Neuroplasticity in the phonological system: The PMN and the N400 as markers for the perception of non-native phonemic contrasts by late second language learners.

Second language (L2) learners frequently encounter persistent difficulty in perceiving certain non-native sound contrasts, i.e., a phenomenon called "phonological deafness". However, if extensive L2 experience leads to neuroplastic changes in the phonological system, then the capacity to discriminate non-native phonemic contrasts should progressively improve. Such perceptual changes should be attested by modifications at the neurophysiological level. We designed an EEG experiment in which the listeners' perceptual capacities to discriminate second language phonemic contrasts influence the processing of lexical-semantic violations. Semantic congruency of critical words in a sentence context was driven by a phonemic contrast that was unique to the L2, English (e.g.,/ɪ/-/i:/, ship - sheep). Twenty-eight young adult native speakers of French with intermediate proficiency in English listened to sentences that contained either a semantically congruent or incongruent critical word (e.g., The anchor of theship/*sheepwas let down) while EEG was recorded. Three ERP effects were found to relate to increasing L2 proficiency: (1) a left frontal auditory N100 effect, (2) a smaller fronto-central phonological mismatch negativity (PMN) effect and (3) a semantic N400 effect. No effect of proficiency was found on oscillatory markers. The current findings suggest that neuronal plasticity in the human brain allows for the late acquisition of even hard-wired linguistic features such as the discrimination of phonemic contrasts in a second language. This is the first time that behavioral and neurophysiological evidence for the critical role of neural plasticity underlying L2 phonological processing and its interdependence with semantic processing has been provided. Our data strongly support the idea that pieces of information from different levels of linguistic processing (e.g., phonological, semantic) strongly interact and influence each other during online language processing.

A combined forced-attention dichotic listening - Go/Nogo task to assess response inhibition and interference suppression: An auditory event-related potential investigation.

OBJECTIVE: Interference suppression and response inhibition are distinct effortful inhibitory processes. Yet they rely on partly overlapping neural substrates. Their independence was studied using an auditory paradigm. METHOD: Continuous EEG was recorded in 16 adults and event-related potentials (ERPs) were analyzed in a new dichotic listening - Go/Nogo task. Attention was directed either to the right dominant ear (forced-right blocks [FR]) or to the left ear (forced-left blocks [FL]). The Go/Nogo task required a motor response only to the standard word played to the selected ear; the nonselected ear was simultaneously presented with the same word (Go condition) or with a deviant (Incongruent Go condition). In the Nogo condition, a deviant was presented to the selected ear while the standard was played to the nonselected ear. Effortful interference suppression was expected only in the FL blocks to override the automatic processing of distractors in the dominant ear. RESULTS: When no effortful interference suppression was necessary (FR blocks) in the Nogo condition, the N2 and P3 increase probably reflected two subcomponents of response inhibition (response restraint and response cancellation) and the P2 decrease probably reflected an early inhibitory mechanism (sensory gating). When effortful interference suppression was necessary (FL blocks), there was no Nogo-N2 (i.e., no response restraint). Interference suppression (Incongruent Go condition minus Go condition) also increased the N2 and P3, but did not modulate the P2. CONCLUSIONS: This new paradigm confirms the partial overlap between response inhibition and effortful interference suppression and points out specific features of their subcomponents. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Atypical hemispheric asymmetries for the processing of phonological features in children with rolandic epilepsy.

We assessed language lateralization in 177 healthy 4- to 11-year-old children and adults and atypical asymmetries associated with unilateral epileptic foci in 18 children with benign epilepsy with centrotemporal spikes (BECTS). Dichotic listening results revealed two indices of immature functional asymmetry when the focus was left-sided (BECTS-L). First, children with BECTS-L did not show left hemisphere dominance for the processing of place of articulation, which was recorded in children with BECTS-R and control children. On the contrary, healthy children exhibited a gradual increase in left hemisphere dominance for place processing during childhood, which is consistent with the shift from global to finer-grained acoustic analysis predicted by the Developmental Weighting Shift model. Second, children with BECTS-L showed atypical left hemisphere involvement in the processing of the voiced value (+V), associated with a long acoustic event in French stop consonants, whereas right hemisphere dominance increased with age for +V processing in healthy children. BECTS-L, therefore, interferes with the development of left hemisphere dominance for specific phonological mechanisms.

Hemispheric asymmetries depend on the phonetic feature: a dichotic study of place of articulation and voicing in French stops.

Dichotic listening experiments show a right-ear advantage (REA), reflecting a left-hemisphere (LH) dominance. However, we found a decrease in REA when the initial stop consonants of two simultaneous French CVC words differed in voicing rather than place of articulation (Experiment 1). This result suggests that the right hemisphere (RH) is more involved in voicing than in place processing. The voiceless-voiced contrast is realised as short positive vs. long negative VOT in French stop consonants, but as long vs. short positive VOT in English. We tested whether the relative involvement of the LH and RH is governed by their respective putative specialisation for short and long events. As expected, in French, the REA decreased when a voiced stop was presented to the left ear and a voiceless stop to the right ear (+V-V), whereas the REA had been shown to decrease for (-V+V) pairs in English. Additionally, voiced stops were more frequently reported among blend responses when a voiced consonant was presented to the left ear. In Experiment 2, VCV pairs were used to reduce the stimulus dominance effect for voiced consonants, which probably contributed to the low REA for (+V-V) pairs in Experiment 1. The reduction of the REA due to a voicing difference was maintained, which provides evidence for the relative independence of the mechanisms responsible for stimulus dominance and perceptual asymmetries in dichotic listening. The results are discussed in the light of the Asymmetric Sampling in Time (AST) model.