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Confidence in our retrieved memories, that is, retrospective confidence, is a metamemory process we perform daily. There is an abundance of applied research focusing on the metamemory judgments and very diverse studies including a wide range of clinical populations. However, the neural correlates that support its functioning are not well defined impeding the implementation of noninvasive neuromodulatory clinical interventions. To address the neural basis of metamemory judgments, we ran a meta‐analysis, where we used the activation likelihood estimation method on the 19 eligible functional magnetic resonance imaging studies. The main analysis of retrospective confidence revealed concordant bilateral activation in the parahippocampal gyrus, left middle frontal gyrus, and right amygdala. We also run an analysis between the two extreme levels of confidence, namely, high and low. This additional analysis was exploratory, since the minimum amount of articles reporting these two levels was not reached. Activations for the exploratory high > low confidence subtraction analysis were the same as observed in the main analysis on retrospective confidence, whereas the exploratory low > high subtraction showed distinctive activations of the right precuneus. The involvement of the right precuneus emphasizes its role in the evaluation of low confidence memories, as suggested by previous studies. Overall, our study contributes to a better understanding of the specific brain structures involved in confidence evaluations. Better understanding of the neural basis of metamemory might eventually lead to designing more precise neuromodulatory interventions, significantly improving treatment of patients suffering from metamemory problems. [ABSTRACT FROM AUTHOR]

The aim of this review is to provide a selective overview of priming studies which have employed the event-related brain potential (ERP) technique in order to investigate bilingual language processing. The priming technique can reveal an implicit memory effect in which exposure to one stimulus influences the processing of another stimulus. Behavioral approaches, such as measuring reaction times, may not always be enough for providing a full view on the exact mechanisms and the time-course of language comprehension. Instead, ERPs have a time-resolution of a millisecond and hence they offer a precise temporal overview of the underlying neural processes involved in language processing. In our review, we summarize experimental research that has combined priming with ERP measurements, thus creating a valuable tool for examining the neurophysiological correlates of language processing in the bilingual brain. [ABSTRACT FROM AUTHOR]

How do late proficient bilinguals process morphosyntactic and lexical-semantic information in their non-native language (L2)? How is this information represented in the L2 mental lexicon? And what are the neural signatures of L2 morphosyntactic and lexical-semantic processing? We addressed these questions in one behavioral and two ERP priming experiments on inflected German adjectives testing a group of advanced late Russian learners of German in comparison to native speaker (L1) controls. While in the behavioral experiment, the L2 learners performed native-like, the ERP data revealed clear L1/L2 differences with respect to the temporal dynamics of grammatical processing. Specifically, our results show that L2 morphosyntactic processing yielded temporally and spatially extended brain responses relative to L1 processing, indicating that grammatical processing of inflected words in an L2 is more demanding and less automatic than in the L1. However, this group of advanced L2 learners showed native-like lexical-semantic processing. [ABSTRACT FROM AUTHOR]

Children’s obligatory auditory event-related potentials (ERPs) to speech and nonspeech sounds have been shown to associate with reading performance in children at risk or with dyslexia and their controls. However, very little is known of the cognitive processes these responses reflect. To investigate this question, we recorded ERPs to semisynthetic syllables and their acoustically matched nonspeech counterparts in 63 typically developed preschoolers, and assessed their verbal skills with an extensive set of neurocognitive tests. P1 and N2 amplitudes were larger for nonspeech than speech stimuli, whereas the opposite was true for N4. Furthermore, left-lateralized P1s were associated with better phonological and prereading skills, and larger P1s to nonspeech than speech stimuli with poorer verbal reasoning performance. Moreover, left-lateralized N2s, and equal-sized N4s to both speech and nonspeech stimuli were associated with slower naming. In contrast, children with equal-sized N2 amplitudes at left and right scalp locations, and larger N4s for speech than nonspeech stimuli, performed fastest. We discuss the possibility that children’s ERPs reflect not only neural encoding of sounds, but also sound quality processing, memory-trace construction, and lexical access. The results also corroborate previous findings that speech and nonspeech sounds are processed by at least partially distinct neural substrates. [ABSTRACT FROM AUTHOR]

Abstract: This study uses event-related brain potentials (ERPs) to investigate the temporal sequencing of structural (grammatical) and lexical (semantic) properties of complex words during language comprehension. Morphologically complex words do not only consist of stems and affixes (e.g., ‘feel’+‘-s’), but affixes also contain grammatical structure, viz. feature bundles specifying their morpho-syntactic functions (e.g., -s= [3rd person, singular, present tense]). We examined inflected adjectives of German, which consist of an unaltered stem plus a portmanteau affix encoding case, number and gender. The same group of 24 adult native speakers was tested in two cross-modal ERP priming experiments separately studying effects of lexical–semantic relatedness and related affixes. The results of these experiments revealed clearly distinct brain potentials. Prime-target overlap with respect to morpho-syntactic features was associated with a reduced positivity, whereas lexical-level priming led to a reduced negativity. The former was most pronounced between 200 and 300ms and the latter in a later time window, between 300 and 400ms. We interpret the reduced early positivity as reflecting ease of grammatical processing effort in case of primed (relative to unprimed) morpho-syntactic features and the reduced negativity as signaling facilitation in lexical retrieval for primed (compared to unprimed) words. Our ERP results indicate that grammatical information becomes available earlier than semantic information providing support for structure-first models of language processing. [Copyright &y& Elsevier]

This study determined to what extent morphological processing of spoken inflected and derived words is attention-independent. To answer these questions EEG and MEG responses were recorded from healthy participants while they were presented with spoken Finnish inflected, derived, and monomorphemic words. In the non-attended task, the participants were instructed to ignore the incoming auditory stimuli and concentrate on the silent cartoon. In the attended task, previously reported by Leminen et al. (2011), the participants were to judge the acceptability of each stimulus. Importantly, EEG and MEG responses were time-locked to the onset of critical information [suffix onset for the complex words and uniqueness point (UP) for the monomorphemic words]. Early after the critical point, word type did not interact with task: in both attended and non-attended tasks, the event-related potentials (ERPs) showed larger negativity to derived than inflected or monomorphemic words ∼100ms after the critical point. MEG source waveforms showed a similar pattern. Later than 100 ms after the critical point, there were no differences between word types in the non-attended task either in the ERP or source modeling data. However, in the attended task inflected words elicited larger responses than other words ∼200 ms after the critical point. The results suggest different brain representations for derived and inflected words. The early activation after the critical point was elicited both in the non-attended and attended tasks. As this stage of word recognition was not modulated by attention, it can be concluded to reflect an automatic mapping of incoming acoustic information onto stored representations. In contrast, the later differences between word types in the attended task were not observed in the non-attended task. This indicates that later compositional processes at the (morpho)syntactic-semantic level require focused attention. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses reports within the issue on topics related to neuroscience including the importance of morphological information in language processing.

While previous studies on language processing highlighted several ERP components in relation to specific stages of sound and speech processing, no study has yet combined them to obtain a comprehensive picture of language abilities in a single session. Here, we propose a novel task‐free paradigm aimed at assessing multiple levels of speech processing by combining various speech and nonspeech sounds in an adaptation of a multifeature passive oddball design. We recorded EEG in healthy adult participants, who were presented with these sounds in the absence of sound‐directed attention while being engaged in a primary visual task. This produced a range of responses indexing various levels of sound processing and language comprehension: (a) P1‐N1 complex, indexing obligatory auditory processing; (b) P3‐like dynamics associated with involuntary attention allocation for unusual sounds; (c) enhanced responses for native speech (as opposed to nonnative phonemes) from ∼50 ms from phoneme onset, indicating phonological processing; (d) amplitude advantage for familiar real words as opposed to meaningless pseudowords, indexing automatic lexical access; (e) topographic distribution differences in the cortical activation of action verbs versus concrete nouns, likely linked with the processing of lexical semantics. These multiple indices of speech‐sound processing were acquired in a single attention‐free setup that does not require any task or subject cooperation; subject to future research, the present protocol may potentially be developed into a useful tool for assessing the status of auditory and linguistic functions in uncooperative or unresponsive participants, including a range of clinical or developmental populations. [ABSTRACT FROM AUTHOR]

A unique feature of human communication system is our ability to rapidly acquire new words and build large vocabularies. However, its neurobiological foundations remain largely unknown. In an electrophysiological study optimally designed to probe this rapid formation of new word memory circuits, we employed acoustically controlled novel word-forms incorporating native and non-native speech sounds, while manipulating the subjects' attention on the input. We found a robust index of neurolexical memory-trace formation: a rapid enhancement of the brain's activation elicited by novel words during a short (~ 30 min) perceptual exposure, underpinned by fronto-temporal cortical networks, and, importantly, correlated with behavioural learning outcomes. Crucially, this neural memory trace build-up took place regardless of focused attention on the input or any pre-existing or learnt semantics. Furthermore, it was found only for stimuli with native-language phonology, but not for acoustically closely matching non-native words. These findings demonstrate a specialised cortical mechanism for rapid, automatic and phonology-dependent formation of neural word memory circuits. [ABSTRACT FROM AUTHOR]

Children learn new words and word forms with ease, often acquiring a new word after very few repetitions. Recent neurophysiological research on word form acquisition in adults indicates that novel words can be acquired within minutes of repetitive exposure to them, regardless of the individual's focused attention on the speech input. Although it is well-known that children surpass adults in language acquisition, the developmental aspects of such rapid and automatic neural acquisition mechanisms remain unexplored. To address this open question, we used magnetoencephalography (MEG) to scrutinise brain dynamics elicited by spoken words and word-like sounds in healthy monolingual (Danish) children throughout a 20-min repetitive passive exposure session. We found rapid neural dynamics manifested as an enhancement of early (~100 ms) brain activity over the short exposure session, with distinct spatiotemporal patterns for different novel sounds. For novel Danish word forms, signs of such enhancement were seen in the left temporal regions only, suggesting reliance on pre-existing language circuits for acquisition of novel word forms with native phonology. In contrast, exposure both to novel word forms with non-native phonology and to novel non-speech sounds led to activity enhancement in both left and right hemispheres, suggesting that more wide-spread cortical networks contribute to the build-up of memory traces for non-native and non-speech sounds. Similar studies in adults have previously reported more sluggish (~15–25 min, as opposed to 4 min in the present study) or non-existent neural dynamics for non-native sound acquisition, which might be indicative of a higher degree of plasticity in the children's brain. Overall, the results indicate a rapid and highly plastic mechanism for a dynamic build-up of memory traces for novel acoustic information in the children's brain that operates automatically and recruits bilateral temporal cortical circuits. [ABSTRACT FROM AUTHOR]

In real-life noisy situations, we can selectively attend to conversations in the presence of irrelevant voices, but neurocognitive mechanisms in such natural listening situations remain largely unexplored. Previous research has shown distributed activity in the mid superior temporal gyrus (STG) and sulcus (STS) while listening to speech and human voices, in the posterior STS and fusiform gyrus when combining auditory, visual and linguistic information, as well as in left-hemisphere temporal and frontal cortical areas during comprehension. In the present functional magnetic resonance imaging (fMRI) study, we investigated how selective attention modulates neural responses to naturalistic audiovisual dialogues. Our healthy adult participants ( N = 15) selectively attended to video-taped dialogues between a man and woman in the presence of irrelevant continuous speech in the background. We modulated the auditory quality of dialogues with noise vocoding and their visual quality by masking speech-related facial movements. Both increased auditory quality and increased visual quality were associated with bilateral activity enhancements in the STG/STS. In addition, decreased audiovisual stimulus quality elicited enhanced fronto-parietal activity, presumably reflecting increased attentional demands. Finally, attention to the dialogues, in relation to a control task where a fixation cross was attended and the dialogue ignored, yielded enhanced activity in the left planum polare, angular gyrus, the right temporal pole, as well as in the orbitofrontal/ventromedial prefrontal cortex and posterior cingulate gyrus. Our findings suggest that naturalistic conversations effectively engage participants and reveal brain networks related to social perception in addition to speech and semantic processing networks., (Copyright © 2020 Leminen, Verwoert, Moisala, Salmela, Wikman and Alho.)

This study determined to what extent morphological processing of spoken inflected and derived words is attention-independent. To answer these questions EEG and MEG responses were recorded from healthy participants while they were presented with spoken Finnish inflected, derived, and monomorphemic words. In the non-attended task, the participants were instructed to ignore the incoming auditory stimuli and concentrate on the silent cartoon. In the attended task, previously reported by Leminen et al. (2011), the participants were to judge the acceptability of each stimulus. Importantly, EEG and MEG responses were time-locked to the onset of critical information [suffix onset for the complex words and uniqueness point (UP) for the monomorphemic words]. Early after the critical point, word type did not interact with task: in both attended and non-attended tasks, the event-related potentials (ERPs) showed larger negativity to derived than inflected or monomorphemic words ~100 ms after the critical point. MEG source waveforms showed a similar pattern. Later than 100 ms after the critical point, there were no differences between word types in the non-attended task either in the ERP or source modeling data. However, in the attended task inflected words elicited larger responses than other words ~200 ms after the critical point. The results suggest different brain representations for derived and inflected words. The early activation after the critical point was elicited both in the non-attended and attended tasks. As this stage of word recognition was not modulated by attention, it can be concluded to reflect an automatic mapping of incoming acoustic information onto stored representations. In contrast, the later differences between word types in the attended task were not observed in the non-attended task. This indicates that later compositional processes at the (morpho)syntactic-semantic level require focused attention.

The spatiotemporal dynamics of the neural processing of spoken morphologically complex words are still an open issue. In the current study, we investigated the time course and neural sources of spoken inflected and derived words using simultaneously recorded electroencephalography (EEG) and magnetoencephalography (MEG) responses. Ten participants (native speakers) listened to inflected, derived, and monomorphemic Finnish words and judged their acceptability. EEG and MEG responses were time-locked to both the stimulus onset and the critical point (suffix onset for complex words, uniqueness point for monomorphemic words). The ERP results showed that inflected words elicited a larger left-lateralized negativity than derived and monomorphemic words approximately 200 ms after the critical point. Source modeling of MEG responses showed one bilateral source in the superior temporal area ∼100 ms after the critical point, with derived words eliciting stronger source amplitudes than inflected and monomorphemic words in the right hemisphere. Source modeling also showed two sources in the temporal cortex approximately 200 ms after the critical point. There, inflected words showed a more systematic pattern in source locations and elicited temporally distinct source activity in comparison to the derived word condition. The current results provide electrophysiological evidence for at least partially distinct cortical processing of spoken inflected and derived words. In general, the results support models of morphological processing stating that during the recognition of inflected words, the constituent morphemes are accessed separately. With regard to derived words, stem and suffix morphemes might be at least initially activated along with the whole word representation.