Semantic Processing Of Words Research Articles

Neurophysiological measures of covert semantic processing in neurotypical adolescents actively ignoring spoken sentence inputs: A high-density event-related potential (ERP) study

Language comprehension requires semantic processing of individual words and their context within a sentence. Well-characterized event-related potential (ERP) components (the N400 and late positivity component (LPC/P600)) provide neuromarkers of semantic processing, and are robustly evoked when semantic errors are introduced into sentences. These measures are useful for evaluating semantic processing in clinical populations, but it is not known whether they can be evoked in more severe neurodevelopmental disorders where explicit attention to the sentence inputs cannot be objectively assessed (i.e., when sentences are passively listened to). We evaluated whether N400 and LPC/P600 could be detected in adolescents who were explicitly ignoring sentence inputs. Specifically, it was asked whether explicit attention to spoken inputs was required for semantic processing, or if a degree of automatic processing occurs when the focus of attention is directed elsewhere? High-density ERPs were acquired from twenty-two adolescents (12–17 years), under two experimental conditions: 1. individuals actively determined whether the final word in a sentence was congruent or incongruent with sentence context, or 2. passively listened to background sentences while watching a video. When sentences were ignored, N400 and LPC/P600 were robustly evoked to semantic errors, albeit with reduced amplitudes and protracted/delayed latencies. Statistically distinct topographic distributions during passive versus active paradigms pointed to distinct generator configurations for semantic processing as a function of attention. Covert semantic processing continues in neurotypical adolescents when explicit attention is withdrawn from sentence inputs. As such, this approach could be used to objectively investigate semantic processing in populations with communication deficits.

Semantic-to-autobiographical memory priming: the role of stimulus processing.

It is now well established that semantic processing can cause the activation of memories in the autobiographical memory system. Studies have shown that semantic processing of words, sounds, objects, or pictures primes autobiographical memories on voluntary and involuntary autobiographical memory tasks (the Crovitz cue-word task and the vigilance task). Known as semantic-to-autobiographical memory priming, our goal in the current study was to demonstrate that this form of priming occurs under different forms of processing (i.e., shallow versus deep), and that some forms of processing (e.g., visual mental imagery) may enhance priming in this domain. In Experiment 1, equivalent semantic-to-autobiographical priming was obtained on the vigilance task following shallow (e-counting) and deep (meaning judgements) word processing. In Experiment 2, word meaning judgements were compared to visual imagery of word meanings, and visual imagery led to more semantic-to-autobiographical priming on the vigilance task than meaning judgements. The results of these experiments support the idea that semantic-to-autobiographical priming occurs under a wide range of processing conditions, supporting a ubiquity claim, with some conditions producing more priming than others, and they further support the idea that this form of may play an important role in the production of involuntary memories in everyday life.

Effects and prediction of cognitive load on encoding model of brain response to auditory and linguistic stimuli in educational multimedia

Multimedia is extensively used for educational purposes. However, certain types of multimedia lack proper design, which could impose a cognitive load on the user. Therefore, it is essential to predict cognitive load and understand how it impairs brain functioning. Participants watched a version of educational multimedia that applied Mayer’s principles, followed by a version that did not. Meanwhile, their electroencephalography (EEG) was recorded. Subsequently, they participated in a post-test and completed a self-reported cognitive load questionnaire. The audio envelope and word frequency were extracted from the multimedia, and the temporal response functions (TRFs) were obtained using a linear encoding model. We observed that the behavioral data are different between the two groups and the TRFs of the two multimedia versions were different. We saw changes in the amplitude and latencies of both early and late components. In addition, correlations were found between behavioral data and the amplitude and latencies of TRF components. Cognitive load decreased participants’ attention to the multimedia, and semantic processing of words also occurred with a delay and smaller amplitude. Hence, encoding models provide insights into the temporal and spatial mapping of the cognitive load activity, which could help us detect and reduce cognitive load in potential environments such as educational multimedia or simulators for different purposes.

Observing gesture at learning enhances subsequent phonological and semantic processing of L2 words: An N400 study

This study employed the N400 event-related potential (ERP) to investigate how observing different types of gestures at learning affects the subsequent processing of L2 Mandarin words differing in lexical tone by L1 English speakers. The effects of pitch gestures conveying lexical tones (e.g., upwards diagonal movements for rising tone), semantic gestures conveying word meanings (e.g., waving goodbye for to wave), and no gesture were compared. In a lexical tone discrimination task, larger N400s for Mandarin target words mismatching vs. matching Mandarin prime words in lexical tone were observed for words learned with pitch gesture. In a meaning discrimination task, larger N400s for English target words mismatching vs. matching Mandarin prime words in meaning were observed for words learned with pitch and semantic gesture. These findings provide the first neural evidence that observing gestures during L2 word learning enhances subsequent phonological and semantic processing of learned L2 words.

Asymmetry in hemispheric strategies for visual recognition of homonyms

ABSTRACT The primary objective of this investigation was to explore the strategic asymmetry exhibited by the two hemispheres during semantic processing, specifically focusing on the visual recognition of homonyms. By utilizing balanced and unbalanced homonyms, we sought to ascertain whether foveal processing adheres to a specific hemisphere's strategy. In Experiment 1, we employed a visual half-field presentation paradigm to elucidate the unihemispheric strategy employed for homonym recognition. Notably, our results revealed a significant type effect, whereby responses were more accurate for unbalanced homonyms compared to balanced homonyms, particularly in the LVF/RH. This outcome suggests that the RH exhibits a stronger activation of the dominant meaning, primarily driven by frequency, while the LH concurrently activates all candidate meanings of homonyms with comparable intensity. Building upon these insights, Experiment 2 involved the presentation of both homonym types within the foveal vision, leading to the identification of a significant type effect and providing evidence for the robust utilization of the RH strategy during foveal homonym recognition. Collectively, these findings delineate an asymmetric strategy employed during semantic processing across the hemispheres, with the RH assuming a dominant role in the semantic processing of foveal words.

You are fired! Exclusion words induce cortico-spinal modulations associated with vicarious pain.

Self- and vicarious experience of physical pain induces inhibition of the motor cortex (M1). Experience of social rejections recruits the same neural network as physical pain, however, whether social pain modulates M1 corticospinal excitability remains unclear. This study examines for the first time whether social exclusion words, rather than simulated social exclusion tasks, modulate embodied sensorimotor networks during vicarious experience of other's pain. Participants observed visual sequences of painful and functional events ending with a superimposed word with either social exclusion, social inclusion, or nonsocial meaning. Motor-evoked potentials (MEPs) to single-pulse transcranial magnetic stimulation (TMS) of the left M1 were recorded at 400 or 550 ms from word onset. MEPs tended to inhibit during observation of pain, relative to functional events. Moreover, MEPs recorded at 400 ms from word onset, during pain movies, decreased following the presentation of exclusion, relative to inclusion/neutral words. The magnitude of these two modulations marginally correlated with participants' interindividual differences in personal distress and self-esteem. These findings provide evidence of vicarious responding to others' pain in the M1 corticospinal system and enhancement of such vicarious response in the earlier phases of semantic processing of exclusion words - supporting activation of social pain embodied representations.

Semantic-to-autobiographical memory priming is ubiquitous.

It is now well established that the activation of semantic memories leads to the activation of autobiographical memories. Studies have shown that semantic processing of words or pictures primes autobiographical memories on voluntary and involuntary autobiographical memory tasks (the Crovitz cue-word task and the vigilance task). Known as semantic-to-autobiographical memory priming, our goal in the current study was to demonstrate the ubiquitous nature of this form of priming by showing that a wide variety of stimuli will prime involuntary autobiographical memories on the vigilance task. In Experiment 1, semantic-to-autobiographical priming was obtained on the vigilance task following the processing of sounds (e.g., the sound of bowling) and spoken words (e.g., the word bowling). In Experiment 2, semantic-to-autobiographical priming was observed on the vigilance task following tactile processing (e.g., the objects ball, glasses) and visual word processing (e.g., the words ball, glasses). In Experiment 3, semantic-to-autobiographical priming was observed on the vigilance task following the processing of videos (e.g., videos of a marching parade) and visual word processing (e.g., the word parade). The results of these experiments support the idea that semantic-to-autobiographical activations occur across a wide variety of stimuli (e.g., linguistic, perceptual). The results also further support the idea that semantic-to-autobiographical memory priming may play an important role in the production of involuntary memories in everyday life. Additional implications (for priming theory and autobiographical memory functions) are discussed.

Looking for a word or for its meaning? The impact of induction tasks on adolescents' visual search for verbal material.

An eye-tracking experiment was conducted to examine whether the pre-activation of different word-processing pathways by means of semantic versus perceptual induction tasks could modify the way adults and 11- to 15-year-old adolescents searched for single target words within displays of nine words. The presence within the search displays of words either looking like the target word or semantically related to the target word was manipulated. The quality of participants' lexical representations was evaluated through three word-identification and vocabulary tests. Performing a semantic induction task rather than a perceptual one on the target word before searching for it increased search times by 15% in all age groups, reflecting an increase in both the number and duration of gazes directed to non-target words. Moreover, performing the semantic induction task increased the impact of distractor words that were semantically related to the target word on search efficiency. Participants' search efficiency increased with age because of a progressive increase in the quality of adolescents' lexical representations, which allowed participants to more quickly reject the distractors on which they fixated. Indeed, lexical quality scores explained 43% of the variance in search times independently of participants' age. In the simple visual search task used in this study, fostering semantic word processing through the semantic induction task slowed down visual search. However, the literature suggests that semantic induction tasks could, in contrast, help people find information more easily in more complex verbal environments where the meaning of words must be accessed to find task-relevant information.

When a Sunny Day Gives You Butterflies: An Electrophysiological Investigation of Concreteness and Context Effects in Semantic Word Processing.

Theories on controlled semantic cognition assume that word concreteness and linguistic context interact during semantic word processing. Methodological approaches and findings on how this interaction manifests at the electrophysiological and behavioral levels are heterogeneous. We measured ERPs and RTs applying a validated cueing paradigm with 19 healthy participants, who performed similarity judgments on concrete or abstract words (e.g., "butterfly" or "tolerance") after reading contextual and irrelevant sentential cues. Data-driven analyses showed that concreteness increased and context decreased negative-going deflections in broadly distributed bilateral clusters covering the N400 and N700/late positive component time range, whereas both reduced RTs. Crucially, within a frontotemporal cluster in the N400 time range, contextual (vs. irrelevant) information reduced negative-going amplitudes in response to concrete but not abstract words, whereas a contextual cue reduced RTs only in response to abstract but not concrete words. The N400 amplitudes did not explain additional variance in the RT data, which showed a stronger contextual facilitation for abstract than concrete words. Our results support separate but interacting effects of concreteness and context on automatic and controlled stages of contextual semantic processing and suggest that effects on the electrophysiological versus behavioral level obtained with this paradigm are dissociated.

Establishing a causal role for left ventrolateral prefrontal cortex in value-directed memory encoding with high-definition transcranial direct current stimulation

One critical approach for promoting the efficiency of memory is to adopt selective encoding strategies to prioritize more valuable information. Past neuroimaging studies have shown that value-directed modulation of verbal memory depends heavily on the engagement of left-lateralized semantic processing regions, particularly in the ventrolateral prefrontal cortex (VLPFC). In the present study, we used high-definition transcranial direct current stimulation (HD-tDCS) to seek evidence for a causal role of left VLPFC in supporting the memory advantage for high-value items. Three groups of healthy young adult participants were presented with lists of words to remember, with each word accompanied by an arbitrarily assigned point value. During the first session, all participants received sham stimulation as they encoded five lists of 30 words each. Two of these lists were immediately tested with free recall, with feedback given to allow participants to develop metacognitive insight and strategies to maximize their point total. The second session had the exact same structure as the first, but the groups differed in whether they received continued sham stimulation (N = 22) or anodal stimulation of the left VLPFC (N = 21) or right VLPFC (N = 20). Those lists not tested with immediate recall were tested with recognition judgments after a one-day delay. Since no brain stimulation was applied during this Day 2 test, any performance differences can be attributed to the effects of stimulation on Day 1 encoding processes. Anodal stimulation of left VLPFC significantly boosted participants’ memory encoding selectivity. In comparison, no such effect was seen in participants who received right VLPFC or sham stimulation. Estimates of recollection- and familiarity-based responding revealed that left VLPFC stimulation specifically amplified the effects of item value on recollection. These results demonstrate a causal role for left VLPFC in the implementation of selective value-directed encoding strategies, putatively by boosting deep semantic processing of high-value words. Our findings also provide further evidence on the hemispheric lateralization of value-directed verbal memory encoding.

Evidence from partially valid cueing that words are processed serially.

There has been a longstanding debate about whether lexical and semantic processing of words is serial or parallel. We addressed this debate using partially valid cueing, where one of two words is cued. The cue was valid on 80% and invalid on the other 20% of the trials. The task was semantic categorization, and performance was measured by accuracy. The new feature was to limit attentional switching using a postmask of consonants that closely followed the presentation of words. We found a large effect of cueing and, most importantly, performance for the uncued word was at chance. This chance performance was consistent with serial processing, but not with typical parallel processing. This result adds to the evidence from other recent studies that the lexical and semantic processing of words is serial.

Parafoveal preview benefit in a conflicting sentential context: Evidence from ERPs.

In natural reading, the reader's processing of a word starts when the word is located in parafoveal vision. Relative to a situation with an invalid preview, fixations are significantly shorter after a fully valid, identical preview. Although research on the identity preview benefit has been ongoing for more than 40 years, the mechanism of this preview benefit, the level of lexical processing it occurs, and its relationship to the sentential context remain unclear. This study employed EEG brain component analysis technology to address these questions in Chinese sentence reading. We manipulated the sentential context to make the target word plausible or not plausible with the sentence and manipulated the target word present or not present in preview. EEG results showed that the identity preview benefit can affect not only the early preview positivity, reflecting the early orthographic processing of words, but also the N400 and LPC components, reflecting the late and in-depth semantic processing of words. Conflicting sentential context, in which the target word is implausible and cannot be integrated into the sentence, can interfere temporarily with these processes. These findings suggest that in the process of sentence reading, an identical preview word can promote the subsequent reading process at multiple levels, and its role is modulated by contextual information.

The effect of letter-case type on the semantic processing of words and sentences during attentive and mind-wandering states

AbstractThe task of finding a case type that, on average, enhances the processing of verbal material has yielded mixed results in the literature. This study tackled this issue with an eye to the issue of processing textual information on road signs and the additional consideration of readers’ attentive states. Participants (n = 104) completed three experiments, the first two of which made use of both short (i.e., attentive state) and long (i.e., nonattentive or mind-wandering state) inter-trial intervals (ITIs). Experiment I consisted of a living versus non-living category-decision task involving the presentation of single words. Experiment II consisted of a sensical versus nonsensical sentence-judgment task. Experiment III consisted of a recognition memory task for words presented during the category-decision task. No significant difference in letter-case-type effectiveness was found for either the semantic categorization of or memory for single words. On the other hand, sensical sentences were correctly judged more quickly in lower case (or, more precisely, sentence case with the first letter of the first word capitalized). Such results point to either a more fluent processing of or enhanced conceptual resonance for sentences presented in lower case.

Frequency-based foveal load modulates semantic parafoveal-on-foveal effects

During reading, we can process words allocated to the parafoveal visual region. Our ability to extract parafoveal information is determined by the availability of attentional resources, and by how these are distributed among words in the visual field. According to the foveal load hypothesis, a greater difficulty in processing the foveal word would result in less attentional resources being allocated to the parafoveal word, thereby hindering its processing. However, contradictory results have raised questions about which foveal load manipulations may affect the processing of parafoveal words at different levels. We explored whether the semantic processing of parafoveal words can be modulated by variations in a frequency-based foveal load. When participants read word triads, modulations in the N400 component indicated that, while parafoveal words were semantically processed when foveal load was low, their meaning could not be accessed if the foveal word was more difficult to process. Therefore, a frequency-based foveal load modulates semantic parafoveal processing and a semantic preview manipulation may be a suitable baseline to test the foveal load hypothesis. • The meaning of words allocated in the parafoveal region is processed and integrated. • Frequency-based foveal load modulates semantic processing of parafoveal words. • Electrophysiological measures are more sensible to detect subtle parafoveal effects. • Attentional resources must be available for semantic parafoveal-on-foveal effects to occur.

Language and nonverbal auditory processing in the occipital cortex of individuals who are congenitally blind due to anophthalmia

Individuals with congenital blindness due to bilateral anophthalmia offer a unique opportunity to examine cross-modal plasticity in the complete absence of any stimulation of the ‘visual’ pathway even during development in utero. Our previous work has suggested that this complete sensory deafferentation results in different patterns of reorganisation compared with those seen in other early blind populations. Here, we further test the functional specialisation of occipital cortex in six well-studied cases with anophthalmia. Whole brain functional MRI was obtained while these human participants and a group of sighted controls performed two experiments involving phonological and semantic processing of words (verbal experiment) and spatial and identity processing of piano chords (nonverbal experiment). Both experiments were predicted to show a dorsal-ventral difference in activity based on the specific task performed. All tasks evoked activation in occipital cortex in the individuals with anophthalmia but not in the sighted controls. For the verbal experiment, both dorsal and ventral occipital areas were strongly activated by the phonological and semantic tasks in anophthalmia. For the nonverbal experiment, both the spatial and the identity task robustly activated the dorsal occipital area V3a but showed inconsistent activity elsewhere in the occipital lobe. V1 was most strongly activated by the verbal tasks, showing greater activity on the left for the verbal task relative to the nonverbal one. For individual anophthalmic participants, however, activity in V1 was inconsistent across tasks and hemispheres with many participants showing activity levels in the control range, which was not significantly above baseline. Despite the homogeneous nature of the cause of blindness in the anophthalmic group, there remain differences in patterns of activation among the individuals with this condition. Investigation at the case level might further our understanding of how post-natal experiences shape functional reorganisation in deafferented cortex.

Multiple functions of the angular gyrus at high temporal resolution.

Here, the functions of the angular gyrus (AG) are evaluated in the light of current evidence from transcranial magnetic/electric stimulation (TMS/TES) and EEG/MEG studies. 65 TMS/TES and 52 EEG/MEG studies were examined in this review. TMS/TES literature points to a causal role in semantic processing, word and number processing, attention and visual search, self-guided movement, memory, and self-processing. EEG/MEG studies reported AG effects at latencies varying between 32 and 800ms in a wide range of domains, with a high probability to detect an effect at 300-350ms post-stimulus onset. A three-phase unifying model revolving around the process of sensemaking is then suggested: (1) early AG involvement in defining the current context, within the first 200ms, with a bias toward the right hemisphere; (2) attention re-orientation and retrieval of relevant information within 200-500ms; and (3) cross-modal integration at late latencies with a bias toward the left hemisphere. This sensemaking process can favour accuracy (e.g. for word and number processing) or plausibility (e.g. for comprehension and social cognition). Such functions of the AG depend on the status of other connected regions. The much-debated semantic role is also discussed as follows: (1) there is a strong TMS/TES evidence for a causal semantic role, (2) current EEG/MEG evidence is however weak, but (3) the existing arguments against a semantic role for the AG are not strong. Some outstanding questions for future research are proposed. This review recognizes that cracking the role(s) of the AG in cognition is possible only when its exact contributions within the default mode network are teased apart.

Cognitive-Motor Dissociation Following Pediatric Brain Injury: What About the Children?

Background and ObjectivesFollowing severe brain injury, up to 16% of adults showing no clinical signs of cognitive function nonetheless have preserved cognitive capacities detectable via neuroimaging and neurophysiology; this has been designated cognitive-motor dissociation (CMD). Pediatric medicine lacks both practice guidelines for identifying covert cognition and epidemiologic data regarding CMD prevalence.MethodsWe applied a diverse battery of neuroimaging and neurophysiologic tests to evaluate 2 adolescents (aged 15 and 18 years) who had shown no clinical evidence of preserved cognitive function following brain injury at age 9 and 13 years, respectively. Clinical evaluations were consistent with minimally conscious state (minus) and vegetative state, respectively.ResultsBoth participants' EEG, and 1 participant's fMRI, provided evidence that they could understand commands and make consistent voluntary decisions to follow them. Both participants' EEG demonstrated larger-than-expected responses to auditory stimuli and intact semantic processing of words in context.DiscussionThese converging lines of evidence lead us to conclude that both participants had preserved cognitive function dissociated from their motor output. Throughout the 5+ years since injury, communication attempts and therapy had remained uninformed by such objective evidence of their cognitive abilities. Proper diagnosis of CMD is an ethical imperative. Children with covert cognition reflect a vulnerable and isolated population; the methods outlined here provide a first step in identifying such persons to advance efforts to alleviate their condition.

Temporal and topographical changes in theta power between middle childhood and adolescence during sentence comprehension

Time frequency analysis of the EEG is increasingly used to study the neural oscillations supporting language comprehension. Although this method holds promise for developmental research, most existing work focuses on adults. Theta power (4–8 Hz) in particular often corresponds to semantic processing of words in isolation and in ongoing text. Here we investigated how the timing and topography of theta engagement to individual words during written sentence processing changes between childhood and adolescence (8–15 years). Results show that topographically, the theta response is broadly distributed in children, occurring over left and right central-posterior and midline frontal areas, and localizes to left central-posterior areas by adolescence. There were two notable developmental shifts. First, in response to each word, early (150–300 msec) theta engagement over frontal areas significantly decreases between 8 and 9 years and 10–11 years. Second, throughout the sentence, theta engagement over the right parietal areas significantly decreases between 10 and 11 years and 12–13 years with younger children’s theta response remaining significantly elevated between words compared to adolescents’. We found no significant differences between 12 and 13 years and 14–15 years. These findings indicate that children’s engagement of the language network during sentence processing continues to change through middle childhood but stabilizes into adolescence.

What's "up"? Impaired Spatial Preposition Processing in Posterior Cortical Atrophy.

This study seeks to confirm whether lesions in posterior regions of the brain involved in visuo-spatial processing are of functional relevance to the processing of words with spatial meaning. We investigated whether patients with Posterior Cortical Atrophy (PCA), an atypical form of Alzheimer’s Disease which predominantly affects parieto-occipital brain regions, is associated with deficits in working memory for spatial prepositions. Case series of patients with PCA and matched healthy controls performed tests of immediate and delayed serial recall on words from three lexico-semantic word categories: number words (twelve), spatial prepositions (behind) and function words (e.g., shall). The three word categories were closely matched for a number of psycholinguistic and semantic variables including length, bi-/tri-gram frequency, word frequency, valence and arousal. Relative to controls, memory performance of PCA patients on short word lists was significantly impaired on spatial prepositions in the delayed serial recall task. These results suggest that lesions in posterior parieto-occipital regions specifically impair the processing of spatial prepositions. Our findings point to a pertinent role of posterior cortical regions in the semantic processing of words with spatial meaning and provide strong support for modality-specific semantic theories that recognize the necessary contributions of sensorimotor regions to conceptual semantic processing.

Electrophysiological correlates of character transposition in two-character Chinese word identification

The present study investigated brain activity elicited by character transposition processing of two-character Chinese words using event-related potentials (ERPs) with a two-target rapid serial visual presentation (RSVP) task. The behavioral results showed higher accuracy with canonical and transposed words than pseudowords in the short stimulus onset asynchrony (SOA, 249 ms) condition, but not in the long SOA (581 ms) condition. Additionally, relative to the pseudoword condition, the ERP results indicated that the canonical and transposed words elicited statistically less negative N250 and N400 amplitudes. Furthermore, both the canonical and transposed words revealed no significant differences in the early N100, P200, and N250 components, whereas a significant difference was observed in the N400 amplitude regardless of the SOAs between the two constituent characters, indicating less semantic activation. Taken together, our electrophysiological data indicate that early ERP components are not sensitive to Chinese character transposition. In contrast, such morpheme transposition affects the semantic processing of Chinese compound words.