Publications

Abstract

Models on L3/Ln acquisition differ with respect to how they envisage degree (holistic
vs. selective transfer of the L1, L2 or both) and/or timing (initial stages vs. development) of how
the influence of source languages unfolds. This study uses EEG/ERPs to examine these models,
bringing together two types of bilinguals: heritage speakers (HSs) (Italian-German, n = 15) compared
to adult L2 learners (L1 German, L2 English, n = 28) learning L3/Ln Latin. Participants were trained
on a selected Latin lexicon over two sessions and, afterward, on two grammatical properties: case
(similar between German and Latin) and adjective–noun order (similar between Italian and Latin).
Neurophysiological findings show an N200/N400 deflection for the HSs in case morphology and a
P600 effect for the German L2 group in adjectival position. None of the current L3/Ln models predict
the observed results, which questions the appropriateness of this methodology. Nevertheless, the
results are illustrative of differences in how HSs and L2 learners approach the very initial stages of
additional language learning, the implications of which are discussed

Abstract

The present study uses EEG time-frequency representations (TFRs) with a Flanker task to investigate if and how individual differences in bilingual language experience modulate neurocognitive outcomes (oscillatory dynamics) in two bilingual group types: late bilinguals (L2 learners) and early bilinguals (heritage speakers—HSs). TFRs were computed for both incongruent and congruent trials. The difference between the two (Flanker effect vis-à-vis cognitive interference) was then (1) compared between the HSs and the L2 learners, (2) modeled as a function of individual differences with bilingual experience within each group separately and (3) probed for its potential (a)symmetry between brain and behavioral data. We found no differences at the behavioral and neural levels for the between-groups comparisons. However, oscillatory dynamics (mainly theta increase and alpha suppression) of inhibition and cognitive control were found to be modulated by individual differences in bilingual language experience, albeit distinctly within each bilingual group. While the results indicate adaptations toward differential brain recruitment in line with bilingual language experience variation overall, this does not manifest uniformly. Rather, earlier versus later onset to bilingualism—the bilingual type—seems to constitute an independent qualifier to how individual differences play out.

Abstract

Herein, we contextualize, problematize, and offer some insights for moving beyond the problem of monolingual comparative normativity in (psycho) linguistic research on bilingualism. We argue that, in the vast majority of cases, juxtaposing (functional) monolinguals to bilinguals fails to offer what the comparison is supposedly intended to do: meet the standards of empirical control in line with the scientific method. Instead, the default nature of monolingual comparative normativity has historically contributed to inequalities in many facets of bilingualism research and continues to impede progress on multiple levels. Beyond framing our views on the matter, we offer some epistemological considerations and methodological alternatives to this standard practice that improve empirical rigor while fostering increased diversity, inclusivity, and equity in our field.

Abstract

Oligodendrocyte gene expression is downregulated in stress-related neuropsychiatric disorders,
including depression. In mice, chronic social stress (CSS) leads to depression-relevant changes
in brain and emotional behavior, and the present study shows the involvement of oligodendrocytes in this model. In C57BL/6 (BL/6) mice, RNA-sequencing (RNA-Seq) was conducted with
prefrontal cortex, amygdala and hippocampus from CSS and controls; a gene enrichment database for neurons, astrocytes and oligodendrocytes was used to identify cell origin of deregulated genes, and cell deconvolution was applied. To assess the potential causal contribution of
reduced oligodendrocyte gene expression to CSS effects, mice heterozygous for the oligodendrocyte gene cyclic nucleotide phosphodiesterase (Cnp1) on a BL/6 background were studied;
a 2 genotype (wildtype, Cnp1+/−
) × 2 environment (control, CSS) design was used to investigate
effects on emotional behavior and amygdala microglia. In BL/6 mice, in prefrontal cortex and
amygdala tissue comprising gray and white matter, CSS downregulated expression of multiple
oligodendroycte genes encoding myelin and myelin-axon-integrity proteins, and cell deconvolution identified a lower proportion of oligodendrocytes in amygdala. Quantification of oligodendrocyte proteins in amygdala gray matter did not yield evidence for reduced translation,
suggesting that CSS impacts primarily on white matter oligodendrocytes or the myelin transcriptome. In Cnp1 mice, social interaction was reduced by CSS in Cnp1+/− mice specifically;
using ionized calcium-binding adaptor molecule 1 (IBA1) expression, microglia activity was
increased additively by Cnp1+/− and CSS in amygdala gray and white matter. This study provides back-translational evidence that oligodendrocyte changes are relevant to the pathophysiology and potentially the treatment of stress-related neuropsychiatric disorders.

Abstract

The anterior cingulate cortex (ACC) and the dorsolateral prefrontal cortex (DLPFC) are involved in conflict detection and
conflict resolution, respectively. Here, we investigate how lifelong bilingualism induces neuroplasticity to these structures by
employing a novel analysis of behavioural performance. We correlated grey matter volume (GMV) in seniors reported by
Abutalebi et al. (2015) with behavioral Flanker task performance fitted using the diffusion model (Ratcliff, 1978). As
predicted, we observed significant correlations between GMV in the DLPFC and Flanker performance. However, for
monolinguals the non-decision time parameter was significantly correlated with GMV in the left DLPFC, whereas for
bilinguals the correlation was significant in the right DLPFC. We also found a significant correlation between age and GMV
in left DLPFC and the non-decision time parameter for the conflict effect for monolinguals only.
We submit that this is due to cumulative demands on cognitive control over a lifetime of bilingual language processing