Levels Of Semantic Processing Research Articles

HD-tDCS of primary and higher-order motor cortex affects action word processing.

The contribution of action-perception systems of the brain to lexical semantics remains controversial. Here, we used high-definition transcranial direct current stimulation (HD-tDCS) in healthy adults to examine the role of primary (left hand motor area; HMA) and higher-order (left anterior inferior parietal lobe; aIPL) action areas in action-related word processing (action verbs and manipulable nouns) compared to non-action-related control words (non-action verbs and non-manipulable nouns). We investigated stimulation-related effects at three levels of semantic processing: subliminal, implicit, and explicit. Broadly, we found that stimulation of HMA and aIPL resulted in relative facilitation of action-related language processing compared to non-action. HMA stimulation facilitated action verb processing in subliminal and implicit task contexts, suggesting that HMA helps represent action verbs even in semantically shallow tasks. HMA stimulation also facilitated manipulable noun comprehension in an explicit semantic task, suggesting that HMA contributes to manipulable noun comprehension when semantic demands are high. aIPL stimulation facilitated both manipulable noun and action verb processing during an implicit task. We suggest that both HMA and aIPL play a functional role in action semantics. HMA plays a general role in the semantics of actions and manipulable objects, while aIPL is important only when visuo-motor coordination is required for the action.

Semantic priming effects can be modulated by crosslinguistic interactions during second-language auditory word recognition

AbstractThe current study investigates how second languageauditoryword recognition, in early and highly proficient Spanish–Basque (L1-L2) bilinguals, is influenced by crosslinguistic phonological-lexical interactions and semantic priming. Phonological overlap between a word and its translation equivalent (phonological cognate status), and semantic relatedness of a preceding prime were manipulated. Experiment 1 examined word recognition performance in noisy listening conditions that introduce a high degree of uncertainty, whereas Experiment 2 employed clear listening conditions, with low uncertainty. Under noisy listening conditions, semantic priming effects interacted with phonological cognate status: for word recognition accuracy, a related prime overcame inhibitory effects of phonological overlap between target words and their translations. These findings are consistent with models of bilingual word recognition that incorporate crosslinguistic phonological-lexical-semantic interactions. Moreover, they suggest an interplay between L2-L1 interactions and the integration of information across acoustic and semantic levels of processing in flexibly mapping the speech signal onto the spoken words, under adverse listening conditions.

Development of bidirectional phono-semantic activation in toddlers.

A mediated priming effect refers to the activation of a target via a mediator previously activated by a prime. This effect has been found at 24 months of age for phono-semantic links: a prime ( cup) activates a target ( dog) via a mediator ( cat), providing evidence of activation in a forward direction (phonological to semantic). Interactive models, however, propose that activation propagates in both forward and backward directions between processing levels. This study investigated the development of bidirectional co-activation of phonological and semantic levels of processing in Spanish-speaking toddlers. In a primed preferential looking task, participants were exposed to an unlabelled prime image, followed by the presentation of two images, a target and a distractor. In Experiment 1, when images with a semantic-phonological relationship were presented, both 24- and 30-month-olds preferred to look at the named target with a relationship to the prime image ( dog- cat- cup). However, when an unrelated target image was named, 24-month-olds preferred to look at the target, but 30-month-olds did not. In Experiment 2, both 24- and 30-month-olds preferred to look at a target with a phono-semantic relationship to the prime ( cup- cat- dog) over an unrelated target. These results provide strong evidence of differences in the development of forward and backward interactions between semantic and phonological processing levels.

Enhanced semantic priming in synesthetes independent of sensory binding.

Synesthesia is the phenomenon in which individuals experience unusual involuntary cross-modal pairings. The evidence to date suggests that synesthetes have access to advantageous item-specific memory cues linked to their synesthetic experience, but whether this emphasis on item-specific memory cues comes at the expense of semantic-level processing has not been unambiguously demonstrated. Here we found that synesthetes produce substantially greater semantic priming magnitudes, unrelated to their specific synesthetic experience. This effect, however, was moderated by whether the synesthetes were projectors (their synesthetic experience occurs in their representation of external space), or associators (their synesthetic experience occurs in their 'mind's eye'). That is, the greater a synesthetes's tendency to project their experience, the weaker their semantic priming when the task did not require them to semantically categorize the stimuli, whereas this trade-off was absent when the task did have that requirement.

Priming effects under continuous flash suppression: An examination on subliminal bottom‐up processing

AbstractBinocular rivalry is a bistable perception that occurs when two dissimilar stimuli are presented to each eye. Recent studies have demonstrated that the reaction time to target words under binocular rivalry was shortened when semantically related prime words were presented supraliminally (Costello, Jiang, Baartman, McGlennen, & He, 2009). We investigated whether three types of priming (repetition, semantic, and cross‐script) occurred from the prime words presented under binocular rivalry, by using continuous flash suppression paradigm (Tsuchiya, Koch, Gilroy, & Blake, 2006). The prime words presented to the suppressed eye invoked repetition and cross‐script priming, but not semantic priming. The results suggested that the stimuli presented to the suppressed eye underwent shape and phonological level processing, but not semantic level processing.

Électrophysiologie et vulnérabilité schizophrénique : la composante N400 comme endophénotype candidat ?

Research on early stages of schizophrenia aims to provide early, objective, and stable markers of vulnerability. In this review, we first briefly describe the notion of such markers, or endophenotypes, notably in terms of stability, specificity and heritability. Among other empirical approaches, event-related potentials (ERPs) have been recently considered as putative endophenotypes. The N400 component is an event-related brain potential classically elicited during semantic processing, as suggested by a growing body of empirical studies with a large variety of paradigms. We provide here a short account of its typical descriptions and the interpretations of its functional significance. Then we describe the main current results about schizophrenic alterations of the N400 component. Two levels of semantic processing (automatic spreading and controlled mechanisms) are disturbed in schizophrenia, even if the underlying mechanisms remain unclear or discussed. Several controversial issues may also need further research, such as the influence of symptomatology and evolution of schizophrenia. Another crucial topic concerns the putative schizophrenic specificity, and only little is known about possible alterations of N400 in affective disorders. We discuss the notion of heritability, mainly explored in current literature among people with schizotypal personality. Finally, even if N400 studies contribute to a better understanding of linguistic disturbances in schizophrenia, it appears difficult to consider the N400 component as a relevant schizophrenic endophenotype, given the current paucity of results on its stability, its heritability (clinical and genetic vulnerability) and its schizophrenic specificity.

Evidence for a limited-cascading account of written word naming.

We address the issue of how information flows within the written word production system by examining written object-naming latencies. We report 4 experiments in which we manipulate variables assumed to have their primary impact at the level of object recognition (e.g., quality of visual presentation of pictured objects), at the level of semantic processing (contextual constraint), and at the level of the lexical retrieval of orthographic word forms (e.g., word frequency). In Experiment 1, pictures were presented either in color or in black and white and had names with either high-to-low or low-to-high frequency trajectories. Both factors had reliable but entirely additive effects on written naming times. In Experiment 2, pictures were presented clearly, in visual noise or blurred, and had names of either high or low word frequency. Again, both factors had reliable but additive effects on written naming latencies. In Experiments 3 and 4, pictures were preceded by a sentence that provided either strong or weak contextual constraint and had names of either high or low word frequency. These 2 variables interacted: The advantage for high-frequency words was observed only with low contextual constraint. We argue that, in combination, these findings support a limited-cascading account of written word production.

Frontal theta and alpha power and coherence changes are modulated by semantic complexity in Go/NoGo tasks

To study the interactions between semantic processing and motor response inhibition, we recorded scalp EEG as subjects performed a series of Go/NoGo response inhibition tasks whose response criteria depended on different levels of semantic processing. Three different tasks were used. The first required the subject to make a Go/NoGo decision based on pictures of one particular car or one particular dog. The second used pictures of different types of cars and of dogs, and the final task used stimuli that ranged across multiple types of objects and animals. We found that the theta-band EEG power recorded during the NoGo response was attenuated as a function of semantic complexity while the peak latency was delayed in only the most complex category task. Further, frontal alpha-band desynchronization was strongest for the simplest task and remained close to baseline for the other tasks. Finally, there was significant theta-band coherence between the frontal pole and pre-SMA for the NoGo conditions across tasks, which was not found in the Go trials. These findings provide information about how more rostral frontal regions interact with the pre-SMA during response inhibition across different stimuli and task demands: specifically, level of processing affects latency, difficulty affects amplitude, and coherence is affected by whether the decision is Go or NoGo.

Using prosody to improve automatic speech recognition

In this paper acoustic processing and modelling of the supra-segmental characteristics of speech is addressed, with the aim of incorporating advanced syntactic and semantic level processing of spoken language for speech recognition/understanding tasks. The proposed modelling approach is very similar to the one used in standard speech recognition, where basic HMM units (the most often acoustic phoneme models) are trained and are then connected according to the dictionary and some grammar (language model) to obtain a recognition network, along which recognition can be interpreted also as an alignment process. In this paper the HMM framework is used to model speech prosody, and to perform initial syntactic and/or semantic level processing of the input speech in parallel to standard speech recognition. As acoustic–prosodic features, fundamental frequency and energy are used. A method was implemented for syntactic level information extraction from the speech. The method was designed to work for fixed-stress languages, and it yields a segmentation of the input speech for syntactically linked word groups, or even single words corresponding to a syntactic unit (these word groups are sometimes referred to as phonological phrases in psycholinguistics, which can consist of one or more words). These so-called word-stress units are marked by prosody, and have an associated fundamental frequency and/or energy contour which allows their discovery. For this, HMMs for the different types of word-stress unit contours were trained and then used for recognition and alignment of such units from the input speech. This prosodic segmentation of the input speech also allows word-boundary recovery and can be used for N-best lattice rescoring based on prosodic information. The syntactic level input speech segmentation algorithm was evaluated for the Hungarian and for the Finnish languages that have fixed stress on the first syllable. (This means if a word is stressed, stress is realized on the first syllable of the word.) The N-best rescoring based on syntactic level word-stress unit alignment was shown to augment the number of correctly recognized words. For further syntactic and semantic level processing of the input speech in ASR, clause and sentence boundary detection and modality (sentence type) recognition was implemented. Again, the classification was carried out by HMMs, which model the prosodic contour for each clause and/or sentence modality type. Clause (and hence also sentence) boundary detection was based on HMM’s excellent capacity in aligning dynamically the reference prosodic structure to the utterance coming from the ASR input. This method also allows punctuation to be automatically marked. This semantic level processing of speech was investigated for the Hungarian and for the German languages. The correctness of recognized types of modalities was 69% for Hungarian, and 78% for German.

The role of personal experience in the neural processing of action-related language

We investigated how auditory language processing is modified by a listener’s previous experience with the specific activities mentioned in the speech. In particular, we asked whether neural responses related to language processing depend on one’s experience with the action-based content of this language. Ice-hockey players and novices passively listened to sentences about ice-hockey and everyday situations during functional magnetic resonance imaging (fMRI). When listening to action-related sentences, neural activation in left inferior frontal gyrus (IFG) and left dorsal premotor cortex (PMd) depended on one’s actual (physical) experience with the action described in the sentence: hockey experts showed greater activity in these regions than novices for hockey sentences, but not for everyday-action sentences. Thus, personal experience with linguistic content modulated activity both in regions associated with language comprehension (IFG) and in those related to complex action planning (PMd). Moreover, hockey experts (who have extensive experience with both hockey and everyday situations) showed greater activity in left IFG regions for hockey relative to everyday sentences. This suggests that the degree to which one finds information personally relevant (i.e., over and above one’s direct experience with it) also modulates processing in brain regions related to semantic-level processing.

Distinguishing the processing of gestures from signs in deaf individuals: An fMRI study

Manual gestures occur on a continuum from co-speech gesticulations to conventionalized emblems to language signs. Our goal in the present study was to understand the neural bases of the processing of gestures along such a continuum. We studied four types of gestures, varying along linguistic and semantic dimensions: linguistic and meaningful American Sign Language (ASL), non-meaningful pseudo-ASL, meaningful emblematic, and nonlinguistic, non-meaningful made-up gestures. Pre-lingually deaf, native signers of ASL participated in the fMRI study and performed two tasks while viewing videos of the gestures: a visuo-spatial (identity) discrimination task and a category discrimination task. We found that the categorization task activated left ventral middle and inferior frontal gyrus, among other regions, to a greater extent compared to the visual discrimination task, supporting the idea of semantic-level processing of the gestures. The reverse contrast resulted in enhanced activity of bilateral intraparietal sulcus, supporting the idea of featural-level processing (analogous to phonological-level processing of speech sounds) of the gestures. Regardless of the task, we found that brain activation patterns for the nonlinguistic, non-meaningful gestures were the most different compared to the ASL gestures. The activation patterns for the emblems were most similar to those of the ASL gestures and those of the pseudo-ASL were most similar to the nonlinguistic, non-meaningful gestures. The fMRI results provide partial support for the conceptualization of different gestures as belonging to a continuum and the variance in the fMRI results was best explained by differences in the processing of gestures along the semantic dimension.

An examination of semantic radical combinability effects with lateralized cues in Chinese character recognition

Auclair and Siéroff examined lateralized cuing effects in the identification of centrally presented letter strings and reported no cuing effects for short word stimuli. They argued for a redistribution of attention over the entire word for short familiar words. We explored cuing effects with Chinese phonetic compounds, which can be considered extreme examples of short words, in a character-level semantic judgment task. When the semantic radical position was placed on the left of the characters, strong radical combinability and semantic transparency effects were observed. There was also a significant interaction between cue position (left vs. right) and radical combinability: A left cue facilitated semantic judgment of characters with small radical combinability more than did a right cue. This behavior reflects the information profile of Chinese phonetic compounds. Semantic radicals with small combinability are more informative than those with large combinability in determining the meaning of the whole character; they therefore benefit more from a left than a right cue. A mechanism redistributing attention over the whole of the character was not in evidence at the level of semantic processing.

The role of lexical competition and acoustic–phonetic structure in lexical processing: Evidence from normal subjects and aphasic patients

This study examined the effects that the acoustic–phonetic structure of a stimulus exerts on the processes by which lexical candidates compete for activation. An auditory lexical decision paradigm was used to investigate whether shortening the VOT of an initial voiceless stop consonant in a real word results in the activation of the lexical–semantic network of its voiced competitor, i.e., does acoustically modified time prime penny via dime. Results for normal subjects showed semantic priming for related pairs and mediated priming for voiced competitors, consistent with cascade models of language processing allowing for interaction between phonological and semantic levels of processing. Although Broca’s aphasics showed semantic priming ( dime primed penny), they failed to show priming in the context of a lexical competitor. These results are consistent with the hypothesis that these patients have a lexical processing deficit characterized by an overall reduction in lexical activation.

N200, N250r, and N400 event-related brain potentials reveal three loci of repetition priming for familiar names.

The authors assessed immediate repetition effects on event-related potentials (ERPs) while participants performed familiarity decisions for written personal names. For immediately repeated familiar names, the authors observed 3 distinct ERP modulations. At 180-220 ms, a posterior N200 effect occurred for names preceded by same-font primes only. In addition, an increased left temporal negativity (N250r, 220-300 ms) and a reduced central-parietal negativity (N400, 300-400 ms) were seen both for same-font and different-font repetitions. In a 2nd experiment, when names were preceded by either their corresponding face or the face of a different celebrity, only the N400 effect was preserved. These findings suggest that the N200, N250r, and N400 effects reflect facilitated processing at font-specific featural, lexical, and semantic levels of processing, respectively.

Distinct Cortical Areas for Names of Numbers and Body Parts Independent of Language and Input Modality

Some models of word comprehension postulate that the processing of words presented in different modalities and languages ultimately converges toward common cerebral systems associated with semantic-level processing and that the localization of these systems may vary with the category of semantic knowledge being accessed. We used functional magnetic resonance imaging to investigate this hypothesis with two categories of words, numerals, and body parts, for which the existence of distinct category-specific areas is debated in neuropsychology. Across two experiments, one with a blocked design and the other with an event-related design, a reproducible set of left-hemispheric parietal and prefrontal areas showed greater activation during the manipulation of topographical knowledge about body parts and a right-hemispheric parietal network during the manipulation of numerical quantities. These results complement the existing neuropsychological and brain-imaging literature by suggesting that within the extensive network of bilateral parietal regions active during both number and body-part processing, a subset shows category-specific responses independent of the language and modality of presentation.

Hemispheric lateralization at different levels of human auditory word processing: a functional magnetic resonance imaging study

We used functional magnetic resonance imaging to disentangle the functional anatomy of brain systems involved in the processing of auditory word form and meaning. Three monitoring tasks on auditory stimuli, aimed at phonetic, lexical and semantic processing, were used. We found no lateralization of temporal lobe activations, when word processing was contrasted versus the complex phonetic task. Bilateral middle temporal activations (Brodmann Area [BA] 21) were attributed to processing of word-form. Areas specific to semantic processing were restricted to the left hemisphere: the posterior middle frontal (BA 9) and posterior parietal (BA 7/40) cortex, as well as an inferior temporal area (BA 20/21). Our data suggest, that left hemispheric dominance for auditory word comprehension occurred at the level of semantic processing.

Semantic processing of words in selective listening: an examination using recognition tests and event-related brain potentials

Two experiments were conducted to investigate the degree of semantic processing for unattended words. In a dichotic listening task, each participant was required to attend selectively to either a word sequence in one ear or a speech passage in the opposite ear. The selective listening was confirmed by attenuated P1-N1 and N400 waves of the event-related brain potential to unattended words. The N400 attenuation with semantic priming was observed only for attended words. In a following recognition test with a booklet and auditory presentation, the percentage of false alarms for "new" words (or lures) semantically related to "old" words was higher when the "old" words were attended in selective listening than when unattended. These findings suggest that selective attention can act before and/or at a level of semantic processing.

A TWO-LEVELED CLASSIFICATION AND RETRIEVAL TECHNIQUE FOR PROCESS PROGRAM REUSE

This paper proposes a classification and retrieval technique for process program reuse, which is composed of a syntax and a semantic level processing. The syntax level uses the process features of: phase, paradigm, technique, standard, and application domain. The facet approach is applied here, in which each feature corresponds to a facet. Since no complicated computations are involved, this level is expected to be efficient. Regarding the semantic level, it uses the process program contents of: product, product component, exception, work assignment, tool, and role. They are organized into a semantic network for classification and retrieval. Since process program contents are used, this level is expected to be precise. It, however, may be inefficient, because complicated computations are involved. The proposed classification and retrieval technique uses the syntax level processing before the semantic level. Since most unreusable process programs are filtered out in the syntax level, the semantic level operates on relatively few process programs. Therefore, this technique is expected to be both efficient and precise.

Long-term semantic priming: A computational account and empirical evidence.

Semantic priming is traditionally viewed as an effect that rapidly decays. A new view of long-term word priming in attractor neural networks is proposed. The model predicts long-term semantic priming under certain conditions. That is, the task must engage semantic-level processing to a sufficient degree. The predictions were confirmed in computer simulations and in 3 experiments. Experiment 1 showed that when target words are each preceded by multiple semantically related primes, there is long-lag priming on a semantic-decision task but not on a lexical-decision task. Experiment 2 replicated the long-term semantic priming effect for semantic decisions with only one prime per target. Experiment 3 demonstrated semantic priming with much longer word lists at lags of 0, 4, and 8 items. These are the first experiments to demonstrate a semantic priming effect spanning many intervening items and lasting much longer than a few seconds.

The application of morpho-syntactic language processing to effective phrase matching

The application of automatic natural language processing techniques to the indexing and the retrieval of text information has been a target of information retrieval researchers for some time. Incorporating semantic-level processing of language into retrieval has led to conceptual information retrieval, which is effective but usually restricted in its domain. Using syntactic-level analysis is domain-independent, but has not yet yielded significant improvements in retrieval quality. This paper describes a process whereby a morpho-syntactic analysis of phrases or user queries is used to generate a structured representation of text. A process of matching these structured representations is then described that generates a metric value or score indicating the degree of match between phrases. This scoring can then be used for ranking the phrases. In order to evaluate the effectiveness or quality of the matching and scoring of phrases, some experiments are described that indicate the method to be quite useful. Ultimately the phrasematching technique described here would be used as part of an overall document retrieval strategy, and some future work towards this direction is outlined.