Foreign speech sound discrimination and associative word learning lead to a fast reconfiguration of resting-state networks.

Learning new words in an unfamiliar language is a complex endeavor that requires the orchestration of multiple perceptual and cognitive functions. Although the neural mechanisms governing word learning are becoming better understood, little is known about the predictive value of resting-state (RS) metrics for foreign word discrimination and word learning attainment. In addition, it is still unknown which of the multistep processes involved in word learning have the potential to rapidly reconfigure RS networks. To address these research questions, we used electroencephalography (EEG), measured forty participants, and examined scalp-based power spectra, source-based spectral density maps and functional connectivity metrics before (RS1), in between (RS2) and after (RS3) a series of tasks which are known to facilitate the acquisition of new words in a foreign language, namely word discrimination, word-referent mapping and semantic generalization. Power spectra at the scalp level consistently revealed a reconfiguration of RS networks as a function of foreign word discrimination (RS1 vs. RS2) and word learning (RS1 vs. RS3) tasks in the delta, lower and upper alpha, and upper beta frequency ranges. Otherwise, functional reconfigurations at the source level were restricted to the theta (spectral density maps) and to the lower and upper alpha frequency bands (spectral density maps and functional connectivity). Notably, scalp RS changes related to the word discrimination tasks (difference between RS2 and RS1) correlated with word discrimination abilities (upper alpha band) and semantic generalization performance (theta and upper alpha bands), whereas functional changes related to the word learning tasks (difference between RS3 and RS1) correlated with word discrimination scores (lower alpha band). Taken together, these results highlight that foreign speech sound discrimination and word learning have the potential to rapidly reconfigure RS networks at multiple functional scales.

Evidence for Enhanced Long-term Memory in Professional Musicians and Its Contribution to Novel Word Learning.

Previous studies evidenced transfer effects from professional music training to novel word learning. However, it is unclear whether such an advantage is driven by cascading, bottom-up effects from better auditory perception to semantic processing or by top-down influences from cognitive functions on perception. Moreover, the long-term effects of novel word learning remain an open issue. To address these questions, we used a word learning design, with four different sets of novel words, and we neutralized the potential perceptive and associative learning advantages in musicians. Under such conditions, we did not observe any advantage in musicians on the day of learning (Day 1 [D1]), at neither a behavioral nor an electrophysiological level; this suggests that the previously reported advantages in musicians are likely to be related to bottom-up processes. Nevertheless, 1 month later (Day 30 [D30]) and for all types of novel words, the error increase from D1 to D30 was lower in musicians compared to nonmusicians. In addition, for the set of words that were perceptually difficult to discriminate, only musicians showed typical N400 effects over parietal sites on D30. These results demonstrate that music training improved long-term memory and that transfer effects from music training to word learning (i.e., semantic levels of speech processing) benefit from reinforced (long-term) memory functions. Finally, these findings highlight the positive impact of music training on the acquisition of foreign languages.

From Psychoacoustics to Brain Waves: A Longitudinal Approach to Novel Word Learning.

Musical expertise has been shown to positively influence high-level speech abilities such as novel word learning. This study addresses the question whether low-level enhanced perceptual skills causally drives successful novel word learning. We used a longitudinal approach with psychoacoustic procedures to train 2 groups of nonmusicians either on pitch discrimination or on intensity discrimination, using harmonic complex sounds. After short (approximately 3 hr) psychoacoustic training, discrimination thresholds were lower on the specific feature (pitch or intensity) that was trained. Moreover, compared to the intensity group, participants trained on pitch were faster to categorize words varying in pitch. Finally, although the N400 components in both the word learning phase and in the semantic task were larger in the pitch group than in the intensity group, no between-group differences were found at the behavioral level in the semantic task. Thus, these results provide mixed evidence that enhanced perception of relevant features through a few hours of acoustic training with harmonic sounds causally impacts the categorization of speech sounds as well as novel word learning. These results are discussed within the framework of near and far transfer effects from music training to speech processing.

Phonetic Skills and Verbal Memory Capacity Predict Phonetic-based Word Learning: An Event-related Potential Study.

The learning of new words is a challenge that accompanies human beings throughout the entire life span. Although the main electrophysiological markers of word learning have already been described, little is known about the performance-dependent neural machinery underlying this exceptional human faculty. Furthermore, it is currently unknown how word learning abilities are related to verbal memory capacity, auditory attention functions, phonetic discrimination skills, and musicality. Accordingly, we used EEG and examined 40 individuals, who were assigned to two groups (low [LPs] and high performers [HPs]) based on a median split of word learning performance, while they completed a phonetic-based word learning task. Furthermore, we collected behavioral data during an attentive listening and a phonetic discrimination task with the same stimuli to address relationships between auditory attention and phonetic discrimination skills, word learning performance, and musicality. The phonetic-based word learning task, which also included a nonlearning control condition, was sensitive enough to segregate learning-specific and unspecific N200/N400 manifestations along the anterior-posterior topographical axis. Notably, HPs exhibited enhanced verbal memory capacity and we also revealed a performance-dependent spatial N400 pattern, with maximal amplitudes at posterior electrodes in HPs and central maxima in LPs. Furthermore, phonetic-based word learning performance correlated with verbal memory capacity and phonetic discrimination skills, whereas the latter was related to musicality. This experimental approach clearly highlights the multifaceted dimensions of phonetic-based word learning and is helpful to disentangle learning-specific and unspecific ERPs.

Enhanced neural and behavioural processing of a nonnative phonemic contrast in professional musicians.

Based on growing evidence suggesting that professional music training facilitates foreign language perception and learning, we examined the impact of musical expertise on the categorisation of syllables including phonemes that did (/p/, /b/) or did not (/ph /) belong to the French repertoire by analysing both behaviour (error rates and reaction times) and Event-Related brain Potentials (N200 and P300 components). Professional musicians and nonmusicians categorised syllables either as /ba/ or /pa/ (voicing task), or as /pa/ or /ph a/ with /ph / being a nonnative phoneme for French speakers (aspiration task). In line with our hypotheses, results showed that musicians outperformed nonmusicians in the aspiration task but not in the voicing task. Moreover, the difference between the native (/p/) and the nonnative phoneme (/ph /), as reflected in N200 and P300 amplitudes, was larger in musicians than in nonmusicians in the aspiration task but not in the voicing task. These results show that behaviour and brain activity associated to nonnative phoneme perception are influenced by musical expertise and that these effects are task-dependent. The implications of these findings for current models of phoneme perception and for understanding the qualitative and quantitative differences found on the N200 and P300 components are discussed.

Increased functional connectivity in the ventral and dorsal streams during retrieval of novel words in professional musicians.

Current models of speech and language processing postulate the involvement of two parallel processing streams (the dual stream model): a ventral stream involved in mapping sensory and phonological representations onto lexical and conceptual representations and a dorsal stream contributing to sound-to-motor mapping, articulation, and to how verbal information is encoded and manipulated in memory. Based on previous evidence showing that music training has an influence on language processing, cognitive functions, and word learning, we examined EEG-based intracranial functional connectivity in the ventral and dorsal streams while musicians and nonmusicians learned the meaning of novel words through picture-word associations. In accordance with the dual stream model, word learning was generally associated with increased beta functional connectivity in the ventral stream compared to the dorsal stream. In addition, in the linguistically most demanding "semantic task," musicians outperformed nonmusicians, and this behavioral advantage was accompanied by increased left-hemispheric theta connectivity in both streams. Moreover, theta coherence in the left dorsal pathway was positively correlated with the number of years of music training. These results provide evidence for a complex interplay within a network of brain regions involved in semantic processing and verbal memory functions, and suggest that intensive music training can modify its functional architecture leading to advantages in novel word learning.

Professional Music Training and Novel Word Learning: From Faster Semantic Encoding to Longer-lasting Word Representations.

On the basis of previous results showing that music training positively influences different aspects of speech perception and cognition, the aim of this series of experiments was to test the hypothesis that adult professional musicians would learn the meaning of novel words through picture-word associations more efficiently than controls without music training (i.e., fewer errors and faster RTs). We also expected musicians to show faster changes in brain electrical activity than controls, in particular regarding the N400 component that develops with word learning. In line with these hypotheses, musicians outperformed controls in the most difficult semantic task. Moreover, although a frontally distributed N400 component developed in both groups of participants after only a few minutes of novel word learning, in musicians this frontal distribution rapidly shifted to parietal scalp sites, as typically found for the N400 elicited by known words. Finally, musicians showed evidence for better long-term memory for novel words 5 months after the main experimental session. Results are discussed in terms of cascading effects from enhanced perception to memory as well as in terms of multifaceted improvements of cognitive processing due to music training. To our knowledge, this is the first report showing that music training influences semantic aspects of language processing in adults. These results open new perspectives for education in showing that early music training can facilitate later foreign language learning. Moreover, the design used in the present experiment can help to specify the stages of word learning that are impaired in children and adults with word learning difficulties.

Twelve months of active musical training in 8- to 10-year-old children enhances the preattentive processing of syllabic duration and voice onset time.

Musical training has been shown to positively influence linguistic abilities. To follow the developmental dynamics of this transfer effect at the preattentive level, we conducted a longitudinal study over 2 school years with nonmusician children randomly assigned to music or to painting training. We recorded the mismatch negativity (MMN), a cortical correlate of preattentive mismatch detection, to syllables that differed in vowel frequency, vowel duration, and voice onset time (VOT), using a test-training-retest procedure and 3 times of testing: before training, after 6 months and after 12 months of training. While no between-group differences were found before training, enhanced preattentive processing of syllabic duration and VOT, as reflected by greater MMN amplitude, but not of frequency, was found after 12 months of training in the music group only. These results demonstrate neuroplasticity in the child brain and suggest that active musical training rather than innate predispositions for music yielded the improvements in musically trained children. These results also highlight the influence of musical training for duration perception in speech and for the development of phonological representations in normally developing children. They support the importance of music-based training programs for children's education and open new remediation strategies for children with language-based learning impairments.

Conceptual priming for realistic auditory scenes and for auditory words.

Two experiments were conducted using both behavioral and Event-Related brain Potentials methods to examine conceptual priming effects for realistic auditory scenes and for auditory words. Prime and target sounds were presented in four stimulus combinations: Sound-Sound, Word-Sound, Sound-Word and Word-Word. Within each combination, targets were conceptually related to the prime, unrelated or ambiguous. In Experiment 1, participants were asked to judge whether the primes and targets fit together (explicit task) and in Experiment 2 they had to decide whether the target was typical or ambiguous (implicit task). In both experiments and in the four stimulus combinations, reaction times and/or error rates were longer/higher and the N400 component was larger to ambiguous targets than to conceptually related targets, thereby pointing to a common conceptual system for processing auditory scenes and linguistic stimuli in both explicit and implicit tasks. However, fine-grained analyses also revealed some differences between experiments and conditions in scalp topography and duration of the priming effects possibly reflecting differences in the integration of perceptual and cognitive attributes of linguistic and nonlinguistic sounds. These results have clear implications for the building-up of virtual environments that need to convey meaning without words.

Music training for the development of speech segmentation.

The role of music training in fostering brain plasticity and developing high cognitive skills, notably linguistic abilities, is of great interest from both a scientific and a societal perspective. Here, we report results of a longitudinal study over 2 years using both behavioral and electrophysiological measures and a test-training-retest procedure to examine the influence of music training on speech segmentation in 8-year-old children. Children were pseudo-randomly assigned to either music or painting training and were tested on their ability to extract meaningless words from a continuous flow of nonsense syllables. While no between-group differences were found before training, both behavioral and electrophysiological measures showed improved speech segmentation skills across testing sessions for the music group only. These results show that music training directly causes facilitation in speech segmentation, thereby pointing to the importance of music for speech perception and more generally for children's language development. Finally these results have strong implications for promoting the development of music-based remediation strategies for children with language-based learning impairments.

More to explore in music reading as a cross-modal process: a comment on Lee and Lei (2012).

Lee and Lei (2012) used a pitch task and a duration task in different blocks of trials and measured event-related potentials in 12 musicians and 24 non-musicians as they read musical scores. The authors claimed to disentangle pitch and duration processing. From the perspectives of cognitive neuropsychology there is great interest in studying the processes involved in reading musical scores. However, we argue that the design used by Lee and Lei (2012) does not allow disentangling pitch and duration processing because both are expressed within the musical score. Moreover, we emphasize the importance of longitudinal studies over cross-sectional studies to pinpoint the specific influence of musical expertise on score reading.

Effects of Psychoacoustic Training on the Pre-Attentive Processing of Harmonic Sounds and Syllables.

PURPOSE: This article aimed at investigating the neural underpinnings of music-to-language transfer effects at the pre-attentive level of processing. METHOD: We conducted a longitudinal experiment with a test-training-retest procedure. Nonmusician adults were trained either on frequency (experimental group) or on intensity (control group) of harmonic tones using methods from psychophysics. Pre- and posttraining, we recorded brain electrical activity and we analyzed the mismatch negativity (MMN) and the P3a component both to harmonic complex sounds and to syllables varying in frequency. RESULTS: Frequency training influenced the pre-attentive perception of pitch for large harmonic deviant sounds but not for syllables. CONCLUSION: Results are discussed in terms of near and far transfer effects from psychoacoustic training to pre-attentive pitch processing and as possibly showing some limits to transfer effects.

The electrophysiological correlates of word pre-activation during associative word learning.

Human beings continuously make use of learned associations to generate predictions about future occurrences in the environment. Such memory-related predictive processes provide a scaffold for learning in that mental representations of foreseeable events can be adjusted or strengthened based on a specific outcome. Learning the meaning of novel words through picture-word associations constitutes a prime example of associative learning because pictures preceding words can trigger word prediction through the pre-activation of the related mnemonic representations. In the present electroencephalography (EEG) study, we used event-related potentials (ERPs) to compare neural indices of word pre-activation between a word learning condition with maximal prediction likelihood and a non-learning control condition with low prediction. Results revealed that prediction-related N400 amplitudes in response to pictures decreased over time at central electrodes as a function of word learning, whereas late positive component (LPC) amplitudes increased. Notably, N400 but not LPC changes were also predictive of word learning performance, suggesting that the N400 component constitutes a sensitive marker of word pre-activation during associative word learning.

Sleep pattern in the dromedary camel: a behavioral and polysomnography study.

STUDY OBJECTIVES: To investigate sleep patterns in the camel by combining behavioral and polysomnography (PSG) methods. METHODS: A noninvasive PSG study was conducted over four nights on four animals. Additionally, video recordings were used to monitor the sleep behaviors associated with different vigilance states. RESULTS: During the night, short periods of sporadic sleep-like behavior corresponding to a specific posture, sternal recumbency (SR) with the head lying down on the ground, were observed. The PSG results showed rapid shifts between five vigilance states, including wakefulness, drowsiness, rapid eye movement (REM) sleep, non-REM (NREM) sleep, and rumination. The camels typically slept only 1.7 hours per night, subdivided into 0.5 hours of REM sleep and 1.2 hours of NREM sleep. Camels spent most of the night being awake (2.3 hours), ruminating (2.4 hours), or drowsing (1.9 hours). Various combinations of transitions between the different vigilance states were observed, with a notable transition into REM sleep directly from drowsiness (9%) or wakefulness (4%). Behavioral postures were found to correlate with PSG vigilance states, thereby allowing a reliable prediction of the sleep stage based on SR and the head position (erected, motionless, or lying down on the ground). Notably, 100% of REM sleep occurred during the Head Lying Down-SR posture. CONCLUSIONS: The camel is a diurnal species with a polyphasic sleep pattern at night. The best correlation between PSG and ethogram data indicates that sleep duration can be predicted by the behavioral method, provided that drowsiness is considered a part of sleep.

Musicians and the metric structure of words.

The present study aimed to examine the influence of musical expertise on the metric and semantic aspects of speech processing. In two attentional conditions (metric and semantic tasks), musicians listened to short sentences ending in trisyllabic words that were semantically and/or metrically congruous or incongruous. Both ERPs and behavioral data were analyzed and the results were compared to previous nonmusicians' data. Regarding the processing of meter, results showed that musical expertise influenced the automatic detection of the syllable temporal structure (P200 effect), the integration of metric structure and its influence on word comprehension (N400 effect), as well as the reanalysis of metric violations (P600 and late positivities effects). By contrast, results showed that musical expertise did not influence the semantic level of processing. These results are discussed in terms of transfer of training effects from music to speech processing.

Influence of musical expertise on segmental and tonal processing in Mandarin Chinese.

A same-different task was used to test the hypothesis that musical expertise improves the discrimination of tonal and segmental (consonant, vowel) variations in a tone language, Mandarin Chinese. Two four-word sequences (prime and target) were presented to French musicians and nonmusicians unfamiliar with Mandarin, and event-related brain potentials were recorded. Musicians detected both tonal and segmental variations more accurately than nonmusicians. Moreover, tonal variations were associated with higher error rate than segmental variations and elicited an increased N2/N3 component that developed 100 msec earlier in musicians than in nonmusicians. Finally, musicians also showed enhanced P3b components to both tonal and segmental variations. These results clearly show that musical expertise influenced the perceptual processing as well as the categorization of linguistic contrasts in a foreign language. They show positive music-to-language transfer effects and open new perspectives for the learning of tone languages.

Enhanced passive and active processing of syllables in musician children.

The aim of this study was to examine the influence of musical expertise in 9-year-old children on passive (as reflected by MMN) and active (as reflected by discrimination accuracy) processing of speech sounds. Musician and nonmusician children were presented with a sequence of syllables that included standards and deviants in vowel frequency, vowel duration, and VOT. Both the passive and the active processing of duration and VOT deviants were enhanced in musician compared with nonmusician children. Moreover, although no effect was found on the passive processing of frequency, active frequency discrimination was enhanced in musician children. These findings are discussed in terms of common processing of acoustic features in music and speech and of positive transfer of training from music to the more abstract phonological representations of speech units (syllables).

Sound categorization and conceptual priming for nonlinguistic and linguistic sounds.

The aim of these experiments was to compare conceptual priming for linguistic and for a homogeneous class of nonlinguistic sounds, impact sounds, by using both behavioral (percentage errors and RTs) and electrophysiological measures (ERPs). Experiment 1 aimed at studying the neural basis of impact sound categorization by creating typical and ambiguous sounds from different material categories (wood, metal, and glass). Ambiguous sounds were associated with slower RTs and larger N280, smaller P350/P550 components, and larger negative slow wave than typical impact sounds. Thus, ambiguous sounds were more difficult to categorize than typical sounds. A category membership task was used in Experiment 2. Typical sounds were followed by sounds from the same or from a different category or by ambiguous sounds. Words were followed by words, pseudowords, or nonwords. Error rate was highest for ambiguous sounds and for pseudowords and both elicited larger N400-like components than same typical sounds and words. Moreover, both different typical sounds and nonwords elicited P300 components. These results are discussed in terms of similar conceptual priming effects for nonlinguistic and linguistic stimuli.

The evocative power of sounds: conceptual priming between words and nonverbal sounds.

Two experiments were conducted to examine the conceptual relation between words and nonmeaningful sounds. In order to reduce the role of linguistic mediation, sounds were recorded in such a way that it was highly unlikely to identify the source that produced them. Related and unrelated sound-word pairs were presented in Experiment 1 and the order of presentation was reversed in Experiment 2 (word-sound). Results showed that, in both experiments, participants were sensitive to the conceptual relation between the two items. They were able to correctly categorize items as related or unrelated with good accuracy. Moreover, a relatedness effect developed in the event-related brain potentials between 250 and 600 msec, although with a slightly different scalp topography for word and sound targets. Results are discussed in terms of similar conceptual processing networks and we propose a tentative model of the semiotics of sounds.

Similar cerebral networks in language, music and song perception.

Two fMRI experiments were conducted using song to investigate the domain specificity of linguistic and musical processing. In Experiment 1, participants listened to pairs of spoken words, "vocalise" (i.e., singing without words), and sung words while performing a same-different task. Results revealed bilateral involvement of middle and superior temporal gyri and inferior and middle frontal gyri while listening to spoken words, sung words and vocalise, although to different degrees. In Experiment 2, participants listened to pairs of sung words that were similar or different in terms of the linguistic and musical dimensions (2x2 factorial event-related design) while performing a same-different task. Results showed widespread interactions between the linguistic and musical dimensions of sung words mainly within the network of brain areas identified in Experiment 1. Consequently, the activity in these brain regions cannot be considered as specific to either language or music processing. Taken together, results of both experiments argue against domain specificity and provide additional evidence for a common cerebral network involved in both lexical/phonological and melodic processing.