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1.
J Speech Lang Hear Res ; 66(5): 1694-1717, 2023 05 09.
Article in English | MEDLINE | ID: mdl-37093923

ABSTRACT

PURPOSE: The clinical use of event-related potentials in patients with language disorders is increasingly acknowledged. For this purpose, normative data should be available. Within this context, healthy aging and gender effects on the electrophysiological correlates of semantic sentence comprehension were investigated. METHOD: One hundred and ten healthy subjects (55 men and 55 women), divided among three age groups (young, middle aged, and elderly), performed a semantic sentence congruity task in the visual modality during electroencephalographic recording. RESULTS: The early visual complex was affected by increasing age as shown by smaller P2 amplitudes in the elderly compared to the young. Moreover, the N400 effect in the elderly was smaller than in the young and was delayed compared to latency measures in both middle-aged and young subjects. The topography of age-related amplitude changes of the N400 effect appeared to be gender specific. The late positive complex effect was increased at frontal electrode sites from middle age on, but this was not statistically significant. No gender effects were detected regarding the early P1, N1, and P2, or the late positive complex effect. CONCLUSION: Especially aging effects were found during semantic sentence comprehension, and this from the level of perceptual processing on. Normative data are now available for clinical use.


Subject(s)
Healthy Aging , Semantics , Middle Aged , Aged , Humans , Female , Male , Electroencephalography , Evoked Potentials/physiology , Comprehension/physiology
2.
Read Writ ; 36(5): 1283-1318, 2023.
Article in English | MEDLINE | ID: mdl-36032417

ABSTRACT

Individual differences in reading performance between children appear from the onset of literacy acquisition. One possible explanation for this variability is the influence of inhibition in reading ability, a topic that has received very little research attention. Nevertheless, children often make guessing errors characterized by replacing a word with an orthographic neighbor, possibly linked to failing inhibition. The present study aims to evaluate the role of inhibition during word and sentence reading and compare its effects in spoken and motor tasks. Participants comprised 25 children in Grades 2 and 3 (Mage = 8; 2). The children performed five inhibition tasks in reading (words, sentences), spoken (words, sentences) and motor modalities. Within the two reading tasks, inhibition demands were assessed using pairs of orthographic neighbors for which the frequency was manipulated. Accuracy, types of errors, latency, and response times were measured. GLMM analyses demonstrated that children were sensitive to the inhibitory demands of both spoken tasks and of the sentence reading task regarding accuracy, latency, and response times. Indeed, children made more mistakes and were slower when inhibitory demands were augmented. They also made more guessing errors in the word reading task. No such inhibitory effect was found in the motor task. Moreover, correlational analyses revealed that children who showed better inhibitory skills were able to read words and texts more accurately. These findings suggest that children need to utilize inhibitory resources when processing words or sentences and that these inhibitory skills are involved in overall reading ability.

3.
Front Neurosci ; 16: 947390, 2022.
Article in English | MEDLINE | ID: mdl-36278014

ABSTRACT

Aim: Examination of central compensatory mechanisms following peripheral vocal nerve injury and recovery is essential to build knowledge about plasticity of the neural network underlying phonation. The objective of this prospective multiple-cases longitudinal study is to describe brain activity in response to unilateral vocal fold paralysis (UVFP) management and to follow central nervous system adaptation over time in three patients with different nervous and vocal recovery profiles. Materials and methods: Participants were enrolled within 3 months of the onset of UVFP. Within 1 year of the injury, the first patient did not recover voice or vocal fold mobility despite voice therapy, the second patient recovered voice and mobility in absence of treatment and the third patient recovered voice and vocal fold mobility following an injection augmentation with hyaluronic acid in the paralyzed vocal fold. These different evolutions allowed comparison of individual outcomes according to nervous and vocal recovery. All three patients underwent functional magnetic resonance imaging (fMRI task and resting-state) scans at three (patient 1) or four (patients 2 and 3) time points. The fMRI task included three conditions: a condition of phonation and audition of the sustained [a:] vowel for 3 s, an audition condition of this vowel and a resting condition. Acoustic and aerodynamic measures as well as laryngostroboscopic images and laryngeal electromyographic data were collected. Results and conclusion: This study highlighted for the first time two key findings. First, hyperactivation during the fMRI phonation task was observed at the first time point following the onset of UVFP and this hyperactivation was related to an increase in resting-state connectivity between previoulsy described phonatory regions of interest. Second, for the patient who received an augmentation injection in the paralyzed vocal fold, we subsequently observed a bilateral activation of the voice-related nuclei in the brainstem. This new observation, along with the fact that for this patient the resting-state connectivity between the voice motor/sensory brainstem nuclei and other brain regions of interest correlated with an aerodynamic measure of voice, support the idea that there is a need to investigate whether the neural recovery process can be enhanced by promoting the restoration of proprioceptive feedback.

4.
J Voice ; 2022 Mar 16.
Article in English | MEDLINE | ID: mdl-35305893

ABSTRACT

OBJECTIVE: This review of the methodology and results of studies involving a sustained vowel phonation task during functional Magnetic Resonance Imaging (fMRI) aims to contribute to the identification of brain regions involved in phonation for healthy subjects. DATA SOURCES: This review was performed using the PubMed electronic database. REVIEW METHODS: A review was conducted, according to PRISMA guidelines, between September and November 2020, using the following search term pairs: "fMRI and Phonation" and "fMRI and Voice." Activation likelihood estimation analysis was performed. A qualitative analysis was also performed to specify the frequency of activation of each region, as well as the various activation clusters within a single region. RESULTS: Seven studies were included and analyzed. Five of the seven studies were selected for the activation likelihood estimation meta-analysis which revealed significant convergent activation for only one cluster located in the left precentral gyrus (BA4). A qualitative review provides an overview of brain activation. Primary motor and premotor areas were the only activated areas in all studies included. Other regions previously considered to be implicated in phonation were often activated in sustained vowel phonation tasks. Additionally, areas generally associated with articulation or language also showed activation. CONCLUSION: Methodological recommendations are suggested to isolate the phonatory component and reduce variability between future studies. Based on the qualitative analysis, this review does not support a distinction between regions more related to phonation and regions more related to articulation. Further research is required seeking to isolate the vocal component and to improve insight into human brain network involved in phonation.

5.
Proc Natl Acad Sci U S A ; 119(2)2022 01 11.
Article in English | MEDLINE | ID: mdl-34983868

ABSTRACT

Human learning is supported by multiple neural mechanisms that maturate at different rates and interact in mostly cooperative but also sometimes competitive ways. We tested the hypothesis that mature cognitive mechanisms constrain implicit statistical learning mechanisms that contribute to early language acquisition. Specifically, we tested the prediction that depleting cognitive control mechanisms in adults enhances their implicit, auditory word-segmentation abilities. Young adults were exposed to continuous streams of syllables that repeated into hidden novel words while watching a silent film. Afterward, learning was measured in a forced-choice test that contrasted hidden words with nonwords. The participants also had to indicate whether they explicitly recalled the word or not in order to dissociate explicit versus implicit knowledge. We additionally measured electroencephalography during exposure to measure neural entrainment to the repeating words. Engagement of the cognitive mechanisms was manipulated by using two methods. In experiment 1 (n = 36), inhibitory theta-burst stimulation (TBS) was applied to the left dorsolateral prefrontal cortex or to a control region. In experiment 2 (n = 60), participants performed a dual working-memory task that induced high or low levels of cognitive fatigue. In both experiments, cognitive depletion enhanced word recognition, especially when participants reported low confidence in remembering the words (i.e., when their knowledge was implicit). TBS additionally modulated neural entrainment to the words and syllables. These findings suggest that cognitive depletion improves the acquisition of linguistic knowledge in adults by unlocking implicit statistical learning mechanisms and support the hypothesis that adult language learning is antagonized by higher cognitive mechanisms.


Subject(s)
Cognition/physiology , Learning/physiology , Prefrontal Cortex/physiology , Adolescent , Adult , Electroencephalography , Female , Humans , Language , Language Development , Linguistics , Male , Memory, Short-Term/physiology , Mental Recall , Prefrontal Cortex/growth & development , Transcranial Magnetic Stimulation , Young Adult
7.
J Fluency Disord ; 69: 105850, 2021 09.
Article in English | MEDLINE | ID: mdl-33965883

ABSTRACT

PURPOSE: The current study examines how speech disfluencies manifest themselves in the two languages of bilingual persons who stutter, starting from the hypothesis that stuttering is associated with an attentional deficit at the level of speech production. METHODS: Twenty-eight bilingual people who stutter performed a spontaneous and a controlled speech production task, once in their dominant and once in their non-dominant language. The controlled production task (i.e. a network description task) was carried out once under a full-attention condition and once under a divided-attention condition where a non-linguistic, pitch discrimination task was performed simultaneously. RESULTS: In both the spontaneous and the controlled speech task, bilingual persons who stutter produced more (typical and stuttering-like) disfluencies in their L2 than in their L1. Furthermore, whereas the typical disfluencies increased when attention was directed away from speech production, stuttering-like disfluencies decreased. This effect was however restricted to L2. In addition, L2 proficiency was generally found to be a predicting factor, with higher proficiency leading to fewer disfluencies. CONCLUSIONS: These results suggest that speaking in a non-dominant language increases both typical and stuttering-like disfluencies in bilingual persons who stutter, but also that these two types of dysfluencies differ regarding their attentional origins. Our findings offer further support for attentional accounts of stuttering and have both theoretical and clinical implications.


Subject(s)
Stuttering , Attention , Humans , Language , Mediation Analysis , Speech , Speech Production Measurement
8.
J Exp Psychol Gen ; 150(12): 2423-2434, 2021 Dec.
Article in English | MEDLINE | ID: mdl-33856850

ABSTRACT

It is still an unresolved question why adults do not learn languages as effortlessly as children do. We tested the hypothesis that the higher cognitive control abilities in adults interfere with implicit learning mechanisms relevant for language acquisition. Across 2 days, Dutch-speaking adults were asked to rapidly recite novel syllable strings in which, unannounced to the participants, the allowed position of a phoneme depended on another adjacent phoneme. Their cognitive control system was either depleted or not depleted prior to learning, after performing an individually tailored dual working-memory task under high or low cognitive load. A third group did not perform any cognitive task prior to training. Speech error analyses revealed stronger (and faster) learning of the novel phoneme combination constraints in the cognitively depleted group compared with the other two groups. This indicates that late-developing cognitive control abilities, and in particular attentional control, constitute an important antagonist of implicit learning behavior relevant for language acquisition. These findings offer novel insights into developmental changes in implicit learning mechanisms and how to alter them temporarily in order to improve language skills in adults. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Subject(s)
Language , Speech , Adult , Child , Cognition , Humans , Language Development , Learning
9.
BMC Public Health ; 21(1): 622, 2021 03 30.
Article in English | MEDLINE | ID: mdl-33785029

ABSTRACT

BACKGROUND: The spread of COVID-19 has affected people's daily lives, and the lockdown may have led to a disruption of daily activities and a decrease of people's mental health. AIM: To identify correlates of adults' mental health during the COVID-19 lockdown in Belgium and to assess the role of meaningful activities in particular. METHODS: A cross-sectional web survey for assessing mental health (General Health Questionnaire), resilience (Connor-Davidson Resilience Scale), meaning in activities (Engagement in Meaningful Activities Survey), and demographics was conducted during the first Belgian lockdown between April 24 and May 4, 2020. The lockdown consisted of closing schools, non-essential shops, and recreational settings, employees worked from home or were technically unemployed, and it was forbidden to undertake social activities. Every adult who had access to the internet and lived in Belgium could participate in the survey; respondents were recruited online through social media and e-mails. Hierarchical linear regression was used to identify key correlates. RESULTS: Participants (N = 1781) reported low mental health (M = 14.85/36). In total, 42.4% of the variance in mental health could be explained by variables such as gender, having children, living space, marital status, health condition, and resilience (ß = -.33). Loss of meaningful activities was strongly related to mental health (ß = -.36) and explained 9% incremental variance (R2 change = .092, p < .001) above control variables. CONCLUSIONS: The extent of performing meaningful activities during the COVID-19 lockdown in Belgium was positively related to adults' mental health. Insights from this study can be taken into account during future lockdown measures in case of pandemics.


Subject(s)
Activities of Daily Living , COVID-19/psychology , Communicable Disease Control , Mental Health , Adult , Belgium/epidemiology , Cross-Sectional Studies , Female , Humans , Male , Pandemics
10.
Cognition ; 206: 104479, 2021 01.
Article in English | MEDLINE | ID: mdl-33157381

ABSTRACT

Compared to most human language abilities, the cognitive mechanisms underlying spelling have not been as intensively investigated as reading and therefore remain to this day less well understood. The current study aims to address this shortcoming by investigating the contribution of serial order short-term memory (STM) and long-term learning (LTL) abilities to emerging spelling skills. Indeed, although there are several reasons to assume associations between serial order memory and spelling abilities, this relationship has hardly been investigated empirically. In this study, we hypothesized that serial order STM plays an important role in spelling novel words, for which children are supposed to rely on a sequential nonlexical spelling procedure. Serial order LTL was hypothesized to be involved in the creation of more stable orthographic representations allowing children to spell (regular and irregular) words by using a lexical spelling strategy based on the direct access to orthographic representations stored in long-term memory. To assess these hypotheses, we conducted a longitudinal study in which we tested a sample of 116 French-speaking children at first grade and two years later at third grade of primary school. At first grade, we administered tasks that were specifically designed to maximize STM and LTL abilities for serial order information. At third grade, we assessed spelling abilities using irregular word, regular word, and pseudoword writing-to-dictation tasks. Bayesian regression analyses showed that pseudoword, but also irregular word spelling was best predicted by serial order STM, while regular word spelling was similarly predicted by both serial order STM and LTL.


Subject(s)
Language , Memory, Short-Term , Bayes Theorem , Child , Humans , Longitudinal Studies , Phonetics , Reading , Schools
11.
Dev Psychol ; 56(9): 1671-1683, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32614211

ABSTRACT

There is increasing evidence for an association between both serial order short-term memory (STM) and the long-term learning (LTL) of serial order information and reading abilities. In this developmental study, we examined the hypothesis that STM for serial order supports online grapheme-to-phoneme conversion processes during the initial stages of reading acquisition, whereas the LTL of serial order serves reading abilities at later stages, when reading starts to rely on more stable, long-term orthographic representations. We followed a sample of 116 French-speaking children from first (Time 1 [T1]) grade of primary school through second (Time 2 [T2]) and third (Time 3 [T3]) grade. Their serial order STM and LTL abilities as well as their reading abilities were assessed. Overall, we observed that early reading abilities were only predicted by serial order STM performance, while more advanced reading abilities were predicted by both serial order STM and LTL performance. These results point toward a predictive role of serial order memory performance in reading acquisition and suggest that serial order STM and LTL support reading at different stages of acquisition. We further discuss our findings in the light of advancing knowledge about the relationship between memory and reading. (PsycInfo Database Record (c) 2020 APA, all rights reserved).


Subject(s)
Memory, Short-Term , Reading , Humans , Learning , Longitudinal Studies , Serial Learning
12.
Hum Brain Mapp ; 41(14): 3956-3969, 2020 10 01.
Article in English | MEDLINE | ID: mdl-32573904

ABSTRACT

Hebb repetition learning is a fundamental learning mechanism for sequential knowledge, such as language. However, still little is known about its development. This fMRI study examined the developmental neural substrates of Hebb repetition learning and its relation with reading abilities in a group of 49 children aged from 6 to 12 years. In the scanner, the children carried out an immediate serial recall task for syllable sequences of which some sequences were repeated several times over the course of the session (Hebb repetition sequences). The rate of Hebb repetition learning was associated with modulation of activity in the medial temporal lobe. Importantly, for the age range studied here, learning-related medial temporal lobe modulation was independent of the age of the children. Furthermore, we observed an association between regular and irregular word reading abilities and the neural substrates of Hebb repetition learning. This study suggests that the functional neural substrates of Hebb repetition learning do not undergo further maturational changes in school age children, possibly because they are sustained by implicit sequential learning mechanisms which are considered to be fully developed by that age. Importantly, the neural substrates of Hebb learning remain significant determinants of children's learning abilities, such as reading.


Subject(s)
Aptitude/physiology , Brain Mapping , Child Development/physiology , Memory, Short-Term/physiology , Reading , Serial Learning/physiology , Speech Perception/physiology , Temporal Lobe/physiology , Verbal Learning/physiology , Child , Female , Humans , Magnetic Resonance Imaging , Male
13.
Front Psychol ; 11: 553970, 2020.
Article in English | MEDLINE | ID: mdl-33479564

ABSTRACT

Language-related potentials are increasingly used to objectify (mal)adaptive neuroplasticity in stroke-related aphasia recovery. Using preattentive [mismatch negativity (MMN)] and attentive (P300) phonologically related paradigms, neuroplasticity in sensory memory and cognitive functioning underlying phonological processing can be investigated. In aphasic patients, MMN amplitudes are generally reduced for speech sounds with a topographic source distribution in the right hemisphere. For P300 amplitudes and latencies, both normal and abnormal results have been reported. The current study investigates the preattentive and attentive phonological discrimination ability in 17 aphasic patients (6 monolinguals and 11 bilinguals, aged 41-71 years) at two timepoints during aphasia recovery. Between the two timepoints, a significant improvement of behavioral language performance in both languages is observed in all patients with the MMN latency at timepoint 1 as a predictive factor for aphasia recovery. In contrast to monolinguals, bilingual aphasic patients have a higher probability to improve their processing speed during rehabilitation, resulting in a shortening of the MMN latency over time, which sometimes progresses toward the normative values.

14.
Cognition ; 185: 144-150, 2019 04.
Article in English | MEDLINE | ID: mdl-30710840

ABSTRACT

It is widely accepted that specific memory processes, such as serial-order memory, are involved in written language development and predictive of reading and spelling abilities. The reverse question, namely whether orthographic abilities also affect serial-order memory, has hardly been investigated. In the current study, we compared 20 illiterate people with a group of 20 literate matched controls on a verbal and a visuospatial version of the Hebb paradigm, measuring both short- and long-term serial-order memory abilities. We observed better short-term serial-recall performance for the literate compared with the illiterate people. This effect was stronger in the verbal than in the visuospatial modality, suggesting that the improved capacity of the literate group is a consequence of learning orthographic skills. The long-term consolidation of ordered information was comparable across groups, for both stimulus modalities. The implications of these findings for current views regarding the bi-directional interactions between memory and written language development are discussed.


Subject(s)
Literacy , Memory, Short-Term/physiology , Mental Recall/physiology , Pattern Recognition, Visual/physiology , Psycholinguistics , Reading , Serial Learning/physiology , Space Perception/physiology , Speech Perception/physiology , Adolescent , Adult , Female , Humans , Male , Memory Consolidation/physiology , Young Adult
15.
Cogn Emot ; 33(6): 1302-1309, 2019 09.
Article in English | MEDLINE | ID: mdl-30646832

ABSTRACT

Accumulating evidence suggests that emotional information is often recognised faster than neutral information. Several studies examined the effects of valence and arousal on word recognition, but yielded partially diverging results. Here, we used two alternative versions of a constructive recognition paradigm in which a target word is hidden by a visual mask that gradually disappears, to investigate whether the emotional properties of words influence their speed of recognition. Participants were instructed either to classify the incrementally appearing word as emotional or non-emotional (semantic categorisation task) or to decide whether the appearing letter string is an existing word or not (lexical decision task). Results from both tasks revealed faster recognition times for high- compared to low-arousing words, and for positive compared to negative or neutral words. These findings indicate a recognition advantage for emotionally positive and highly arousing stimuli that persists even when visual word recognition is hampered and participants are encouraged to make more active, semantic inferences to generate the meaning of the emerging word.


Subject(s)
Arousal/physiology , Decision Making/physiology , Recognition, Psychology/physiology , Semantics , Adult , Emotions , Female , Humans , Male , Time Factors , Young Adult
16.
Hum Brain Mapp ; 40(5): 1541-1553, 2019 04 01.
Article in English | MEDLINE | ID: mdl-30430689

ABSTRACT

Behavioral and developmental studies have made a critical distinction between item and serial order processing components of verbal working memory (WM). This functional magnetic resonance imaging (fMRI) study determined the extent to which item and serial order WM components are characterized by specialized neural networks already in young children or whether this specialization emerges at a later developmental stage. Total of 59 children aged 7-12 years performed item and serial order short-term probe recognition tasks in an fMRI experiment. While a left frontoparietal network was recruited in both item and serial order WM conditions, the right intraparietal sulcus was selectively involved in the serial order WM condition. This neural segregation was modulated by age, with both networks becoming increasingly separated in older children. Our results indicate a progressive specialization of networks involved in item and order WM processes during cognitive development.


Subject(s)
Brain/growth & development , Brain/physiology , Memory, Short-Term/physiology , Aging/physiology , Brain/diagnostic imaging , Brain Mapping , Child , Child Development/physiology , Female , Frontal Lobe/diagnostic imaging , Frontal Lobe/growth & development , Frontal Lobe/physiology , Humans , Magnetic Resonance Imaging , Male , Nerve Net/diagnostic imaging , Nerve Net/growth & development , Nerve Net/physiology , Parietal Lobe/diagnostic imaging , Parietal Lobe/growth & development , Parietal Lobe/physiology , Recognition, Psychology/physiology , Verbal Learning
17.
Front Psychol ; 9: 1998, 2018.
Article in English | MEDLINE | ID: mdl-30405488

ABSTRACT

There is currently a lively debate in the literature whether bilingualism leads to enhanced cognitive control or not. Recent evidence suggests that knowledge of more than one language does not always suffice for the manifestation of a bilingual cognitive control advantage. As a result, ongoing research has focused on modalities of bilingual language use that may interact with the bilingual advantage. In this study, we explored the cognitive control performance of simultaneous interpreters. These highly proficient bilinguals comprehend information in one language while producing in the other language, which is a complex skill requiring high levels of language control. In a first experiment, we compared professional interpreters to monolinguals. Data were collected on interference suppression (flanker task), prepotent response inhibition (Simon task), and short-term memory (digit span task). The results showed that the professional interpreters performed similarly to the monolinguals on all measures. In Experiment 2, we compared professional interpreters to monolinguals and second language teachers. Data were collected on interference suppression (advanced flanker task), prepotent response inhibition (advanced flanker task), attention (advanced flanker task), short-term memory (Hebb repetition paradigm), and updating (n-back task). We found converging evidence for our finding that experience in interpreting may not lead to superior interference suppression, prepotent response inhibition, and short-term memory. In fact, our results showed that the professional interpreters performed similarly to both the monolinguals and the second language teachers on all tested cognitive control measures. We did, however, find anecdotal evidence for a (small) advantage in short-term memory for interpreters relative to monolinguals when analyzing composite scores of both experiments together. Taken together, the results of the current study suggest that interpreter experience does not necessarily lead to general cognitive control advantages. However, there may be small interpreter advantages in short-term memory, suggesting that this might be an important cognitive control aspect of simultaneous interpreting. The results are discussed in the light of ongoing debates about bilingual cognitive control advantages.

18.
Int J Lang Commun Disord ; 53(3): 515-525, 2018 05.
Article in English | MEDLINE | ID: mdl-29314421

ABSTRACT

BACKGROUND: Until today, there is no satisfying explanation for why one language may recover worse than another in differential bilingual aphasia. One potential explanation that has been largely unexplored is that differential aphasia is the consequence of a loss of language control rather than a loss of linguistic representations. Language control is part of a general control mechanism that also manages non-linguistic cognitive control. If this system is impaired, patients with differential aphasia could still show bilingual language activation, but they may be unable to manage activation in non-target languages, so that performance in another language is hindered. AIMS: To investigate whether a loss of cognitive control, rather than the loss of word representations in a particular language, might underlie differential aphasia symptoms. METHODS & PROCEDURES: We compared the performance of seven bilinguals with differential and eight bilinguals with parallel aphasia with 19 control bilinguals in a lexical decision and a flanker task to assess bilingual language co-activation and non-linguistic control respectively. OUTCOMES & RESULTS: We found similar cognate effects in the three groups, indicating similar lexical processing across groups. Additionally, we found a larger non-linguistic control congruency effect only for the patients with differential aphasia. CONCLUSIONS & IMPLICATIONS: The present data indicate preserved language co-activation for patients with parallel as well as differential aphasia. Furthermore, the results suggest a general cognitive control dysfunction, specifically for differential aphasia. Taken together, the results of the current study provide further support for the hypothesis of impaired cognitive control abilities in patients with differential aphasia, which has both theoretical and practical implications.


Subject(s)
Aphasia/psychology , Cognition , Cognitive Dysfunction/psychology , Multilingualism , Adult , Aged , Aged, 80 and over , Belgium , Case-Control Studies , Female , Humans , Language , Language Tests , Linguistics , Male , Middle Aged , Young Adult
19.
Dev Sci ; 21(5): e12634, 2018 09.
Article in English | MEDLINE | ID: mdl-29250874

ABSTRACT

Whereas adults often rely on explicit memory, children appear to excel in implicit memory, which plays an important role in the acquisition of various cognitive skills, such as those involved in language. The current study aimed to test the assertion of an age-dependent shift in implicit versus explicit learning within a theoretical framework that explains the link between implicit sequence memory and word-form acquisition, using the Hebb repetition paradigm. We conducted a one-year, multiple-session longitudinal study in which we presented auditory sequences of syllables, co-presented with pictures of aliens, for immediate serial recall by a group of children (8-9 years) and by an adult group. The repetition of one Hebb sequence was explicitly announced, while the repetition of another Hebb sequence was unannounced and, therefore, implicit. Despite their overall inferior recall performance, the children showed better offline retention of the implicit Hebb sequence, compared with adults who showed a significant decrement across the delays. Adults had gained more explicit knowledge of the implicit sequence than children, but this could not explain the age-dependent decline in the delayed memory for it. There was no significant age-effect for delayed memory of the explicit Hebb sequence, with both age groups showing retention. Overall performance by adults was positively correlated with measures of post-learning awareness. Performance by children was positively correlated with vocabulary knowledge. We conclude that children outperform adults in the retention over time of implicitly learned phonological sequences that will gradually consolidate into novel word-forms. The findings are discussed in the light of maturational differences for implicit versus explicit memory systems that also play a role in language acquisition. A video abstract of this article can be viewed at: https://youtu.be/G5nOfJB72t4.


Subject(s)
Language Development , Memory, Short-Term/physiology , Mental Recall/physiology , Pattern Recognition, Physiological/physiology , Verbal Learning/physiology , Vocabulary , Adult , Awareness/physiology , Child , Female , Humans , Language , Longitudinal Studies , Male
20.
Sci Rep ; 7(1): 13966, 2017 10 25.
Article in English | MEDLINE | ID: mdl-29070879

ABSTRACT

Adults do not learn languages as easily as children do. It has been hypothesized that the late-developing prefrontal cortex that supports executive functions competes with procedural learning mechanisms that are important for language learning. To address this hypothesis, we tested whether a temporary neural disruption of the left Dorsolateral Prefrontal Cortex (DLPFC) can improve implicit, procedural learning of word-forms in adults. Young adults were presented with repeating audio-visual sequences of syllables for immediate serial recall in a Hebb repetition learning task that simulates word-form learning. Inhibitory theta-burst Transcranial Magnetic Stimulation was applied to the left DLPFC or to the control site before the Hebb task. The DLPFC-disrupted group showed enhanced learning of the novel phonological sequences relative to the control group. Moreover, learning was negatively correlated with executive functions that rely on the DLPFC in the control group, but not in the DLPFC-disrupted group. The results support the hypothesis that a mature prefrontal cortex competes with implicit learning of word-forms. The findings provide new insight into the competition between brain mechanisms that contribute to language learning in the adult brain.


Subject(s)
Brain/physiology , Language Development , Prefrontal Cortex/physiology , Verbal Learning/physiology , Adult , Case-Control Studies , Executive Function , Female , Humans , Male , Memory, Short-Term , Transcranial Magnetic Stimulation , Young Adult
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