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PubMed2006

Effects of acoustic distortion and semantic context on event-related potentials to spoken words.

This study examined the neurophysiological effects of acoustic degradation on auditory semantic processing. Event-related potentials were recorded to target words presented in a sentence context. Targets were semantically congruent or incongruent with the context, which was acoustically intact or low-pass filtered. In unaltered contexts, N400 amplitude was significantly greater for incongruent than congruent words. Filtering significantly reduced this effect, even though participants were highly accurate in interpreting the degraded stimuli, as shown by an anomaly detection task. This reduction in the N400 effect appeared to be driven by decreased N400 amplitudes over posterior electrode sites for incongruent targets. These results demonstrate that acoustic degradation influences the neural response to words in context by reducing the availability of semantic information in on-line sentence comprehension.

Acoustic Stimulation↗

PubMed2000

From autopoiesis to semantic closure.

This article addresses the question of providing an adequate mathematical formulation for the concepts of autopoiesis and closure under efficient cause. What is required is metaphorically equivalent to reducing the act of writing to a set of mathematical equations, habitually effected by a human mathematician, within the ongoing function of the system itself. This, in turn, raises the question of the relationship between autopoiesis and semantics. The hypothesis suggested is that whereas semantics clearly requires autopoiesis, it may be also be the case that autopoiesis itself can only be materially realized in a system that is characterized by a semantic dimension.

Humans↗

PubMed1983

The effect of memory impairment on verbal recognition scores and the marking of acoustic and semantic distractors.

A test of verbal recognition, yielding separate scores for semantic and acoustic distractor errors as well as a simple recognition score, successfully discriminated between various groups of brain-damaged, depressive, and normal subjects in a sequence predictable from their pathology. However, the profile of distractor errors was similar for all groups tested, with a consistent tendency for subjects to make more semantic errors than acoustic errors in all cases. It was concluded that the failure to find qualitative coding differences was probably a consequence of the procedure used and did not necessarily contradict previous findings that amnesics were less effective than normal subjects in coding semantically.

Amnesia↗

PubMed1980

Recognition of word associates in semantic paralexia.

This study examines the processing of word associates by a patient who makes semantic paralexic responses ir oral reading. His ability to extract semantic features from printed words was assessed using a task which involved the recognition of specific associates of printed words. He could recognize as many associate words as normal control patients, but was more likely to make a positive response to stimulus words unrelated to the target item. There was also a tendency to more readily accept same-category associates as being related to target words. It is suggested that semantic paralexic patients sometimes make inadequate 'checks' on related words which are activated when printed words are perceived, and possible retraining procedures are suggested which may improve their checking strategies.

Adult↗

PubMedDate not supplied

Evaluation of the clinical LOINC (Logical Observation Identifiers, Names, and Codes) semantic structure as a terminology model for standardized assessment measures.

OBJECTIVE: The purpose of this study was to test the adequacy of the Clinical LOINC (Logical Observation Identifiers, Names, and Codes) semantic structure as a terminology model for standardized assessment measures. METHODS: After extension of the definitions, 1, 096 items from 35 standardized assessment instruments were dissected into the elements of the Clinical LOINC semantic structure. An additional coder dissected at least one randomly selected item from each instrument. When multiple scale types occurred in a single instrument, a second coder dissected one randomly selected item representative of each scale type. RESULTS: The results support the adequacy of the Clinical LOINC semantic structure as a terminology model for standardized assessments. Using the revised definitions, the coders were able to dissect into the elements of Clinical LOINC all the standardized assessment items in the sample instruments. Percentage agreement for each element was as follows: component, 100 percent; property, 87.8 percent; timing, 82.9 percent; system/sample, 100 percent; scale, 92.6 percent; and method, 97.6 percent. DISCUSSION: This evaluation was an initial step toward the representation of standardized assessment items in a manner that facilitates data sharing and re-use. Further clarification of the definitions, especially those related to time and property, is required to improve inter-rater reliability and to harmonize the representations with similar items already in LOINC.

Databases, Factual↗

PubMed1994

Semantic memory and frontal executive function during transient global amnesia.

To assess semantic memory and frontal executive function, two patients underwent neuropsychological testing during transient global amnesia (TGA) and after an interval of 6-8 weeks. In spite of a profound deficit in anterograde verbal and non-verbal memory, semantic memory was normal, as judged by category fluency measures, picture naming, and picture-word and picture-picture matching, and reading ability was normal. Similarly, there were no deficits on a number of tests known to be sensitive to frontal executive dysfunction. A hexamethylpropyleneamine-oxime (HMPAO) single photon emission CT (SPECT) scan, obtained on one patient 24 hours post-TGA, showed focal left temporal lobe hypoperfusion which had resolved three months later. The observed dissociation between episodic and semantic memory is discussed in the light of contemporary cognitive theories of memory organisation.

Aged↗

PubMed2002

Functional MRI of language: new approaches to understanding the cortical organization of semantic processing.

Until recently, our understanding of how language is organized in the brain depended on analysis of behavioral deficits in patients with fortuitously placed lesions. The availability of functional magnetic resonance imaging (fMRI) for in vivo analysis of the normal brain has revolutionized the study of language. This review discusses three lines of fMRI research into how the semantic system is organized in the adult brain. These are (a) the role of the left inferior frontal lobe in semantic processing and dissociations from other frontal lobe language functions, (b) the organization of categories of objects and concepts in the temporal lobe, and (c) the role of the right hemisphere in comprehending contextual and figurative meaning. Together, these lines of research broaden our understanding of how the brain stores, retrieves, and makes sense of semantic information, and they challenge some commonly held notions of functional modularity in the language system.

Brain Mapping↗

PubMedDate not supplied

Neuronal substrates for semantic memory: a positron emission tomography study in Alzheimer's disease.

We examined 57 patients with mild Alzheimer's disease by using three kinds of verbal semantic memory tests (category fluency, confrontation naming and generation of verbal definition) and correlated each score with regional cerebral glucose metabolism determined by (18)F-fluorodeoxyglucose and positron emission tomography. The scores of all three verbal semantic memory tests correlated significantly with regional cerebral glucose metabolism in the left inferior temporal gyrus, even after controlling for the effects of age, sex and educational attainment. In contrast, the scores of the word recall test did not correlate significantly with regional cerebral glucose metaboliosm in the left inferior temporal gyrus, neither before nor after controlling for these confounders. Our results suggested that the left inferior temporal lobe contributes to verbal semantic memory.

Aged↗

PubMed1993

The effects of semantic context on voicing neutralization.

The present study examined regressive voice assimilation in Catalan in an attempt to determine a systematic explanation of complete versus incomplete voicing neutralization. Two types of contexts were constructed. In one type, semantic information was present to bias the meaning of target words. In the other type, no semantic information was present. The results showed that vowel duration distinguished underlying voicing in the neutral context only. The results suggest that neutralization occurs when semantic information is present, but that a voicing contrast is realized when it is absent.

Female↗

PubMed1980

Evaluation of psychotherapies and Osgood's Semantic Differential. A tentative approach.

Setting up a semantic differential according to Osgood for evaluating analytical psychotherapies: a selection of scales and inducive words plus a factor analysis based on answers obtained from two test groups--the one composed of ambulatory psychiatric patients, the other composed of normal individuals. Preliminary validity tests of the results for applicability in clinical situations: examples of individual semantic configurations reflecting in a plausible manner certain clinical characteristics; comparison of the configurations of a group of neurotics with those of a group of schizophrenics; example of the evolution of one configuration during the period of psychoanalytical treatment. These first tests led us to believe that the semantic differential could contribute effectively to the evaluation of psychotherapies.

Humans↗

PubMed1984

Psychoanalytic concepts of eating disorders: an empirical approach with a semantic differential (Ertel).

To study empirically some psychoanalytic assumptions concerning aspects of the oral character and manifestations of fixation and regression, 61 neurotic inpatients at a psychotherapeutic clinic were investigated using a semantic differential technique (Ertel). Each patient was judged by the differential technique on the basis of 12 object representations which, in respect to the psychoanalytic theory of development, are postulated to have connections with the oral stage. A connotative proximity in the semantic space was postulated for several 'oral connotations'. For these relevant connotations the theoretical assumptions were proved empirically. However, there were no statistical differences between several groups of patients (those with an oral fixation and those with later fixations). Furthermore single dimensions of the semantic differential technique used, in contrast to the three-dimensional analysis, allowed the differentiation of patients with oral fixations from the others simply by using object representations that ought to be relevant for the oral stage of psychosexual development.

Arousal↗

PubMed1991

Psychotherapeutic treatments evaluated with two instruments: clinical questionnaire and semantic differential.

We evaluated about 100 psychotherapeutic treatments on the Freudian model with two independent instruments: a clinical questionnaire (assessed globally and intuitively) and a semantic differential (processed through various mathematic analyses). The results obtained with the two instruments were compared, and we also compared the semantic evolution of patients with that of normal subjects. Both instruments show an undeniable average improvement among patients. The semantic differential also shows that the various 'zones' tested by the inducive words are neither equally affected by neurosis nor equally modified by treatment.

Adult↗

PubMed2000

Syntactic gender and semantic expectancy: ERPs reveal early autonomy and late interaction.

This experiment explored the effect of semantic expectancy on the processing of grammatical gender, and vice versa, in German using event-related-potentials (ERPs). Subjects were presented with correct sentences and sentences containing an article-noun gender agreement violation. The cloze probability of the nouns was either high or low. ERPs were measured on the nouns. The low-cloze nouns evoked a larger N400 than the high-cloze nouns. Gender violations elicited a left-anterior negativity (LAN, 300-600 msec) for all nouns. An additional P600 component was found only in high-cloze nouns. The N400 was independent of the gender mismatch variable; the LAN was independent of the semantic variable, whereas an interaction of the two variables was found in the P600. This finding indicates that syntactic and semantic processes are autonomous during an early processing stage, whereas these information types interact during a later processing phase.

Adult↗

PubMed2002

Object activation in semantic memory from visual multimodal feature input.

The human brain's representation of objects has been proposed to exist as a network of coactivated neural regions present in multiple cognitive systems. However, it is not known if there is a region specific to the process of activating an integrated object representation in semantic memory from multimodal feature stimuli (e.g., picture-word). A previous study using word-word feature pairs as stimulus input showed that the left thalamus is integrally involved in object activation (Kraut, Kremen, Segal, et al., this issue). In the present study, participants were presented picture-word pairs that are features of objects, with the task being to decide if together they "activated" an object not explicitly presented (e.g., picture of a candle and the word "icing" activate the internal representation of a "cake"). For picture-word pairs that combine to elicit an object, signal change was detected in the ventral temporo-occipital regions, pre-SMA, left primary somatomotor cortex, both caudate nuclei, and the dorsal thalami bilaterally. These findings suggest that the left thalamus is engaged for either picture or word stimuli, but the right thalamus appears to be involved when picture stimuli are also presented with words in semantic object activation tasks. The somatomotor signal changes are likely secondary to activation of the semantic object representations from multimodal visual stimuli.

Adult↗

PubMed2002

Semantic category interference in overt picture naming: sharpening current density localization by PCA.

The study investigated the neuronal basis of the retrieval of words from the mental lexicon. The semantic category interference effect was used to locate lexical retrieval processes in time and space. This effect reflects the finding that, for overt naming, volunteers are slower when naming pictures out of a sequence of items from the same semantic category than from different categories. Participants named pictures blockwise either in the context of same- or mixed-category items while the brain response was registered using magnetoencephalography (MEG). Fifteen out of 20 participants showed longer response latencies in the same-category compared to the mixed-category condition. Event-related MEG signals for the participants demonstrating the interference effect were submitted to a current source density (CSD) analysis. As a new approach, a principal component analysis was applied to decompose the grand average CSD distribution into spatial subcomponents (factors). The spatial factor indicating left temporal activity revealed significantly different activation for the same-category compared to the mixed-category condition in the time window between 150 and 225 msec post picture onset. These findings indicate a major involvement of the left temporal cortex in the semantic interference effect. As this effect has been shown to take place at the level of lexical selection, the data suggest that the left temporal cortex supports processes of lexical retrieval during production.

Adult↗

PubMed2002

Neural differentiation of lexico-syntactic categories or semantic features? event-related potential evidence for both.

Event-related potentials (ERPs) were used to investigate whether processing differences between nouns and verbs can be accounted for by the differential salience of visual-perceptual and motor attributes in their semantic specifications. Three subclasses of nouns and verbs were selected, which differed in their semantic attribute composition (abstract, high visual, high visual and motor). Single visual word presentation with a recognition memory task was used. While multiple robust and parallel ERP effects were observed for both grammatical class and attribute type, there were no interactions between these. This pattern of effects provides support for lexical-semantic knowledge being organized in a manner that takes account both of category-based (grammatical class) and attribute-based distinctions.

Adult↗

PubMed2004

Anticipating words and their gender: an event-related brain potential study of semantic integration, gender expectancy, and gender agreement in Spanish sentence reading.

Recent studies indicate that the human brain attends to and uses grammatical gender cues during sentence comprehension. Here, we examine the nature and time course of the effect of gender on word-by-word sentence reading. Event-related brain potentials were recorded to an article and noun, while native Spanish speakers read medium- to high-constraint Spanish sentences for comprehension. The noun either fit the sentence meaning or not, and matched the preceding article in gender or not; in addition, the preceding article was either expected or unexpected based on prior sentence context. Semantically anomalous nouns elicited an N400. Gender-disagreeing nouns elicited a posterior late positivity (P600), replicating previous findings for words. Gender agreement and semantic congruity interacted in both the N400 window--with a larger negativity frontally for double violations--and the P600 window--with a larger positivity for semantic anomalies, relative to the prestimulus baseline. Finally, unexpected articles elicited an enhanced positivity (500-700 msec post onset) relative to expected articles. Overall, our data indicate that readers anticipate and attend to the gender of both articles and nouns, and use gender in real time to maintain agreement and to build sentence meaning.

Adolescent↗

PubMed2004

Brain signatures of syntactic and semantic processes during children's language development.

Developmental aspects of language comprehension were investigated using event-related brain potentials. Children between the ages of 6 and 13 listened to passive sentences that were correct, semantically incorrect, or syntactically incorrect, and data in each condition were compared with those of adults. For semantic violations, adults demonstrated a negativity (N400), as did children, but the latency decreased with age. For syntactic violations, adults displayed an early left anterior negativity (ELAN) and a late centro-parietal positivity (P600). A syntactic negativity and a late positivity were also present for children between 7 and 13 years, again with latency decreasing with age. Six-year-olds, in contrast, did not demonstrate an ELAN effect, but a late, reduced P600 pattern for the syntactic violation condition. In the early time window, the 6-year-olds displayed a widely distributed negativity that was larger for the correct than for the syntactically incorrect condition. These data indicate that the neurophysiological basis for semantic processes during auditory sentence comprehension does not change dramatically between early childhood and adulthood. Syntactic processes for passive sentences appear to differ between early and late childhood, at least with respect to those processes reflected in the ELAN component. As there is evidence that the ELAN reflects highly automatic structure-building processes, we conclude that these processes are not yet established at age 7, but gradually develop toward adult-like processing during late childhood.

Acoustic Stimulation↗