Phonetic training and non-native speech perception - New memory traces evolve in just three days as indexed by the mismatch negativity (MMN) and behavioural measures

Language-specific, automatically responding memory traces form the basis for speech sound perception and new neural representations can also evolve for non-native speech categories. The aim of this study was to find out how a three-day phonetic listen-and-repeat training affects speech perception, and whether it generates new memory traces. We used behavioural identification, goodness rating, discrimination, and reaction time tasks together with mismatch negativity (MMN) brain response registrations to determine the training effects on native Finnish speakers. We trained the subjects the voicing contrast in fricative sounds. Fricatives are not differentiated by voicing in Finnish, i.e., voiced fricatives do not belong to the Finnish phonological system. Therefore, they are extremely hard for Finns to learn. However, only after three days of training, the native Finnish subjects had learned to perceive the distinction. The results show striking changes in the MMN response; it was significantly larger on the second day after two training sessions. Also, the majority of the behavioural indicators showed improvement during training. Identification altered after four sessions of training and discrimination and reaction times improved throughout training. These results suggest remarkable language-learning effects both at the perceptual and pre-attentive neural level as a result of brief listen-and-repeat training in adult participants.</p

The N1 hypothesis and irrelevant sound:Evidence from token set effects

This study investigated how increases in the number of different types of sound (token set size) within a heard but ignored sequence influence brain activity and performance in a serial recall task (the irrelevant sound effect). We tested the hypothesis that brain processes affected by the refractory state of the neuronal populations involved in generating the auditory N1 play a role in the memory disruption produced by irrelevant sound. Auditory event-related potentials (ERPs) were recorded when volunteers performed a serial recall task that required remembering lists of visually presented numbers that were followed by a distractor-filled retention interval. The results showed that both increments in set size from 1 to 2 and from 2 to 5 elicited an increase of the N1 amplitude. Furthermore, increases in set size from 2 to 5, but not from 1 to 2, caused a significant decrease of the serial recall performance. This result suggested that, if N1 were to play a role in the disruption produced by irrelevant sound, the processes underlying the N1 wave may only serve as a necessary rather than a sufficient condition for disruption.Peer reviewe

Statistical language learning in neonates revealed by event-related brain potentials

<p>Abstract</p> <p>Background</p> <p>Statistical learning is a candidate for one of the basic prerequisites underlying the expeditious acquisition of spoken language. Infants from 8 months of age exhibit this form of learning to segment fluent speech into distinct words. To test the statistical learning skills at birth, we recorded event-related brain responses of sleeping neonates while they were listening to a stream of syllables containing statistical cues to word boundaries.</p> <p>Results</p> <p>We found evidence that sleeping neonates are able to automatically extract statistical properties of the speech input and thus detect the word boundaries in a continuous stream of syllables containing no morphological cues. Syllable-specific event-related brain responses found in two separate studies demonstrated that the neonatal brain treated the syllables differently according to their position within pseudowords.</p> <p>Conclusion</p> <p>These results demonstrate that neonates can efficiently learn transitional probabilities or frequencies of co-occurrence between different syllables, enabling them to detect word boundaries and in this way isolate single words out of fluent natural speech. The ability to adopt statistical structures from speech may play a fundamental role as one of the earliest prerequisites of language acquisition.</p

The MMN as a viable and objective marker of auditory development in CI users

In the present article, we review the studies on the use of the mismatch negativity (MMN) as a tool for an objective assessment of cochlear-implant (CI) functioning after its implantation and as a function of time of CI use. The MMN indexes discrimination of different sound stimuli with a precision matching with that of behavioral discrimination and can therefore be used as its objective index. Importantly, these measurements can be reliably carried out even in the absence of attention and behavioral responses and therefore they can be extended to populations that are not capable of behaviorally reporting their perception such as infants and different clinical patient groups. In infants and small children with CI, the MMN provides the only means for assessing the adequacy of the CI functioning, its improvement as a function of time of CI use, and the efficiency of different rehabilitation procedures. Therefore, the MMN can also be used as a tool in developing and testing different novel rehabilitation procedures. Importantly, the recently developed multi-feature MMN paradigms permit the objective assessment of discrimination accuracy for all the different auditory dimensions (such as frequency, intensity, and duration) in a short recording time of about 30 min. Most recently, such stimulus paradigms have been successfully developed for an objective assessment of music perception, too. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe

SISÄKORVAISTUTETTA KÄYTTÄVIEN AIKUISTEN TAPAHTUMASIDONNAISET JÄNNITEVASTEET

Sisäkorvaistutteiden (SI) ja niissä käytettyjen äänenkäsittelytekniikoidennopeasta kehityksestä huolimatta aikuisten SI-käyttäjien puheen havaitsemisenja äänteiden erottelemisen kyvyissä on tuntuvaa vaihtelua. Ääntensynnyttämien tapahtumasidonnaisten jännitevasteiden (ERP; event-relatedpotential) avulla voidaan tutkia kuuloinformaation käsittelyä aivokuorella.Tässä artikkelissa kuvataan aikuisten SI-käyttäjien kuntoutumista kortikaalistenvasteiden, etenkin mismatch negativity (MMN) -vasteen avulla.Asiasanat: Aikuiset, kuulo, sisäkorvaistute, tapahtumasidonnaiset jännitevasteet, MMNKeywords: Adults, audition, cochlear implant, event-related potentials, MMN

MISMATCH NEGATIVITY (MMN) -VASTE PUHEEN HAVAITSEMISEN HEIJASTAJANA

Selvitettäessä äidinkielen ja vieraiden kielten äänteiden havaitsemistaaivojen herätevasteisiin kuuluva mismatch negativity (MMN) on osoittautunuterinomaiseksi menetelmäksi behavioraalisten tutkimustulosten täydentäjänä.MMN-vaste syntyy mille tahansa havaittavissaolevalle muutokselle muutenhomogeenisessa ääniympäristössä. Se syntyy myös silloin, kun ääniärsykkeitäei tarkkailla, joten sillä voidaan tutkia jopa vauvojen kuulohavaintoa. MMNheijastaa paitsi äänten fysikaalisten erojen erottelukykyä, myös kielispesifejämuistijälkiä, jotka yleensä painottuvat aivojen vasempaan puoliskoon. MMN:lIä pystytään myös selvittämään vieraan kielen oppimisen vaikutuksia aivojenäänne-edustumiin. Erityisen hyödyllinen tämä aivojen reaktio on tutkittaessalapsen kielen kehitystä. Sen avulla on mm. osoitettu, että äidinkielelle tyypillisetvokaalikategoriat alkavat muodostua vauvoilla 6-12 kuukauden iässä.Avainsanat: puheäänteiden havaitseminen, kielen oppiminen, aivojenherätevasteet, mismatch negativity (MMN) -vasteThe mismatch negativity (MMN) component of the auditory event related potential(ERP) has proven to be very useful in investigating the perception of the speech soundsof the mother tongue and foreign languages. It is elicited by any discriminable changeoccurring in a homogeneous sound environment even when the subjeet is not attendingto the sounds. Therefore, it can be used for studying speech perception even in individualswith whom behavioural measurements are problematic. The MMN reflectsboth the discrimination of physical sound features and the presence of language-specificspeech-sound traces of the left cerebral hemisphere. Recently it has also been used to determinethe effects offoreign-language learning on the cortical speech-sound representations.Being an attention-independent response, the MMN is particularly useful for investigatingthe early development ofspeech perception. It has been shown, for example,that language-specific speech-sound traces develop between 6-12 months after birth.Keywords: speech perception, language learning, event-related brain potentials, mismatchnegativity (MMN

Learning-induced neural plasticity of speech processing before birth

Peer reviewe

Passive exposure to speech sounds induces long-term memory representations in the auditory cortex of adult rats

Experience-induced changes in the functioning of the auditory cortex are prominent in early life, especially during a critical period. Although auditory perceptual learning takes place automatically during this critical period, it is thought to require active training in later life. Previous studies demonstrated rapid changes in single-cell responses of anesthetized adult animals while exposed to sounds presented in a statistical learning paradigm. However, whether passive exposure to sounds can form long-term memory representations remains to be demonstrated. To investigate this issue, we first exposed adult rats to human speech sounds for 3 consecutive days, 12 h/d. Two groups of rats exposed to either spectrotemporal or tonal changes in speech sounds served as controls for each other. Then, electrophysiological brain responses from the auditory cortex were recorded to the same stimuli. In both the exposure and test phase statistical learning paradigm, was applied. The exposure effect was found for the spectrotemporal sounds, but not for the tonal sounds. Only the animals exposed to spectrotemporal sounds differentiated subtle changes in these stimuli as indexed by the mismatch negativity response. The results point to the occurrence of long-term memory traces for the speech sounds due to passive exposure in adult animals.Peer reviewe

Aging and non-native speech perception: A phonetic training study

Cognitive decline is evident in the elderly and it affects speech perception and foreign language learning. A listen-and-repeat training with a challenging speech sound contrast was earlier found to be effective in young monolingual adults and even in advanced L2 university students at the attentive and pre-attentive levels. This study investigates foreign language speech perception in the elderly with the same protocol used with the young adults. Training effects were measured with attentive behavioural measures (N=9) and with electroencephalography measuring the pre-attentive mismatch negativity (MMN) response (N=10). Training was effective in identification, but not in discrimination and there were no changes in the MMN. The most attention demanding perceptual functions which benefit from experience-based linguistic knowledge were facilitated through training, whereas preattentive processing was unaffected. The elderly would probably benefit from different training types compared to younger adults. Keywords: Training; Speech perception; Phonological processing; Aging; Mismatch negativity (MMN)</p