's electronic medical records through a single, uniform representation, regardless of the underlying data sources (eg, hospital information systems [HIS], radiology information systems [RIS], picture archiving and communication systems [PACS]). XML-based (eXtensible Markup Language) technologies were employed to create an application framework permitting querying of different clinical databases. The contents of different data sources were represented by using XML. On the basis of these representations, users can specify queries. The system transforms the XML queries into a query format understood by the specific databases, processes the query, and transforms the results back into an XML format. XML results can then be transformed in accordance to different data-formatting standards. Access to several different data sources, including HIS, RIS, and PACS, has been accomplished with this framework. The extensible nature of the XML data gateway enables data sources to be readily added. The framework also provides a means by which data can be systematically de-identified to protect patient confidentiality, thus supporting research endeavors.

Evidence-Based Medicine↗

PubMed2003

How the brain solves the binding problem for language: a neurocomputational model of syntactic processing.

Syntax is one of the components in the architecture of language processing that allows the listener/reader to bind single-word information into a unified interpretation of multiword utterances. This paper discusses ERP effects that have been observed in relation to syntactic processing. The fact that these effects differ from the semantic N400 indicates that the brain honors the distinction between semantic and syntactic binding operations. Two models of syntactic processing attempt to account for syntax-related ERP effects. One type of model is serial, with a first phase that is purely syntactic in nature (syntax-first model). The other type of model is parallel and assumes that information immediately guides the interpretation process once it becomes available. This is referred to as the immediacy model. ERP evidence is presented in support of the latter model. Next, an explicit computational model is proposed to explain the ERP data. This Unification Model assumes that syntactic frames are stored in memory and retrieved on the basis of the spoken or written word form input. The syntactic frames associated with the individual lexical items are unified by a dynamic binding process into a structural representation that spans the whole utterance. On the basis of a meta-analysis of imaging studies on syntax, it is argued that the left posterior inferior frontal cortex is involved in binding syntactic frames together, whereas the left superior temporal cortex is involved in retrieval of the syntactic frames stored in memory. Lesion data that support the involvement of this left frontotemporal network in syntactic processing are discussed.

Brain↗

PubMed2006

Assessing cognitive & motor performance in minimally invasive surgery (MIS) for training & tool design.

The objective of this paper is to present the development of a new modelling diagram (MCMD) to represent MIS procedures in terms of both motor and cognitive actions. Through observation and analysis of several laparoscopic cholecystectomy procedures and based on task analysis techniques, we created a diagram language composed of six primary symbols: processes, decisions, interrupt service routines (ISRs), options points and AND and OR gates. We then tested and refined them during 10 new cases until no further changes seemed necessary, we have since applied this approach to 6 laparoscopic colorectal surgeries and have found that no further symbols were necessary though the procedural representation was naturally different. This modelling diagram allowed us to represent both cognitive and motor performance aspects of surgical procedures in a unified framework and will in future allow us to assess motor performance on particular surgical tasks at particular points in the procedure (i.e., the surgical context).

Computer Simulation↗

PubMed1998

[The use of Cantonese pain descriptors among healthy young adults in Hong Kong].

BACKGROUND: The interpretation and expression of pain are closely related to an individual's social and cultural background. To convey messages on pain, language and words (pain descriptors) is particularly significant in assessment and evaluation of pain severity and its management. Therefore, the study of pain descriptors is crucial in clinical practice. METHODS: It was of exploratory-descriptive design. Samples were recruited by convenience. Data were collected by structured self-administered questionnaire. Data obtained included demographic information and pain descriptors used by the subjects in various pain conditions. Data were analyzed by descriptive statistics. Pain descriptors were categorized according to nature, process, intensity, aggravating factors, accompanying symptoms and behavioral manifestation. RESULTS: Total number of pain descriptors (in Cantonese) based on real pain experience was 3017, mean was 3 (n = 986). The commonest used descriptors was the nature of pain (41%). The intensity of pain constituted 20%. There was no significant difference in the number of pain descriptors between male and female. However, there was a significant difference between the type of pain descriptors used (Mfemale = 526, Mmale = 453, Z = -2.9729, p = 0.0029). There were also significant differences in the use of pain descriptors among the various age groups (X2 = 15.0157, df = 4, P = 0.0047) and educational levels (X2 = 11.2443, df = 4, P = 0.0240). The types of descriptors used increased with an increase in age and education levels. CONCLUSIONS: This exploratory-descriptive study explores the use of pain descriptors among Chinese young adults in Hong Kong. The result shows that female use more pain descriptors than male. The pain descriptors that female used are mostly of nature type. The similarities and differences in findings with those of the Ho's (1991) are compared.

Adolescent↗

PubMed1994

A neural network model of speech acquisition and motor equivalent speech production.

This article describes a neural network model that addresses the acquisition of speaking skills by infants and subsequent motor equivalent production of speech sounds. The model learns two mappings during a babbling phase. A phonetic-to-orosensory mapping specifies a vocal tract target for each speech sound; these targets take the form of convex regions in orosensory coordinates defining the shape of the vocal tract. The babbling process wherein these convex region targets are formed explains how an infant can learn phoneme-specific and language-specific limits on acceptable variability of articulator movements. The model also learns an orosensory-to-articulatory mapping wherein cells coding desired movement directions in orosensory space learn articulator movements that achieve these orosensory movement directions. The resulting mapping provides a natural explanation for the formation of coordinative structures. This mapping also makes efficient use of redundancy in the articulator system, thereby providing the model with motor equivalent capabilities. Simulations verify the model's ability to compensate for constraints or perturbations applied to the articulators automatically and without new learning and to explain contextual variability seen in human speech production.

Child↗

PubMed1989

Processing of visual syntax in a globally aphasic patient.

A globally aphasic patient was trained on a computerized visual communication system. His ability to comprehend reversible locative prepositional phrases after training was studied and compared with the performance of Broca's aphasics on a similar task. This patient's ability to generalize symbols for actions was also investigated. The results demonstrate our patient's capacity to master a formal visual syntax in the absence of natural language and illustrate how this capacity may be used successfully in a visual communication system. A problem in generalizing symbols for actions is demonstrated, suggesting that certain heuristic and cueing capabilities in the approach may be helpful.

Aphasia↗

PubMed1999

Syntactic priming in language production.

People have a tendency to repeat the types of sentences they use during language production. Recent experimental work has shown that this phenomenon is at least partly due to 'syntactic priming', whereby the act of processing an utterance with a particular form facilitates processing a subsequent utterance with the same or a related form. In this review, we first provide an overview of the evidence for syntactic priming. The review will then explore the implications of this research for three different areas of language theory: the possible functional significance of syntactic priming in coordinating speakers during dialogue, the mechanisms underlying sentence production, and the nature of linguistic representation.

Journal Article↗

PubMed2005

MMN to natural Arabic CV syllables: 2 - cross language study.

Mismatch negativity response parameters; latency, amplitude, and duration - to natural Arabic and natural English CV syllables - were obtained from normal-hearing adult Egyptians, in two experiments. In the first experiment, MMN was obtained in response to English CV syllable paradigms (Ba-Wa) and (Ga-Da) differing in formant duration and start of third formant, respectively. In the second experiment, MMN response for Arabic paradigm (Baa-Waa), English paradigm (Ba-Wa), and for Arabic-English paradigm (Waa-Wa) was obtained. Results revealed that the three levels of speech representation; acoustic, phonetic and phonologic could be probed preattentatively by MMN. The acoustic properties of speech signal are processed earlier than the phonetic and phonologic properties.

Adolescent↗

PubMed2002

Motivational views of reinforcement: implications for understanding the behavioral functions of nucleus accumbens dopamine.

Although the Skinnerian 'Empirical Law of Effect' does not directly consider the fundamental properties of stimuli that enable them to act as reinforcers, such considerations are critical for determining if nucleus accumbens dopamine systems mediate reinforcement processes. Researchers who have attempted to identify the critical characteristics of reinforcing stimuli or activities have generally arrived at an emphasis upon motivational factors. A thorough review of the behavioral literature indicates that, across several different investigators offering a multitude of theoretical approaches, motivation is seen by many as being fundamental to the process of reinforcement. The reinforcer has been described as a goal, a commodity, an incentive, or a stimulus that is being approached, self-administered, attained or preserved. Reinforcers also have been described as activities that are preferred, deprived or in some way being regulated. It is evident that this 'motivational' or 'regulatory' view of reinforcement has had enormous influence over the hypothesis that DA directly mediates 'reward' or 'reinforcement' processes. Indeed, proponents of the DA/reward hypothesis regularly cite motivational theorists and employ their language. Nevertheless, considerable evidence indicates that low/moderate doses of DA antagonists, and depletions of DA in nucleus accumbens, can suppress instrumental responding for food while, at the same time, these conditions leave fundamental aspects of reinforcement (i.e. primary or unconditioned reinforcement; primary motivation or primary incentive properties of natural reinforcers) intact. Several complex features of the literature on dopaminergic involvement in reinforcement are examined below, and it is argued that the assertions that DA mediates 'reward' or 'reinforcement' are inaccurate and grossly oversimplified. Thus, it appears as though it is no longer tenable to assert that drugs of abuse are simply turning on the brain's natural 'reward system'. In relation to the hypothesis that DA systems are involved in 'wanting', but not 'liking', it is suggested in the present review that 'wanting' has both directional aspects (e.g. appetite to consume food) and activational aspects (e.g. activation for initiating and sustaining instrumental actions; tendency to work for food). The present paper reviews findings in support of the hypothesis that low doses of DA antagonists and accumbens DA depletions do not impair appetite to consume food, but do impair activational aspects of motivation. This suggestion is consistent with the studies showing that low doses of DA antagonists and accumbens DA depletions alter the relative allocation of instrumental responses, making the animals less likely to engage in instrumental responses that have a high degree of work-related response costs. In addition, this observation is consistent with studies demonstrating that accumbens DA depletions make rats highly sensitive to ratio requirements on operant schedules. Although accumbens DA is not seen as directly mediating appetite to consume food, principles of behavioral economics indicate that accumbens DA could be involved in the elasticity of demand for food in terms of the tendency to pay work-related response costs. Future research must focus upon how specific aspects of task requirements (i.e. ratio requirements, intermittence of reinforcement, temporal features of response requirements, dependence upon conditioned stimuli) interact with the effects of accumbens DA depletions, and which particular factors determine sensitivity to the effects of DA antagonism or depletion.

Animals↗

PubMed2001

Numeric simulation of plant signaling networks.

Plants have evolved an intricate signaling apparatus that integrates relevant information and allows an optimal response to environmental conditions. For instance, the coordination of defense responses against pathogens involves sophisticated molecular detection and communication systems. Multiple protection strategies may be deployed differentially by the plant according to the nature of the invading organism. These responses are also influenced by the environment, metabolism, and developmental stage of the plant. Though the cellular signaling processes traditionally have been described as linear sequences of events, it is now evident that they may be represented more accurately as network-like structures. The emerging paradigm can be represented readily with the use of Boolean language. This digital (numeric) formalism allows an accurate qualitative description of the signal transduction processes, and a dynamic representation through computer simulation. Moreover, it provides the required power to process the increasing amount of information emerging from the fields of genomics and proteomics, and from the use of new technologies such as microarray analysis. In this review, we have used the Boolean language to represent and analyze part of the signaling network of disease resistance in Arabidopsis.

Algorithms↗