Experiments on non-native phonemic contrast learning typically use either lexical or perceptual training. However, few studies have compared their efficiency using comparable protocols. In our previous study (Pattamadilok, Welby, & Tyler, 2022), we applied a lexical training protocol to examine the contribution of articulatory and orthographic cues to new word learning. Native speakers of French were trained to associate unknown objects with minimal-pairs of new English pseudowords differing in the initial /f/ versus /θ/ phoneme, a contrast that does not exist in French (e.g., fedge, thedge). The presence of an orthographic cue during training led to an overnight improvement of both retention of new word-object associations and the ability to perceive the /f/-/θ/ contrast. Here, we employed the same material and assessment tasks while employing perceptual, rather than lexical training; that is, the visual cues were presented during a phoneme discrimination training. The benefits of the visual cues differed from those of the initial study. While both articulatory and orthographic cues enhanced phoneme discrimination ability during the training phase, only the articulatory cue yielded an overnight improvement in perceptual ability without generalizing this benefit to the retention of word-object associations. Together, these two datasets demonstrate that, even in well-matched experimental protocols, different training methods can yield distinct learning outcomes. Optimal training protocols must consider the complex interplay between the level of language representations targeted by the training, the differential benefits of input modality, and the short- versus long-term training effects on different processing levels.
Reading acquisition requires linking visual symbols with speech sounds, leading to the development of neural sensitivity to print. While prior studies have shown the importance of cross-modal integration in spoken language areas, the higher-level visual area (lvOT) processing printed words remained more context-dependent. This longitudinal study investigated whether the lvOT undergoes cross-modal reorganization to facilitate print-speech integration during reading development and how these changes relate to reading skills. We followed children over two years, beginning at the onset of formal reading instruction. We examine lvOT responses to print-specific, speech-specific, and its convergence at whole-brain, region of interest, and voxel-based levels. Results showed that with reading experience, the initial print-specific responses in the lvOT are transformed into responses to both print and speech input. This transformation positively correlates with reading skills, especially in early stages of reading acquisition. These findings suggest that reading acquisition drives cross-modal reorganization within the lvOT, enabling the area to integrate print and speech. They shed light on the broader neural mechanisms supporting reading development.
Reading relies on the ability to map written symbols with speech sounds. A specific part of the left ventral occipitotemporal cortex, known as the Visual Word Form Area (VWFA), plays a crucial role in this process. Through the automatization of the mapping ability, this area progressively becomes specialized in written word recognition. Yet, despite its key role in reading, the area also responds to speech. This observation raises questions about the actual nature of neural representations encoded in the VWFA and, therefore, the underlying mechanism of the cross-modal responses. Here, we addressed this issue by applying fine-grained analyses of within- and cross-modal repetition suppression effects (RSEs) and Multi-Voxel Pattern Analyses in fMRI and sEEG experiments. Convergent evidence across analysis methods and protocols showed significant RSEs and successful decoding in both within-modal visual and auditory conditions, suggesting that populations of neurons within the VWFA distinctively encode written and spoken language. This functional organization of neural populations enables the area to respond to both written and spoken inputs. The finding opens further discussions on how the human brain may be prepared and adapted for an acquisition of a complex ability such as reading.
Learning to read changes the nature of speech representations. One possible change consists in transforming phonological representations into phonographic ones. However, evidence for such transformation remains surprisingly scarce. Here, we used a novel word learning paradigm to address this issue. During the learning phase, participants learned unknown words in both spoken and written forms. Following this phase, the impact of spelling knowledge on the auditory perception of the novel words was assessed at two time points through an unattended oddball paradigm, while the Mismatch Negativity component was measured by high density EEG. Immediately after the learning phase, no influence of spelling knowledge on the perception of the spoken input was found. Interestingly, one week later, this influence emerged, making similar sounding words with different spellings more distinct than similar sounding words that also shared the same spelling. Our finding provides novel neurophysiological evidence of an integration of phonological and orthographic representations that occurs once newly acquired knowledge has been consolidated. The resulting ‘phonographic’ representations may characterize how known words are stored in literates’ mental lexicon.
PurposeIn adults with dyslexia (DYS), the persistent influence of phonological deficits on spoken language processing has mainly been examined in either perceptual tasks or those tapping complex cognitive operations. Much less attention is devoted to spoken word recognition per se. Our study aimed to fill this gap.MethodAdults with and without dyslexia (for both groups: N = 30, mean age = 21 years, 50% female, 100% white European) performed an auditory lexical decision task. Performance and ERP were recorded.ResultsReaction times showed a lexicality effect in both groups although they differed in ERP responses to stimulus lexicality. Skilled readers showed the typical amplitude enhancement for pseudowords compared to words in a late phase of N400 (414-581msec) whereas DYS showed the opposite pattern in an earlier phase of N400 (246-413msec). Both groups showed a stronger negativity during pseudowords processing in the late post-lexical stage (582-800msec).ConclusionsERP data showed subtle differences between the two populations during the lexical stage of word recognition despite their comparable behavioral outcomes. We hypothesized that a stronger reliance on intact semantic knowledge might contribute to the general enhanced and sustained ERP responses to words in DYS across different phases of lexical processing, although confirmation is needed.
Reading relies on the ability to map written symbols with speech sounds. The left ventral occipitotemporal cortex (left-vOT) plays a crucial role in this process. Through the automatization of the mapping ability, this specific part of the ventral visual pathway (a.k.a., the Visual Word Form Area) progressively becomes specialized in written word recognition. Yet, despite its key role in reading, the area also responds to speech. This observation raises questions about the actual nature of neural representations encoded in the left-vOT and, therefore, the underlying mechanism of the cross-modal responses. Here, we addressed this issue by applying fine-grained analyses of within- and cross-modal repetition suppression effects (RSEs) and Multi-Voxel Pattern Analyses in fMRI and sEEG experiments. Convergent evidence across analysis methods and protocols showed significant RSEs and successful decoding in both within-modal visual and auditory conditions suggesting that subpopulations of neurons within the left-vOT distinctly encode written and spoken language inputs. This functional organization of neural populations enables the area to respond to speech input directly and indirectly, i.e., after speech sounds are converted to orthographic representations. The finding opens further discussions on how the human brain may be prepared and adapted for an acquisition of a complex ability such as reading. ### Competing Interest Statement The authors have declared no competing interest.
Learning to read changes the nature of speech representation. One possible change consists in transforming phonological representations into phonographic ones. However, evidence for such transformation remains surprisingly scarce. Here, we used a novel word learning paradigm to address this issue. During a learning phase, participants were exposed to unknown words in both spoken and written forms. Following this phase, the impact of spelling knowledge on spoken input perception was assessed at two time points through an unattended oddball paradigm, while the Mismatch Negativity component was measured by high density EEG. Immediately after the learning phase, no influence of spelling knowledge on the perception of the spoken input was found. Interestingly, one week later, this influence emerged, making similar sounding words with different spellings more distinct than similar sounding words that also share the same spelling. Our finding provides novel neurophysiological evidence of an integration of phonological and orthographic representations that occurs once newly acquired knowledge has been consolidated. These novel phonographic representations may characterize how known words are stored in literates’ mental lexicon. ### Competing Interest Statement The authors have declared no competing interest.
As an interface between the visual and language system, the left ventral occipito-temporal cortex (left-vOT) plays a key role in reading. This functional role is supported by anatomical and functional connections between the area and other brain regions within and outside the language network. Nevertheless, only a few studies have investigated how the functional state of this area, which is dependent upon the nature of the task demand and the stimulus being processed, could influence the activity of the connected brain regions. In the present combined TMS-EEG study, we studied the left-vOT effective connectivity by adopting a direct, causal intervention approach. Using TMS, we probed left-vOT activation in different processing contexts and measured the neural propagation of activity from this area to other brain regions. A comparison of neural propagation measured during low-level visual detection of language versus non-language stimuli showed that processing language stimuli reduced neural propagation from the left-vOT to the right occipital cortex. Additionally, compared to the low-level visual detection of language stimuli, performing semantic judgments on the same stimuli further reduced neural propagation to the posterior part of the corpus callosum, right superior parietal lobule and the right anterior temporal lobe. This reduction of cross-hemispheric neural propagation was accompanied by an increase in the collaboration between areas within the left-hemisphere language network. Together, this first evidence from a direct causal intervention approach suggests that processing language stimuli and performing a high-level language task reduce effective connectivity from the left-vOT to the right hemisphere, and may contribute to the left-hemisphere lateralization typically observed during language processing.
Brain lateralization of lexical tone processing remains a matter of debate. In this study we used a dichotic listening paradigm to examine the influences of the knowledge of Jyutping (a romanization writing system which provides explicit Cantonese tone markers), linguistic-processing demand and tone type on the ear preference pattern of native tone processing in Hong Kong Cantonese speakers. While participants with little knowledge of Jyutping showed a previously reported left-ear advantage (LEA), those with a good level of Jyutping expertise exhibited either a right-ear advantage or bilateral processing during lexical tone identification and contour tone discrimination, respectively. As for the effect of linguistic-processing demand, while an LEA was found in acoustic/phonetic perception situations, this advantage disappeared and was replaced by a bilateral pattern in conditions that involved a greater extent of linguistic processing, suggesting an increased involvement of the left hemisphere. Regarding the effect of tone type, both groups showed an LEA in level tone discrimination, but only the Jyutping group demonstrated a bilateral pattern in contour tone discrimination. Overall, knowledge of written codes of tones, greater degree of linguistic processing and contour tone processing seem to influence the brain lateralization of lexical tone processing in native listeners of Cantonese by increasing the recruitment of the left-hemisphere language network.
The left ventral occipito-temporal cortex (left-vOT) plays a key role in reading. Interestingly, the area also responds to speech input, suggesting that it may have other functions beyond written word recognition. Here, we adopt graph theoretical analysis to investigate the left-vOT’s functional role in the whole-brain network while participants process spoken sentences in different contexts. Overall, different connectivity measures indicate that the left-vOT acts as an interface enabling the communication between distributed brain regions and sub-networks. During simple speech perception, the left-vOT is systematically part of the visual network and contributes to the communication between neighboring areas, remote areas, and sub-networks, by acting as a local bridge, a global bridge, and a connector, respectively. However, when speech comprehension is explicitly required, the specific functional role of the area and the sub-network to which the left-vOT belongs change and vary with the quality of speech signal and task difficulty. These connectivity patterns provide insightful information on the contribution of the left-vOT in various contexts of language processing beyond its role in reading. They advance our general understanding of the neural mechanisms underlying the flexibility of the language network that adjusts itself according to the processing context.
The left ventral occipito-temporal cortex (left-vOT) plays a key role in reading. Several studies have also reported its activation during speech processing, suggesting that it may play a role beyond written word recognition. Here, we adopt a graph theoretical analysis to investigate the functional role of this area in the whole-brain network while participants processed spoken sentences in different tasks. We find that its role and interactions with other areas changes in an adaptive manner. In a low-level speech perception task, the left-vOT is part of the visual network and acts as a connector that supports the communication with other cognitive systems. When speech comprehension is required, the area becomes a connector within the sensorimotor-auditory network typically recruited during speech processing. However, when comprehension is compromised due to degradation of speech input, the area disengages from the sensorimotor-auditory network. It becomes part of the visual network again and turns from connector into a simple peripheral node. These varying connectivity patterns are coherent with the Interactive Account considering the left-vOT as a convergent zone with multiple functions and interaction patterns that depend on task demands and the nature of sensory input.
Auditory speech appears to be linked to visual articulatory gestures and orthography through different mechanisms. Yet, both types of visual information have a strong influence on speech processing. The present study directly compared their contributions to speech processing using a novel word learning paradigm. Native speakers of French, who were familiar with English, learned minimal pairs of novel English words containing the English /θ/-/f/ phonemic contrast under one of three exposure conditions: (a) the auditory forms of novel words alone, (b) the auditory forms associated with articulatory gestures, or (c) the auditory forms associated with orthography. The benefits of the three methods were compared during training and at two posttraining time points where the visual cues were no longer available. We also assessed participants' auditory-only discrimination of the /θ/-/f/ contrast pretraining and posttraining. During training, the visual cues facilitated novel word learning beyond the benefit of the auditory input alone. However, these additional benefits did not persist when participants' discrimination and novel word learning performance were assessed immediately after training. Most interestingly, after a night's sleep, participants who were exposed to orthography during training showed significant improvement in both discrimination and novel word learning compared to the previous day. The findings are discussed in terms of online versus residual impacts of articulatory gestures and orthography on speech processing. While both visual cues are beneficial when they are simultaneously presented with speech, only orthography shows residual impacts leading to a sleep-dependent enhancement of lexical knowledge through memory consolidation and retuning of the second language /θ/-/f/ contrast. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
The acquisition of an alphabetic orthography transforms speech processing in the human brain. Behavioral evidence shows that phonological awareness as assessed by meta-phonological tasks like phoneme judgment, is enhanced by alphabetic literacy acquisition. The current study investigates the time-course of the neuro-cognitive operations underlying this enhancement as revealed by event-related potentials (ERPs). Chinese readers with and without proficiency in Jyutping , a Romanization system of Cantonese, were recruited for an auditory onset phoneme judgment task; their behavioral responses and the elicited ERPs were examined. Proficient readers of Jyutping achieved higher response accuracy and exhibited more negative-going ERPs in three early ERP time-windows corresponding to the P1, N1, and P2 components. The phonological mismatch negativity component exhibited sensitivity to both onset and rhyme mismatch in the speech stimuli, but it was not modulated by alphabetic literacy skills. The sustained negativity in the P1-N1-P2 time-windows is interpreted as reflecting enhanced phonetic/phonological processing or attentional/awareness modulation associated with alphabetic literacy and phonological awareness skills.
Abstract An event-related functional magnetic resonance imaging study examined how speakers inspect their own speech for errors. Concretely, we sought to assess 1) the role of the temporal cortex in monitoring speech errors, linked with comprehension-based monitoring; 2) the involvement of the cerebellum in internal and external monitoring, linked with forward modeling; and 3) the role of the medial frontal cortex for internal monitoring, linked with conflict-based monitoring. In a word production task priming speech errors, we observed enhanced involvement of the right posterior cerebellum for trials that were correct, but on which participants were more likely to make a word as compared with a nonword error (contrast of internal monitoring). Furthermore, comparing errors to correct utterances (contrast of external monitoring), we observed increased activation of the same cerebellar region, of the superior medial cerebellum, and of regions in temporal and medial frontal cortex. The presence of the cerebellum for both internal and external monitoring indicates the use of forward modeling across the planning and articulation of speech. Dissociations across internal and external monitoring in temporal and medial frontal cortex indicate that monitoring of overt errors is more reliant on vocal feedback control.
Both visual articulatory gestures and orthography provide information on the phonological content of speech. This EEG study investigated the integration between speech and these two visual inputs. A comparison of skilled readers' brain responses elicited by a spoken word presented alone versus synchronously with a static image of a viseme or a grapheme of the spoken word's onset showed that while neither visual input induced audiovisual integration on N1 acoustic component, both led to a supra-additive integration on P2, with a stronger integration between speech and graphemes on left-anterior electrodes. This pattern persisted in P350 time-window and generalized to all electrodes. The finding suggests a strong impact of spelling knowledge on phonetic processing and lexical access. It also indirectly indicates that the dynamic and predictive value present in natural lip movements but not in static visemes is particularly critical to the contribution of visual articulatory gestures to speech processing.
A question under debate in psycholinguistics is the nature of the relationship between spoken and written languages. Although it has been extensively shown that orthographic transparency, which varies across writing systems, strongly affects reading performance, its role in speech processing is much less investigated. The present study addressed this issue in Persian, whose writing system provides a possibility to assess the impact of orthographic transparency on spoken word recognition in young children at different stages of reading acquisition. In Persian, the long vowels are systematically present in the script, whereas the spelling correspondence of short vowels is progressively omitted from the script in the course of reading acquisition, thus, turning transparent into opaque spelling. Based on this unique characteristic, we tested 144 monolingual Persian-speaking nonreaders (i.e., preschoolers) and readers (second graders to fifth graders and young adults) in an auditory lexical decision task using transparent and opaque words. Overall, the results showed that, in accordance with the fact that the diacritics of short vowels are progressively omitted during the second year of schooling, the stimuli containing short vowels (opaque words) were recognized more slowly than transparent ones in third graders. Interestingly, there is a hint that the emergence of the transparency effect in the third graders was associated with an overall slower recognition speed in this group compared to their younger peers. These findings indicate that learning opaque spelling-sound correspondence might not only generate interference between the two language codes but also induce a general processing cost in the entire spoken language system.
An fMRI study examined how speakers inspect their own speech for errors. In a word production task, we observed enhanced involvement of the right posterior cerebellum for trials that were correct, but on which participants were more likely to make a word-as compared to a non-word error. Furthermore, comparing errors to correctly produced utterances, we observed increased activation of the same cerebellar region, in addition to temporal and medial frontal regions. Within the framework associating the cerebellum to forward modelling of upcoming actions, this indicates that forward models of verbal actions contain information about word representations used for error monitoring even before articulation (internal monitoring). Additional resources relying on speech perception and conflict monitoring are deployed during articulation to detect overt errors (external monitoring). In summary, speech monitoring seems to recruit a network of brain regions serving domain general purposes, even for abstract levels of processing.
In skilled adult readers, reading words is generally assumed to rapidly and automatically activate the phonological code. In adults with dyslexia, despite the main consensus on their phonological processing deficits, little is known about the activation time course of this code. The present study investigated this issue in both populations. Participants' accuracy and eye movements were recorded while they performed a visual lexical decision task in which phonological consistency of written words was manipulated. Readers with dyslexia were affected by phonological consistency during second fixation duration of visual word recognition suggesting a late activation of the phonological code. Regarding skilled readers, no influence of phonological consistency was found when the participants were considered a homogeneous population. However, a different pattern emerged when they were divided into two subgroups according to their phonological and semantic abilities: Those who showed better decoding than semantic skills were affected by phonological consistency at the earliest stage of visual word recognition while those who showed better semantic than decoding skills were not affected by this factor at any processing stage. Overall, the findings suggest that the presence of phonological deficits in readers with dyslexia is associated with a delayed activation of phonological representations during reading. In skilled readers, the contribution of phonology varies with their reading profile, i.e., being phonologically or semantically oriented.
The left ventral occipitotemporal cortex (vOT) is considered the key area of the visuo-orthographic system. However, some studies reported that the area is also involved in speech processing tasks, especially those that require activation of orthographic knowledge. These findings suggest the existence of a top-down activation mechanism allowing such cross-modal activation. Yet, little is known about the involvement of the vOT in more natural speech processing situations like spoken sentence processing. Here, we addressed this issue in a functional Magnetic Resonance Imaging (fMRI) study while manipulating the impacts of two factors, i.e., task demands (semantic vs. low-level perceptual task) and the quality of speech signals (sentences presented against clear vs. noisy background). Analyses were performed at the levels of whole brain and region-of-interest (ROI) focusing on the vOT voxels individually identified through a reading task. Whole brain analysis showed that processing spoken sentences induced activity in a large network including the regions typically involved in phonological, articulatory, semantic and orthographic processing. ROI analysis further specified that a significant part of the vOT voxels that responded to written words also responded to spoken sentences, thus, suggesting that the same area within the left occipitotemporal pathway contributes to both reading and speech processing. Interestingly, both analyses provided converging evidence that vOT responses to speech were sensitive to both task demands and quality of speech signals: Compared to the low-level perceptual task, activity of the area increased when efforts on comprehension were required. The impact of background noise depended on task demands. It led to a decrease of vOT activity in the semantic task but not in the low-level perceptual task. Our results provide new insights into the function of this key area of the reading network, notably by showing that its speech-induced top-down activation also generalizes to ecological speech processing situations.
The phonetic characteristics of French-accented speech suggest that French native speakers often have difficulty producing dental fricatives in English. However, there is a surprising lack of empirical research on perception of those consonants. Canadian French speakers appear to assimilate /θ/ to /t/ and /ð/ to /d/, but loanword evidence suggests that European French speakers should assimilate them to /s/ and /z/, respectively. To test this, 151 native European French listeners categorised and rated the goodness-of-fit of English /θ, f, s, t, ð, v, z, d/ to French phonological categories. /θ/ was categorised as /f/, whereas /ð/ was uncategorised, with responses divided between /v/ and /z/. The remaining consonants were categorised as their corresponding French categories, with /θ/ rated as a poorer French /f/ than /f/. While the majority of individual participants categorised the dental fricatives as /f, v/, there were small subsets of participants who categorised them as /s, z/.