Stem Tones Pre-activate Suffixes in the Brain

Neurophysiological signatures of prediction in language: A critical review of anticipatory negativities

Recent event-related potential (ERP) studies in language comprehension converge in finding anticipatory negativities preceding words or word segments that can be pre-activated based on either sentence contexts or phonological cues. We review these findings from different paradigms in the light of evidence from other cognitive domains in which slow negative potentials have long been associated with anticipatory processes and discuss their potential underlying mechanisms. We propose that this family of anticipatory negativities captures common mechanisms associated with the pre-activation of linguistic information both within words and within sentences. Future studies could utilize these anticipatory negativities in combination with other, well-established ERPs, to simultaneously track prediction-related processes emerging at different time intervals (before and after the perception of pre-activated input) and with distinct time courses (shorter-lived and longer-lived cognitive operations).

Swift Prosodic Modulation of Lexical Access: Brain Potentials From Three North Germanic Language Varieties

PURPOSE

According to most models of spoken word recognition, listeners probabilistically activate a set of lexical candidates, which is incrementally updated as the speech signal unfolds. Speech carries segmental (speech sound) as well as suprasegmental (prosodic) information. The role of the latter in spoken word recognition is less clear. We investigated how suprasegments (tone and voice quality) in three North Germanic language varieties affected lexical access by scrutinizing temporally fine-grained neurophysiological effects of lexical uncertainty and information gain.

METHOD

Three event-related potential (ERP) studies were reanalyzed. In all varieties investigated, suprasegments are associated with specific word endings. Swedish has two lexical "word accents" realized as pitch falls with different timings across dialects. In Danish, the distinction is in voice quality. We combined pronunciation lexica and frequency lists to calculate estimates of lexical uncertainty about an unfolding word and information gain upon hearing a suprasegmental cue and the segment upon which it manifests. We used single-trial mixed-effects regression models run every 4 ms.

RESULTS

Only lexical uncertainty showed solid results: a frontal effect at 150-400 ms after suprasegmental cue onset and a later posterior effect after 200 ms. While a model including only segmental information mostly performed better, it was outperformed by the suprasegmental model at 200-330 ms at frontal sites.

CONCLUSIONS

The study points to suprasegmental cues contributing to lexical access over and beyond segments after around 200 ms in the North Germanic varieties investigated. Furthermore, the findings indicate that a previously reported "pre-activation negativity" predominantly reflects forward-looking processing.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25016486.

Processing of Grammatical Agreement in the Face of Variation in Lexical Stress: A Mismatch Negativity Study

Previous electroencephalography studies have yielded evidence for automatic processing of syntax and lexical stress. However, these studies looked at both effects in isolation, limiting their generalizability to everyday language comprehension. In the current study, we investigated automatic processing of grammatical agreement in the face of variation in lexical stress. Using an oddball paradigm, we measured the Mismatch Negativity (MMN) in Dutch-speaking participants while they listened to Dutch subject-verb sequences (linguistic context) or acoustically similar sequences in which the subject was replaced by filtered noise (nonlinguistic context). The verb forms differed in the inflectional suffix, rendering the subject-verb sequences grammatically correct or incorrect, and leading to a difference in the stress pattern of the verb forms. We found that the MMNs were modulated in both the linguistic and nonlinguistic condition, suggesting that the processing load induced by variation in lexical stress can hinder early automatic processing of grammatical agreement. However, as the morphological differences between the verb forms correlated with differences in number of syllables, an interpretation in terms of the prosodic structure of the sequences cannot be ruled out. Future research is needed to determine which of these factors (i.e., lexical stress, syllabic structure) most strongly modulate early syntactic processing.

Early neuro-electric indication of lexical match in English spoken-word recognition

We investigated early electrophysiological responses to spoken English words embedded in neutral sentence frames, using a lexical decision paradigm. As words unfold in time, similar-sounding lexical items compete for recognition within 200 milliseconds after word onset. A small number of studies have previously investigated event-related potentials in this time window in English and French, with results differing in direction of effects as well as component scalp distribution. Investigations of spoken-word recognition in Swedish have reported an early left-frontally distributed event-related potential that increases in amplitude as a function of the probability of a successful lexical match as the word unfolds. Results from the present study indicate that the same process may occur in English: we propose that increased certainty of a 'word' response in a lexical decision task is reflected in the amplitude of an early left-anterior brain potential beginning around 150 milliseconds after word onset. This in turn is proposed to be connected to the probabilistically driven activation of possible upcoming word forms.

The predictive function of Swedish word accents

Swedish lexical word accents have been repeatedly said to have a low functional load. Even so, the language has kept these tones ever since they emerged probably over a thousand years ago. This article proposes that the primary function of word accents is for listeners to be able to predict upcoming morphological structures and narrow down the lexical competition rather than being lexically distinctive. Psycho- and neurophysiological evidence for the predictive function of word accents is discussed. A novel analysis displays that word accents have a facilitative role in word processing. Specifically, a correlation is revealed between how much incorrect word accents hinder listeners' processing and how much they reduce response times when correct. Finally, a dual-route model of the predictive use of word accents with distinct neural substrates is put forth.

Native language experience shapes pre-attentive foreign tone processing and guides rapid memory trace build-up: An ERP study

Language experience, particularly from our native language (L1), shapes our perception of other languages around us. The present study examined how L1 experience moulds the initial processing of foreign (L2) tone during acquisition. In particular, we investigated whether learners were able to rapidly forge new neural memory traces for novel tonal words, which was tracked by recording learners’ ERP responses during two word acquisition sessions. We manipulated the degree of L1–L2 familiarity by comparing learners with a nontonal L1 (German) and a tonal L1 (Swedish) and by using tones that were similar (fall) or dissimilar (high, low, rise) to those occurring in Swedish. Our results indicate that a rapid, pre‐attentive memory trace build‐up for tone manifests in an early ERP component at ~50 ms but only at particularly high levels of L1–L2 similarity. Specifically, early processing was facilitated for an L2 tone that had a familiar pitch shape (fall) and word‐level function (inflection). This underlines the importance of these L1 properties for the early processing of L2 tone. In comparison, a later anterior negativity related to the processing of the tones’ grammatical content was unaffected by native language experience but was instead influenced by lexicality, pitch prominence, entrenchment, and successful learning. Behaviorally, learning effects emerged for all learners and tone types, regardless of L1–L2 familiarity or pitch prominence. Together, the findings suggest that while L1‐based facilitation effects occur, they mainly affect early processing stages and do not necessarily result in more successful L2 acquisition at behavioral level.

Our findings add important evidence that contributes to answering the open question of how similarity between native and target language influences target language processing and acquisition. We found facilitative effects of similarity only at pre‐attentive levels and only when the degree of similarity was high. Late processing and successful acquisition, on the other hand, were unaffected by the target words’ similarity to native language properties.

Word-initial consonant-vowel coordination in a lexical pitch-accent language

Previous research has acknowledged the effect of prosody on inter-gestural coordination, but specifically the effect of tones is still understudied. This paper has a two-fold purpose. First, it aims to explore effects of the Swedish word accents on word-initial consonant-vowel (CV) coarticulation. Second, it aims to revisit the existing evidence for tonal integration. Based on Articulatory Phonology, it has been suggested that tones - in tone languages - are integrated in the gestural organization of a syllable-initial CV sequence in the same manner as would an additional consonant (CCV), indicated by a time lag between the gestural onsets of the C and the V gesture (CV onset time lag). However, we argue that the existing evidence is inconclusive, because previous cross-linguistic research has used small-scale data sets (one to seven speakers), and we still lack a well-grounded consensus on how gestural onsets are to be measured. This study uses Electromagnetic Articulography (EMA) to investigate word-initial CV coordination in a lexical pitch-accent language (Swedish) with a binary tonal word accent distinction: a tonal fall and a tonal rise, respectively. A selection of 13 spatial, temporal or coordinative measures of bilabial and tongue body data from 19 speakers, and acoustic f_o data, were examined to study the CV sequence /ma/. Mixed effects regression models revealed a longer tongue body movement in the rising tone context and small but significant differences in tongue body height, in the closing and the opening of the lips, as well as in the CV onset time lag between the two tonal contexts. We argue that these effects are biomechanical in nature, due to the physiological connections between the tongue, the jaw, and the larynx. In addition, our results suggest either synchronized CV onsets or a CV onset time lag (as in tone languages), depending on the timing landmarks used. In order to evaluate such results as evidence for or against the integration of tone in CV coarticulation, we argue that future research needs to compare data from a variety of languages using a considerable number of speakers. The present study provides new reference values for such comparisons.

Features of low functional load in mono- and bilinguals' lexical access: evidence from Swedish tonal accent

Swedish makes use of tonal accents (Accents 1 and 2) to contrast words, but the functional load is very low, with some regional dialects not even exhibiting the contrast. In particular given the low number of minimal pairs, the question is whether tonal word accent is used in lexical access. Here we present two cross-modal fragment semantic priming studies in order to address this question. Both experiments use first syllable fragments in order to prime semantically related targets. Experiment 1 utilises words whose first syllable occurs with both accent patterns, creating a situation in which there is lexical competition between words that differ solely in terms of accent. Experiment 2 removes this competition by using words that have no such accent competitors. Our results show that native speakers of Swedish use tonal word accent in lexical access: Accent mispronunciations failed to prime semantically related targets, regardless of whether primes had accent competitors or not. Results for a group of early bilingual speakers (who grew up with one Swedish-speaking parent and one other non-tonal language) showed no differences in processing compared to the monolinguals. This indicates that the extraction of accent features during acquisition and their use in lexical access is robust, even in a scenario where multiple input languages lead to tonal word accent being a useful feature for only some of the lexical items that are being acquired. There is no doubt that the accent system is well entrenched into the bilinguals' phonological system.

Decreased effective connectivity between insula and anterior cingulate cortex during a working memory task after prolonged sleep deprivation

Total sleep deprivation (TSD) causes a decline in almost all cognitive domains, especially working memory. However, we do not have a clear understanding of the degree working memory is impaired under prolonged TSD, nor do we know the underlying neurophysiological mechanism. In this study, we recorded EEG data from 64 subjects while they performed a working memory task during resting wakefulness, after 24 h TSD, and after 30 h TSD. ANOVA was used to verify performance differences between 24 h and 30 h TSD in working memory tasks: (1) reaction time and accuracy hit rates, (2) P200, N200, and P300 amplitude and latency in measurements of event-related potential, as well as (3) effective connectivity strength between brain areas associated with working memory. Compared to 24 h TSD, 30 h TSD significantly decreased accuracy hit rates and induced a larger N200 difference waveform. The effective connectivity analysis showed that 30 h TSD also decreased beta frequency in effective connection strength from the right insular lobe to the left anterior cingulate cortex (ACC). Effective connection from the left ventrolateral prefrontal cortex to the left dorsolateral prefrontal cortex increased in the match condition of the 2-back task. In conclusion, 30 h TSD had a greater negative impact on working memory than 24 h TSD. This impairment of working memory is associated with decreased strength in the effective connection from the right insula to the left ACC.

Cortical thickness and surface area of left anterior temporal areas affects processing of phonological cues to morphosyntax

Lack of methods to experimentally assess the perceptual processing of sound features and allow one to measure differences in phonological proficiency has been a limitation for speech processing studies in native speakers. Tonal features associated with Swedish word-stems, word accents, which cue grammatical suffixes, constitute, however, such sound features that can be exploited to generate measures of reliance on morphosyntactically relevant phonological information during word processing. Specifically, there is a natural variance between native speakers in response time (RT) difference between phonologically valid and invalid word accent-suffix combinations that can be used to quantify perceptual phonological proficiency. This study uses ultra-high field magnetic resonance imaging (MRI) to investigate word accents as phonological cues to morphosyntactic meaning. The study adds to the understanding of the neural basis for both morphosyntactically relevant phonological cues by reporting correlations between differences in listeners' RT for validly and invalidly cued suffixes and cortical thickness in left anterior and middle temporal gyrus, and the left anterior superior temporal sulcus as well as cortical surface area in the left middle and inferior temporal gyri. The cortical areas studied are known constituents of the ventral speech processing stream, necessary for word and phrase recognition.

Cortical thickness of Broca's area and right homologue is related to grammar learning aptitude and pitch discrimination proficiency

Aptitude for and proficiency in acquiring new languages varies in the human population but their neural bases are largely unknown. We investigated the influence of cortical thickness on language learning predictors measured by the LLAMA tests and a pitch-change discrimination test. The LLAMA tests are first language-independent assessments of language learning aptitude for vocabulary, phonetic working memory, sound-symbol correspondence (not used in this study), and grammatical inferencing. Pitch perception proficiency is known to predict aptitude for learning new phonology. Results show a correlation between scores in a grammatical meaning-inferencing aptitude test and cortical thickness of Broca's area (r(30) = 0.65, p = 0.0202) and other frontal areas (r(30) = 0.66, p = 0.0137). Further, a correlation was found between proficiency in discriminating pitch-change direction and cortical thickness of the right Broca homologue (r(30) = 0.57, p = 0.0006). However, no correlations were found for aptitude for vocabulary learning or phonetic working memory. Results contribute to locating cortical regions important for language-learning aptitude.

Rapid syntactic pre-activation in Broca's area: Concurrent electrophysiological and haemodynamic recordings

Listeners are constantly trying to predict what the speaker will say next. We concurrently measured the electrophysiological and haemodynamic correlates of syntactic pre-activation, investigating when and where the brain processes speech melody cues to upcoming word order structure. Pre-activation of syntactic structure was reflected in a left-lateralised pre-activation negativity (PrAN), which was subserved by Broca's area in the left inferior frontal gyrus, as well as the contiguous left anterior insula.

Tone-grammar association within words: Concurrent ERP and fMRI show rapid neural pre-activation and involvement of left inferior frontal gyrus in pseudoword processing

Using a concurrent ERP/fMRI paradigm, we investigated how listeners take advantage of morphologically relevant tonal information at the beginning of words to predict and pre-activate likely word endings. More predictive, low tone word stems gave rise to a 'pre-activation negativity' (PrAN) in the ERPs, a brain potential which has previously been found to increase along with the degree of predictive certainty as regards how a word is going to end. It is suggested that more predictive, low tone stems lead to rapid access to word endings with processing subserved by the left primary auditory cortex as well as the supramarginal gyrus, while high tone stems - which are less predictive - decrease predictive certainty, leading to increased competition between activated word endings, which needs to be resolved by the left inferior frontal gyrus.

Pre-Activation Negativity (PrAN) in Brain Potentials to Unfolding Words

We describe an event-related potential (ERP) effect termed the “pre-activation negativity” (PrAN), which is proposed to index the degree of pre-activation of upcoming word-internal morphemes in speech processing. Using lexical competition measures based on word-initial speech fragments (WIFs), as well as statistical analyses of ERP data from three experiments, it is shown that the PrAN is sensitive to lexical competition and that it reflects the degree of predictive certainty: the negativity is larger when there are fewer upcoming lexical competitors.