Processing Of Word Meaning Research Articles

Brain activation patterns of English language semantic processing in autistic groups

BackgroundAutism is a neurodevelopmental disorder, and there are certain differences in the brain activation patterns of English language semantic processing among autistic individuals. The research aims to explore the brain activation patterns of autistic groups during English semantic processing thus to enhance their understanding of language development.Subjects and MethodsThe study used functional Magnetic Resonance Imaging (fMRI) technology, combined with the task paradigm of English word meaning processing, to study the brain activation patterns of individuals with autism. By comparing the differences in brain activation patterns between two groups in word meaning processing tasks, researchers attempted to reveal the specific neural mechanisms involved in language processing in autistic groups. At the same time, SPSS23.0 statistical software was used to process the data.ResultsThrough comparative experiments, the Hamilton Anxiety Rating Scale (HAMA) score and Generalized Self-Efficacy Scale (GSES) score of the experimental group were 7.53 and 31.24 respectively; The HAMA and GSES scores of the control group were 10.84 and 25.81, respectively. The results indicate that the processing of English language word meanings has a brain activation effect on people with autism.Conclusions Research can promote the understanding of the cognitive and neural mechanisms of autism, and contribute to improving daily communication and life quality for autistic groups.AcknowledgementThe Education Department of Hainan Province (No. Hnjgzc2022-121); The Education Department of Hainan Province (No. Hnjgw2022-13).

Context effects in language comprehension: The role of emotional state and attention on semantic and syntactic processing.

Semantics and syntax are core components of language. The prevailing view was that processing of word meaning and syntactic processing happens in isolation from other systems. In light of proofed interactions between language and other systems, especially with perception, action and emotion, this view became untenable. This article reviews Event-related potential studies conducted at the Donders Centre for Cognition exploring the interplay between language comprehension and a person's emotional state. The research program was aimed at an investigation of the online effects of emotional state on semantic processing and syntactic processing. To this aim we manipulated mood via film fragments (happy vs. sad) before participants read neutral sentences while their EEG was recorded. In Part 1, it is shown that mood impacts online semantic processing (as indicated by N400) and the processing of syntactic violations (as indicated by P600). Part 2 was directed at a further determination of the mechanisms underlying these interactions. The role of heuristics was examined by investigating the effects of mood on the P600 to semantic reversals. The results revealed that mood affects heuristic processing. The next step consisted of an assessment of the role of attention, in the mood-by-semantics and mood-by-syntax interaction. This was accomplished by recording EEG while manipulating attention via task next to emotional state. Participants performed a semantic or syntactic judgment task vs. a letter-size judgment task. The main ERP results were as follows: (i) attention interacts with the mood effect on semantic processing and syntactic processing, respectively, (ii) the effects of mood on semantic processing and syntactic processing are reliable, and (iii) the mood effects on semantic processing are not fixed but context-dependent. In Part 3 the effects of mood on the processing of script knowledge and general world knowledge are presented. Part 4 closes with a discussion of the mechanisms involved in the mood-by-language interactions and recommendations for future research. Regarding the underlying mechanism we propose that heuristics based on semantic expectancies or syntactic expectancies play a key role in the mood-by-language interactions. The results support the view that language takes place in continuous interaction with other (non-language) systems.

A pilot study exploring the effectiveness of a whole-school intervention targeting receptive vocabulary in the early years: Findings from a mixed method study involving students as part of a practice-based research placement

Studies that have examined whole-school interventions that target conceptual knowledge reveal characteristics that are important in the delivery of a deep processing approach to word learning. These consist of explicit instruction, play, and multi-sensory experiences that are situated within and repeated across varied contexts. Word Aware (WA) is an example of a vocabulary intervention that incorporates such features. This study examined the effectiveness of the Early Years version of the WA programme in supporting the development of vocabulary knowledge in a sample of 92 children comparing them to a control group of 31 children who received usual teaching. Student speech and language therapists supported the testing and delivery of a 10-week intervention as part of their clinical placement and were interviewed along with the teachers on their perceptions of the intervention and their experiences collaborating with staff to support the whole school delivery of the programme. Informal and standardised assessment scores of receptive vocabulary showed no significant difference in the overall improvement between both groups despite finding significant improvement within each group on words targeted for intervention. Qualitative thematic analysis revealed positive observations of child engagement with aspects of the programme that aimed to promote a deep processing of word meaning. Students reported an increased sense of confidence in their ability to collaborate with teaching staff and in their willingness to engage in research as part of their clinical practice. The ceiling effects reported in the outcome measures of both the intervention and control group suggest that the WA programme may be better suited to a sample of younger-aged children. The study provides original insight into the student experience of working in a whole-class environment whilst conducting practice-based research as part of clinical placement. The methodological limitations of this study are discussed along with suggestions for future research.

Orienting to different dimensions of word meaning alters the representation of word meaning in early processing regions.

Conscious processing of word meaning can be guided by attention. In this event-related functional magnetic resonance imaging study in 22 healthy young volunteers, we examined in which regions orienting attention to two fundamental and generic dimensions of word meaning, concreteness versus valence, alters the semantic representations coded in activity patterns. The stimuli consisted of 120 nouns in written or spoken modality which varied factorially along the concreteness and valence axis. Participants performed a forced-choice judgement of either concreteness or valence. Rostral and subgenual anterior cingulate were strongly activated during valence judgement, and precuneus and the dorsal attention network during concreteness judgement. Task and stimulus type interacted in right posterior fusiform gyrus, left lingual gyrus, precuneus, and insula. In the right posterior fusiform gyrus and the left lingual gyrus, the correlation between the pairwise similarity in activity patterns evoked by words and the pairwise distance in valence and concreteness was modulated by the direction of attention, word valence or concreteness. The data indicate that orienting attention to basic dimensions of word meaning exerts effects on the representation of word meaning in more peripheral nodes, such as the ventral occipital cortex, rather than the core perisylvian language regions.

A Reverse Stroop Task with Mouse Tracking.

In a reverse Stroop task, observers respond to the meaning of a color word irrespective of the color in which the word is printed—for example, the word red may be printed in the congruent color (red), an incongruent color (e.g., blue), or a neutral color (e.g., white). Although reading of color words in this task is often thought to be neither facilitated by congruent print colors nor interfered with incongruent print colors, this interference has been detected by using a response method that does not give any bias in favor of processing of word meanings or processing of print colors. On the other hand, evidence for the presence of facilitation in this task has been scarce, even though this facilitation is theoretically possible. By modifying the task such that participants respond to a stimulus color word by pointing to a corresponding response word on a computer screen with a mouse, the present study investigated the possibility that not only interference but also facilitation would take place in a reverse Stroop task. Importantly, in this study, participants’ responses were dynamically tracked by recording the entire trajectories of the mouse. Arguably, this method provided richer information about participants’ performance than traditional measures such as reaction time and accuracy, allowing for more detailed (and thus potentially more sensitive) investigation of facilitation and interference in the reverse Stroop task. These trajectories showed that the mouse’s approach toward correct response words was significantly delayed by incongruent print colors but not affected by congruent print colors, demonstrating that only interference, not facilitation, was present in the current task. Implications of these findings are discussed within a theoretical framework in which the strength of association between a task and its response method plays a critical role in determining how word meanings and print colors interact in reverse Stroop tasks.

Contributions of emotional state and attention to the processing of syntactic agreement errors: evidence from P600.

The classic account of language is that language processing occurs in isolation from other cognitive systems, like perception, motor action, and emotion. The central theme of this paper is the relationship between a participant’s emotional state and language comprehension. Does emotional context affect how we process neutral words? Recent studies showed that processing of word meaning – traditionally conceived as an automatic process – is affected by emotional state. The influence of emotional state on syntactic processing is less clear. One study reported a mood-related P600 modulation, while another study did not observe an effect of mood on syntactic processing. The goals of this study were: First, to clarify whether and if so how mood affects syntactic processing. Second, to shed light on the underlying mechanisms by separating possible effects of mood from those of attention on syntactic processing. Event-related potentials (ERPs) were recorded while participants read syntactically correct or incorrect sentences. Mood (happy vs. sad) was manipulated by presenting film clips. Attention was manipulated by directing attention to syntactic features vs. physical features. The mood induction was effective. Interactions between mood, attention and syntactic correctness were obtained, showing that mood and attention modulated P600. The mood manipulation led to a reduction in P600 for sad as compared to happy mood when attention was directed at syntactic features. The attention manipulation led to a reduction in P600 when attention was directed at physical features compared to syntactic features for happy mood. From this we draw two conclusions: First, emotional state does affect syntactic processing. We propose mood-related differences in the reliance on heuristics as the underlying mechanism. Second, attention can contribute to emotion-related ERP effects in syntactic language processing. Therefore, future studies on the relation between language and emotion will have to control for effects of attention.

Four Practical Principles for Enhancing Vocabulary Instruction

This article presents four practical principles that lead to enhanced word-meaning instruction in the elementary grades. The authors, a collaborative team of researchers and classroom teachers, identified and developed these principles and related instructional activities during a three-year vocabulary instruction research project. The principles include establishing efficient, rich routines for introducing target word meanings; providing review activities that promote deep processing of word meanings; responding directly to student confusion; and fostering universal participation in and accountability for vocabulary instruction. The authors draw on instructional materials, classroom images, and observational data from their research to describe and illustrate each of these strategies.

Embodied Semantic Processing of Chinese Action Idioms: Evidence from fMRI Study

There is mixed evidence concerning the processing of word meaning. Early research into language assumed that word meaning was processed in the left temporal lobe. However, more recent research suggests that words are processed by distributed neuronal assemblies. This fMRI study explores embodied semantic processing and semantic system of Chinese action idioms. In the study, thirteen participants were asked to read one hundred and twenty four-character Chinese idioms, which are related to hand, face, mouth and feet action. Next, the participants were asked to judge whether the idiom's meaning was related to mouth pronunciation. Functional brain imaging was conducted on a Siemens 3.0T scanner while participants performed Go/No go semantic judgment tasks. Imaging data were processed by spm8 software. Multi-comparison tests were conducted between the scores of the semantic comprehension task under four conditions(hand idioms, face idioms, mouth idioms and feet idioms). The activation was corrected by AlphaSim at the threshold of p0.001 and cluster size 39. The brain systems which are engaged in the processing of action idioms related to body parts were tested and Marsbar software was used to create images of the relevant areas of the cortex. The result showed:(1) when comparing activations for face and mouth idioms with activations for hand and feet idioms, more activations were observed for face and mouth idioms in the bilateral parietal lobe, precentral gyrus, postcentral gyrus, the dorsal premotor of the middle frontal gyrus and superior frontal gyrus, and inferior temporal gyrus; hand idioms caused more activation in the posterior of inferior parietal lobe bilaterally, inferiorfrontal gyrus in anterior part of premotor cortex, and middle frontal gyrus and in the dorsal of the premotor cortex; more activations were observed for feet idioms compared to hand idioms in dorsal along the midline and superior parietal lobe.(2) There were more activations for face and mouth idioms in the bilateral occipital lobe, the left dorsal premotor of the middle frontal gyrus and superior frontal gyrus, the pars triangularis in the inferior frontal gyrus and BA47, and in the left lingual gyrus when compared to hand and feet idioms. Superior frontal and middle frontal region of BA8 are activated to a greater extent for face idioms as opposed to mouth idioms. Mouth idioms specifically activated the left Broca and BA47.(3) Chinese action idioms activated prefrontal cortex, parietal lobe, occipital lobe and temporal lobe. But some differences were observed in activation between these regions. More activation was observed in parietal lobe for hand and feet idioms than face and mouth idioms. Face and mouth idioms were found to generate more activation in the occipital cortex than hand and feet idioms. This finding confirmed that the prefrontal-parietal-temporal network is the constitution of semantic system. The embodied semantics theory, states that verb meaning is represented in the cortex within the same sensory motor circuitry which executes the action. The cortex activation induced by Chinese action idioms in frontal-parietal lobe engaged action execution, and this pattern is consistent with the hypothesis of embodied semantics comprehension theory which indicates that semantic representation on imageable verbs is correlated with the somatotopic activation of motor and premotor cortex. The results demonstrate that semantic comprehension of Chinese action idioms is affected by our experience.

Validating the truth of propositions: behavioral and ERP indicators of truth evaluation processes

We investigated processes of truth validation during reading. Participants responded to 'true' and 'false' probes after reading simple true or false sentences. Compatible sentence/probe combinations (true/'true', false/'false') facilitated responding compared with incompatible combinations (true/'false', false/'true'), indicating truth validation. Evidence for truth validation was obtained after inducing an evaluative mindset but not after inducing a non-evaluative mindset, using additional intermixed tasks requiring true/false decisions or sentence comparisons, respectively. Event-related potentials revealed an increased late negativity (500-1000 ms after onset of the last word of sentences) for false compared with true sentences. Paralleling behavioral results, this electroencephalographic marker only obtained in the evaluative mindset condition. Further, mere semantic mismatches between subject and object of sentences led to an elevated N400 for both mindset conditions. Taken together, our findings suggest that truth validation is a conditionally automatic process that is dependent on the current task demands and resulting mindset, whereas the processing of word meaning and semantic relations between words proceeds in an unconditionally automatic fashion.

The Relationship of Language and Emotion: N400 Support for an Embodied View of Language Comprehension

According to embodied theories, the symbols used by language are meaningful because they are grounded in perception, action, and emotion. In contrast, according to abstract symbol theories, meaning arises from the syntactic combination of abstract, amodal symbols. If language is grounded in internal bodily states, then one would predict that emotion affects language. Consistent with this, advocates of embodied theories propose a strong link between emotion and language [Havas, D., Glenberg, A. M., & Rinck, M. Emotion simulation during language comprehension. Psychonomic Bulletin & Review, 14, 436-441, 2007; Niedenthal, P. M. Embodying emotion. Science, 316, 1002-1005, 2007]. The goal of this study was to test abstract symbol vs. embodied views of language by investigating whether mood affects semantic processing. To this aim, we induced different emotional states (happy vs. sad) by presenting film clips that displayed fragments from a happy movie or a sad movie. The clips were presented before and during blocks of sentences in which the cloze probability of mid-sentence critical words varied (high vs. low). Participants read sentences while ERPs were recorded. The mood induction procedure was successful: Participants watching the happy film clips scored higher on a mood scale than those watching the sad clips. For N400, mood by cloze probability interactions were obtained. The N400 cloze effect was strongly reduced in the sad mood compared with the happy mood condition. Furthermore, a difference in late positivity was only present for the sad mood condition. The mood by semantic processing interaction observed for N400 supports embodied theories of meaning and challenges abstract symbol theories that assume that processing of word meaning reflects a modular process.

Affective Priming Effects of Musical Sounds on the Processing of Word Meaning

Recent studies have shown that music is capable of conveying semantically meaningful concepts. Several questions have subsequently arisen particularly with regard to the precise mechanisms underlying the communication of musical meaning as well as the role of specific musical features. The present article reports three studies investigating the role of affect expressed by various musical features in priming subsequent word processing at the semantic level. By means of an affective priming paradigm, it was shown that both musically trained and untrained participants evaluated emotional words congruous to the affect expressed by a preceding chord faster than words incongruous to the preceding chord. This behavioral effect was accompanied by an N400, an ERP typically linked with semantic processing, which was specifically modulated by the (mis)match between the prime and the target. This finding was shown for the musical parameter of consonance/dissonance (Experiment 1) and then extended to mode (major/minor) (Experiment 2) and timbre (Experiment 3). Seeing that the N400 is taken to reflect the processing of meaning, the present findings suggest that the emotional expression of single musical features is understood by listeners as such and is probably processed on a level akin to other affective communications (i.e., prosody or vocalizations) because it interferes with subsequent semantic processing. There were no group differences, suggesting that musical expertise does not have an influence on the processing of emotional expression in music and its semantic connotations.

ERP predictors of encoding and recognition memory

Event Abstract Back to Event ERP predictors of encoding and recognition memory Olga Marchenko1* 1 Center of Experimental Psychology MCUPE, Russia Congruency effect on encoding and recognition of words was studied. Experiment consisted of learning and test phases. Trials consisted of two words in learning phase. First word was name of some category (prime) and second word belonged to that or another category. Subjects were asked to answer as soon and as accurately as possible if second word belongs to category denoted by prime. Subjects were not aware that memory test will follow. It was shown that behavioural and ERP data for words on learning phase which were remembered later were different from these for words which were forgotten. On a test phase subjects explicitly were instructed to press one key if word was at learning phase in their opinion and press another key if not. Fact of being congruent or incongruent in study phase influenced also recollection on test phase. Thus behavioural and ERP data showed that congruency affected encoding and recognition processes. Events which precede word presentation could influence effectively of its encoding and recollection. When words are primed by name of category, representation of this category is activated which causes deeper processing of word meaning. It causes more effective memorising and recognition of these words. Funding: Supported by RFH Grant 11-36-00314. Keywords: brain oscillations, EEG Conference: XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011. Presentation Type: Poster Presentation Topic: Poster Sessions: Quantitative Analysis of EEG, MEG & Brain Oscillations Citation: Marchenko O (2011). ERP predictors of encoding and recognition memory. Conference Abstract: XI International Conference on Cognitive Neuroscience (ICON XI). doi: 10.3389/conf.fnhum.2011.207.00122 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 17 Nov 2011; Published Online: 28 Nov 2011. * Correspondence: Dr. Olga Marchenko, Center of Experimental Psychology MCUPE, Moscow, Russia, olga.marchenko@psyexp.ru Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Olga Marchenko Google Olga Marchenko Google Scholar Olga Marchenko PubMed Olga Marchenko Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Effects of word frequency on semantic memory in schizophrenia: Electrophysiological evidence for a deficit in linguistic access

Background Abnormal storage and/or access are among the hypothesized causes of semantic memory deficit in schizophrenia. Neuropsychological and connectionist models have emphasized functional systems that serve the processing of word meaning and frequency: semantic storage disturbance is presumed to result from weak representations of word meaning; defective access is assumed to result from compromises to pathways that activate word frequency knowledge. Candidate biological systems include neuromodulatory pathways that normally function to enhance neural signals (e.g., cholinergic system). Electrophysiological responding may be informative regarding the storage-access distinction for schizophrenia. Methods Visual event-related potentials were recorded for 14 schizophrenia outpatients receiving atypical antipsychotics, and 14 healthy controls group-matched to patients on age, gender, and demographics. N400 was elicited using an incidental semantic priming paradigm, in which semantic relatedness and word frequency were varied, and a letter probe task. Results Compared to controls, patients showed reduced N400 (µV) discrimination of semantic relatedness. Groups also showed different patterns of N400 to word frequency. Controls' N400 increased in negativity as words decreased in frequency of occurrence, while patients did not show a linear relationship between N400 and word frequency. Groups also differed for N400 to frequently occurring words. Patients exhibited increased negativity to high and very high frequency words, compared to controls. A subgroup of patients receiving antipsychotics with known affinity binding for muscarinic receptors (clozapine and olanzapine) showed significant albeit limited N400 priming, but their N400 to word frequency remained nonsignificant. Conclusions Results suggest a deficit in semantic access for schizophrenia, as well as an influence of neuromodulators on the activation of connections among semantic representations. Cumulative findings indicating only limited N400 priming for patients receiving either typical or atypical antipsychotics support the hypothesis that semantic memory deficit represents a trait marker for schizophrenia.

Intensity in Vocabulary Instruction and Effects on Reading Comprehension

Prior research has shown that vocabulary instruction can enhance the comprehension of passages when instruction includes definitional and contextual information, provides multiple instructional encounters with the words, and requires learners to engage actively in processing of word meanings (M. F.

The effect of frequency of shared features on judgments of semantic similarity

Insight into the structure of conceptual knowledge can be gleaned by examining how statistical regularities in the semantic structure of concepts affect semantic processing. Two similarity judgment experiments revealed that pairs of concepts sharing relatively rare features were judged to be more similar than concepts sharing an equal number of relatively frequent features. Simulations confirmed that these results are consistent with a recurrent connectionist network model of semantic processing in which units corresponding to rare features are activated more quickly and accurately than units corresponding to frequent features. These results support the hypothesis that rare features play a privileged role in the processing of word meanings.

Left-frontal brain potentials index conceptual implicit memory for words initially viewed subliminally

Neural correlates of explicit and implicit memory tend to co-occur and are therefore difficult to measure independently, posing problems for understanding the unique nature of different types of memory processing. To circumvent this problem, we developed an experimental design wherein subjects acquired information from words presented in a subliminal manner, such that conscious remembering was minimized. Cross-modal word repetition was used so that perceptual implicit memory would also be limited. Healthy human subjects viewed subliminal words six times each and about 2 min later heard the same words interspersed with new words in a category-verification test. Electrophysiological correlates of word repetition included negative brain potentials over left-frontal locations beginning approximately 500 ms after word onset. Behavioral responses were slower for repeated words than for new words. Differential processing of word meaning in the absence of explicit memory was most likely responsible for differential electrical and behavioral responses to old versus new words. Moreover, these effects were distinct from neural correlates of explicit memory observed in prior experiments, and were observed here in two separate experiments, thus providing a foundation for further investigations of relationships and interactions between different types of memory engaged when words repeat.

Vocabulary Intervention for Kindergarten Students: Comparing Extended Instruction to Embedded Instruction and Incidental Exposure

The purpose of the two studies reported in this article was to evaluate the effectiveness of extended vocabulary instruction during storybook reading with kindergarten students within a small-group intervention setting. Extended vocabulary instruction is characterized by explicit teaching that includes both contextual and definitional information, multiple exposures to target words in varied contexts, and experiences that promote deep processing of word meanings. In Study One, we compared extended instruction of target words to incidental exposure. In Study Two, we compared extended instruction to embedded instruction (i.e., providing simple definitions within the context of the story). Our findings indicated that extended instruction resulted in greater word learning than either incidental exposure or embedded instruction. Moreover, students maintained much of their understanding of word meanings six to eight weeks after instruction. Implications are discussed in relation to a tri-level approach to vocabulary instruction and intervention for kindergarten students at risk for language and reading disabilities.

Evidence for several components of word familiarity

Familiarity with a word can be divided into two main components: familiarity with the form of the word (due to both its lexicality and its specific form) and familiarity with its meaning. In this study, ratings of familiarity were compared for words whose meaning was unknown to participants (UM words), for words of known meaning (KM words), and for unknown words (U words). Linguistic and experiential frequencies were equivalent. Rated familiarity was lower for UM than KM words and even lower for U words. Next, we built pseudowords from these stimuli by changing one letter and submitted them to two familiarity rating tasks that differed in the nature of the additional stimuli: either only nonwords or nonwords plus words. It was assumed that familiarity ratings would be lower for pseudowords built from UM words than for pseudowords built from KM words. The data were consistent with this assumption, and ratings depended on the initial categories of stimuli. These results support the view that usual word familiarity has two components, familiarity with form and familiarity with meaning, and a double source, processing of word form and processing of word meaning. The full set of these materials and norms may be downloaded from www.psychonomic.org/archive.

Neuroimaging Reveals Automatic Speech Coding during Perception of Written Word Meaning

The extent to which visual word perception engages speech codes (i.e., phonological recoding) remains a crucial question in understanding mechanisms of reading. In this study, we used functional magnetic resonance imaging techniques combined with behavioral response measures to examine neural responses to focused versus incidental phonological and semantic processing of written words. Three groups of subjects made simple button-pressing responses in either phonologically (rhyming-judgment) or semantically (category-judgment) focused tasks or both tasks with identical sets of visual stimuli. In the phonological tasks, subjects were given both words and pseudowords separated in different scan runs. The baseline task required feature search of scrambled letter strings created from the stimuli for the experimental conditions. The results showed that cortical regions associated with both semantic and phonological processes were strongly activated when the task required active processing of word meaning. However, when subjects were actively processing the speech sounds of the same set of written words, brain areas typically engaged in semantic processing became silent. In addition, subjects who performed both the rhyming and the semantic tasks showed diverse and significant bilateral activation in the prefrontal, temporal, and other brain regions. Taken together, the pattern of brain activity provides evidence of a neural basis supporting the theory that in normal word reading, phonological recoding is automatic and facilitates semantic processing of written words, while rapid comprehension of word meaning requires devoted attention. These results also raise questions about including multiple cognitive tasks in the same neuroimaging sessions.

Neuroimaging Reveals Automatic Speech Coding during Perception of Written Word Meaning

The extent to which visual word perception engages speech codes (i.e., phonological recoding) remains a crucial question in understanding mechanisms of reading. In this study, we used functional magnetic resonance imaging techniques combined with behavioral response measures to examine neural responses to focused versus incidental phonological and semantic processing of written words. Three groups of subjects made simple button-pressing responses in either phonologically (rhyming-judgment) or semantically (category-judgment) focused tasks or both tasks with identical sets of visual stimuli. In the phonological tasks, subjects were given both words and pseudowords separated in different scan runs. The baseline task required feature search of scrambled letter strings created from the stimuli for the experimental conditions. The results showed that cortical regions associated with both semantic and phonological processes were strongly activated when the task required active processing of word meaning. However, when subjects were actively processing the speech sounds of the same set of written words, brain areas typically engaged in semantic processing became silent. In addition, subjects who performed both the rhyming and the semantic tasks showed diverse and significant bilateral activation in the prefrontal, temporal, and other brain regions. Taken together, the pattern of brain activity provides evidence of a neural basis supporting the theory that in normal word reading, phonological recoding is automatic and facilitates semantic processing of written words, while rapid comprehension of word meaning requires devoted attention. These results also raise questions about including multiple cognitive tasks in the same neuroimaging sessions.