Biology subjects

Rothen, N.

Publications and source records attributed to Rothen, N..

4 recordsLinked to original sources

bioRxiv2025

Proficiency-Dependent and Dynamic Reorganization of Brain Networks During Children's Second Language Learning

Childrens second language (L2) vocabulary learning is often indexed with event-related potentials (ERPs) by the N400 incongruity effect, yet its stability in real classrooms is unclear. We recorded 64-channel EEG from 42 children (aged 9-15 years) during a translation-recognition task before and after a regular instructional vocabulary unit and sub-grouped children by baseline proficiency. We quantified the canonical N400 (300-500 ms, centroparietal region of interest; ROI) alongside electrical-neuroimaging indices of ERP strength and topography (Global Field Power, Global Map Dissimilarity, ERP template-map preponderance), using adult template maps from a prior study as a normative reference. Behaviorally, children showed large gains in vocabulary accuracy and higher discrimination sensitivity (d') in post-assessment. The classical N400 incongruity effect did not increase from pre- to post-learning. By contrast, global and topographic measures were learning-sensitive: Global Field Power increased across sessions and interacted with proficiency, and Global Map Dissimilarity showed main effects of session and proficiency as well as their interaction, indicating proficiency-dependent topographic reorganization. Adult normative template maps backfitted well; within the N400 window, high-proficiency children more consistently occupied an adult-like configuration; later ([~]650-800 ms), patterns also differentiated by proficiency and congruency. Relative to adults, children exhibited more diffuse topographies and stronger dependence on individual proficiency. In classroom settings, childrens L2 vocabulary learning is therefore more sensitively indexed by scalp topography and global field dynamics than by a single N400 amplitude, positioning electrical neuroimaging as a proficiency-dependent, classroom-relevant marker of L2 acquisition.

neuroscience↗

bioRxiv2025

Brain Network Differences in Second Language Learning Depend on Individual Competencies

Integrating new words into an existing semantic network is a core challenge of second language (L2) acquisition. We investigated how evidence-based learning strategies and individual performance shape the neurocognitive dynamics of vocabulary learning. Eighty- three adults with German or French as their native language (L1) learned 48 Finnish (L2) nouns over 14 days using a mobile app that systematically varied retrieval practice, corrective feedback, multisensory learning, and distributed learning. Before and after training, EEG was recorded during a translation recognition task designed to elicit the N400, an index of semantic integration. Vocabulary accuracy increased from 0.41% pre-learning to 75.5% post- learning (dz = 3.96), and the N400 incongruity effect increased significantly, F(1, 75) = 99.52, p < .001, {superscript 2}g = .32, reflecting successful integration of new L2 words into the mental lexicon. High performers showed larger N400 responses and distinct ERP template-map preponderance (i.e., the proportion of epoch time points assigned to a given template map) indicating more efficient and specialized neural processing. Despite systematic manipulation of learning strategies, no single approach yielded consistent behavioral or neural advantages, suggesting that overall exposure and cumulative practice--rather than any specific strategy-- were the key drivers of robust learning. ERP template-map analyses further revealed that learning not only amplified neural responses but also shifted the preponderance of maps in the N400 window, signaling a qualitative reorganization of semantic processing. These findings bridge cognitive neuroscience and language education, suggesting that the depth and success of vocabulary learning may depend more on the degree of integration achieved than on the specific instructional strategy employed.

neuroscience↗

bioRxiv2025

Test-Retest Reliability Analysis of Resting-state EEG Measures and Their Association with Long-Term Memory in Children and Adults

EEG resting-state measures, such as spectral power and microstates, have been associated with human long-term memory (LTM) performance. However, findings across studies are inconsistent and sometimes contradictory, likely due to a low reliability of the measures employed. These inconsistencies limit the interpretability and generalizability of results, emphasizing the need for a systematic evaluation of measure reliability. In this study, we addressed this gap by identifying the most reliable EEG resting-state measures and evaluating their predictive value for LTM performance in a second-language (L2) vocabulary learning paradigm. A group of children (N = 36) and adults (N = 90) participated in 2 studies on app-assisted learning of second language vocabulary. Participants completed a test on L2 vocabulary and a resting-state EEG recording (180 s eyes open) before and after learning a second language using a smartphone app. We used Intraclass Correlation Coefficients (ICC) to identify resting state EEG measures with satisfying test-retest reliability (ICC >= 0.75) and then assessed how these reliable measures are associated with L2 vocabulary learning representing LTM performance. Highest ICC values were found for oscillatory power in the alpha range and in the frequency of occurrences, duration and coverages of microstates. Calculations yielded ICC values of 0.84/0.86 (children/adults) for alpha power and 0.88/0.80 for microstate measures. Of these measures, only alpha power showed a positive correlation with LTM performance, but only in the adult population (r = 0.38, p < .01). No other measures were associated with LTM (all p > 0.05). Alpha power could thus serve as a stable and reliable marker of the neural mechanisms accounting for high LTM performance in the fully developed adult brain.

neuroscience↗

bioRxiv2020

Extensive Phenomenological Overlap between Induced and Naturally-Occurring Synaesthetic Experiences

Grapheme-colour synaesthesia (GCS) is defined by additional perceptual experiences, which are automatically and consistently triggered by specific inducing stimuli. The associative nature of GCS has motivated attempts to induce synaesthesia by means of associative learning. Two recent studies have shown that extensive associative training can generate not only behavioural (consistency and automaticity) and neurophysiological markers of GCS, but also synaesthesia-like phenomenology [1,2]. However, these studies provided only superficial descriptions regarding the training-related changes in subjective experience: they did not directly assess how closely induced synaesthetic experiences mirror those found in natural GCS. Here we report an extended qualitative analysis of the transcripts of the semi-structured interviews obtained following the completion of the associative training protocol used by [2]. In addition, we performed a comparable analysis of responses to an interview with a new population of natural occurring grapheme-colour synaesthetes (NOS), allowing us to directly compare the phenomenological dimensions of induced and naturally occurring synaesthetic experience. Our results provide an extensive addition to the description of the phenomenology of NOS experience, revealing a high degree of heterogeneity both within and across all experiential categories. Capitalising on this unique level of detail, we identified a number of shared experiential categories between NOS and induced synaesthesia-like (ISL) groups, including: stability of experience, location of colour experience, shape of co-occurring colour experience, relative strength of colour experience and automaticity of colour experience. Only the automaticity of colour experience differed significantly between the two groups: NOS experience was reported as being mostly automatic, whereas induced ISL were mostly described as being wilful. We observed three additional experiential categories relating to the automaticity of synaesthetic experience within the NOS group: contextually varied experience, semi-automatic experience and reflective association, which suggests that, as with other experiential categories, the automaticity of synaesthetic experience is also highly heterogeneous. Our results provide new evidence that that intensive training of letter-colour associations can alter conscious perceptual experiences in non-synaesthetes, and that such alterations produce synaesthesia-like phenomenology which substantially resembles similarities to natural grapheme-colour synaesthesia.

neuroscience↗