Publications

Abstract

The field of psycholinguistics is currently experiencing an explosion of interest in the analysis of neural oscillations—rhythmic brain activity synchronized at different temporal and spatial levels. Given that language comprehension relies on a myriad of processes, which are carried out in parallel in distributed brain networks, there is hope that this methodology might bring the field closer to understanding some of the more basic (spatially and temporally distributed, yet at the same time often overlapping) neural computations that support language function. In this review, we discuss existing proposals linking oscillatory dynamics in different frequency bands to basic neural computations and review relevant theories suggesting associations between band-specific oscillations and higher-level cognitive processes. More or less consistent patterns of oscillatory activity related to certain types of linguistic processing can already be derived from the evidence that has accumulated over the past few decades. The centerpiece of the current review is a synthesis of such patterns grouped by linguistic phenomenon. We restrict our review to evidence linking measures of oscillatory
power to the comprehension of sentences, as well as linguistically (and/or pragmatically) more complex structures. For each grouping, we provide a brief summary and a table of associated oscillatory signatures that a psycholinguist might expect to find when employing a particular linguistic task. Summarizing across different paradigms, we conclude that a handful of basic neural oscillatory mechanisms are likely recruited in different ways and at different times for carrying out a variety of linguistic computations.

Abstract

Reinstatement of memory-related neural activity measured with high temporal precision potentially provides a useful index for real-time monitoring of the timing of activation of memory content during cognitive processing. The utility of such an index extends to any situation where one is interested in the (relative) timing of activation of different sources of information in memory, a paradigm case of which is tracking lexical activation during language processing. Essential for this approach is that memory reinstatement effects are robust, so that their absence (in the average) definitively indicates that no lexical activation is present. We used electroencephalography to test the robustness of a reported subsequent memory finding involving reinstatement of frequency-specific entrained oscillatory brain activity during subsequent recognition. Participants learned lists of words presented on a background flickering at either 6 or 15 Hz to entrain a steady-state brain response. Target words subsequently presented on a non-flickering background that were correctly identified as previously seen exhibited reinstatement effects at both entrainment frequencies. Reliability of these statistical inferences was however critically dependent on the approach used for multiple comparisons correction. We conclude that effects are not robust enough to be used as a reliable index of lexical activation during language processing.

Abstract

Oscillatory neural dynamics have been steadily receiving more attention as a robust and temporally precise signature of network activity related to language processing. We have recently proposed that oscillatory dynamics in the beta and gamma frequency ranges measured during sentence-level comprehension might be best explained from a predictive coding perspective. Under our proposal we related beta oscillations to both the maintenance/change of the neural network configuration responsible for the construction and representation of sentence-level meaning, and to top–down predictions about upcoming linguistic input based on that sentence-level meaning. Here we zoom in on these particular aspects of our proposal, and discuss both old and new supporting evidence. Finally, we present some preliminary magnetoencephalography data from an experiment comparing Dutch subject- and object-relative clauses that was specifically designed to test our predictive coding framework. Initial results support the first of the two suggested roles for beta oscillations in sentence-level language comprehension.

Abstract

For native speakers, many studies suggest a link between oscillatory neural activity in the beta frequency range and syntactic processing. For late second language (L2) learners on the other hand, the extent to which the neural architecture supporting syntactic processing is similar to or different from that of native speakers is still unclear. In a series of four experiments, we used electroencephalography to investigate the link between beta oscillatory activity and the processing of grammatical gender agreement in Dutch determiner-noun pairs, for Dutch native speakers, and for German L2 learners of Dutch. In Experiment 1 we show that for native speakers, grammatical gender agreement violations are yet another among many syntactic factors that modulate beta oscillatory activity during sentence comprehension. Beta power is higher for grammatically acceptable target words than for those that mismatch in grammatical gender with their preceding determiner. In Experiment 2 we observed no such beta modulations for L2 learners, irrespective of whether trials were sorted according to objective or subjective syntactic correctness. Experiment 3 ruled out that the absence of a beta effect for the L2 learners in Experiment 2 was due to repetition of the target nouns in objectively correct and incorrect determiner-noun pairs. Finally, Experiment 4 showed that when L2 learners are required to explicitly focus on grammatical information, they show modulations of beta oscillatory activity, comparable to those of native speakers, but only when trials are sorted according to participants’ idiosyncratic lexical representations of the grammatical gender of target nouns. Together, these findings suggest that beta power in L2 learners is sensitive to violations of grammatical gender agreement, but only when the importance of grammatical information is highlighted, and only when participants' subjective lexical representations are taken into account.