Syntax through the looking glass: A review on two-word linguistic processing across behavioral, neuroimaging and neurostimulation studies

In recent years a growing number of studies on syntactic processing has employed basic two-word constructions (e.g., “the tree”) to characterize the fundamental aspects of linguistic composition. This large body of evidence allows, for the first time, to closely examine which cognitive processes and neural substrates support the combination of two syntactic units into a more complex one, mirroring the nature of combinatory operations described in theoretical linguistics. The present review comprehensively examines behavioural, neuroimaging and neurostimulation studies investigating basic syntactic composition, covering more than forty years of psycho- and neuro-linguistic research. Across several paradigms, four key features of syntactic composition have emerged: (1) the rule-based and (2) automatic nature of the combinatorial process, (3) a central role of Broca’s area and the posterior temporal lobe in representing and combining syntactic features, and (4) the reliance on efficient bottom-up integration rather than top-down prediction

Syntax through the looking glass: A review on two-word linguistic processing across behavioral, neuroimaging and neurostimulation studies

In recent years a growing number of studies on syntactic processing has employed basic two-word constructions (e.g., “the tree”) to characterize the fundamental aspects of linguistic composition. This large body of evidence allows, for the first time, to closely examine which cognitive processes and neural substrates support the combination of two syntactic units into a more complex one, mirroring the nature of combinatory operations described in theoretical linguistics. The present review comprehensively examines behavioural, neuroimaging and neurostimulation studies investigating basic syntactic composition, covering more than 40 years of psycho- and neuro-linguistic research. Across several paradigms, four key features of syntactic composition have emerged: (1) the rule-based and (2) automatic nature of the combinatorial process, (3) a central role of Broca’s area and the posterior temporal lobe in representing and combining syntactic features, and (4) the reliance on efficient bottom-up integration rather than top-down prediction

Testing automaticity of syntax using subliminal priming: A behavioural assessment in the German language

Neurophysiological studies investigated the automaticity of syntactic processing under conscious conditions. However, it remains largely unknown whether syntactic analysis proceeds outside of conscious awareness. In this study, we employed a subliminal syntactic priming paradigm to address the automaticity of syntax in minimal phrases. We run four behavioural experiments to test whether recognition of a target’s category (noun or verb) could be influenced by its syntactic relationship with a prime (“a” or “he”). Prime-target relationship was either congruent (“a” + noun, “he” + verb) or incongruent (“a” + verb, “he” + noun). In the pilot and Experiments 1 and 2, verbs included an overt morphological cue (the suffix “-t”), which was absent in Experiment 3. In Experiment 2 we included nonword primes as a baseline condition, to remove processing differences between nouns and verbs independent of syntactic context. Experiments 1 and 2 revealed a subliminal syntactic priming effect: words preceded by syntactically congruent masked primes were processed faster than words preceded by incongruent primes. When no morphological cue was present (Experiment 3), we found no subliminal syntactic priming. Experiment 3 revealed an inhibitory nature of syntactic priming: incongruent primes slowed down the processing of nouns and verbs compared to nonword primes. Our study shows that abstract syntactic representations might be accessed unconsciously in an automatic fashion. Furthermore, the results indicate the role of morphological cues in the early and automatic steps of syntactic analysis

Testing automaticity of syntax using subliminal priming: A behavioral assessment in German language

INTRODUCTION. Previous research on the automaticity of initial syntactic structure building during sentence comprehension employed paradigms involving conscious processing (Friederici, 2011; Hahne & Friederici, 1999). In order to better understand the rapid nature of early phrase structure building, in the present behavioral study we addressed syntactic processing in the absence of conscious awareness. It has been argued that the automatic nature of early syntactic processes might be strongly connected to humans’ predictive capacity to generate syntactic expectations upon the upcoming material (Lau et al., 2006). Following a recent study by Berkovitch and Dehaene (2019), we employed subliminal syntactic priming to test the connection between our predictive syntactic capacity and the automaticity of syntactic analysis. METHODS. We run three behavioral experiments — one pilot (N = 19) determining the adequate effect size, followed by two main experiments (N = 43, N = 40) — to explore the early influence of congruent primes (er “he”, ein “a”) on the processing of German verbs and nouns. Conscious perception of the primes was induced using unmasked syntactic priming, while unconscious perception was induced using subliminally presented masked primes. The first main experiment included nouns and verbs with the ending -t, which is part of the stem for nouns but an inflectional suffix for verbs. Given that numerous studies reported a rapid decomposition of morphologically complex words into the stem and affixes (Beyersmann et al., 2011; Beyersmann et al., 2016), to exclude a possible influence of the suffix “-t” on grammatical categorization, in the second experiment we only included nouns and verbs with various endings and eliminated overt inflectional morphology by using irregular past tense verbs. The (un)awareness of the primes was controlled in a prime visibility task in both studies. RESULTS. In the first main experiment, we found a strong prime × category interaction, which was independent of masking (p < 0.001), and which was further confirmed by a congruency effect in both masked and unmasked conditions. Thus, the pronoun facilitated the processing of verbs, whereas the determiner facilitated the processing of nouns even when syntactic context was not consciously perceived. The second main experiment confirmed the prime × category interaction, together with a main effect of category — pointing towards late processing mechanisms at work by irregular verbal forms without overt inflectional morphology. CONCLUSION. Overall, both experiments suggest that the pronoun and the determiner pre-activate an appropriate abstract syntactic category, facilitating the processing of upcoming nouns and verbs. The results indicate that abstract syntactic representations might be accessed unconsciously in an automatic fashion, thus providing empirical basis for future imaging studies focusing on the neural behavior of early structure building processing in the human brain. References: Berkovitch & Dehaene, Cogn Psychol, 2019; Beyersmann et al., Psychon Bull Rev, 2011; Beyersmann et al., Psychon Bull Rev, 2016; Friederici, Physiol Rev, 2011; Hahne & Friederici, Journal of Cogn Neurosc, 1999; Lau et al., Brain and Language, 2006

Organochlorine compounds (Polychlorinated biphenyls and Pesticides) and Polycyclic aromatic hydrocarbons in populations of Hexaplex trunculus affected by imposex in the lagoon of Venice, Italy

Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides, and polycyclic aromatic hydrocarbons (PAHs) were measured in gastropods from the Lagoon of Venice, Italy. The visceral coil and the rest of the soft body of organisms (Hexaplex trunculus) sampled at two stations inside the lagoon and three stations on the seaward side were analyzed to evaluate their contamination levels. Preferential accumulation of PCBs and pesticides in the visceral coil (>80%) compared with the rest of the soft body was observed, whereas on average, PAHs showed no preferential partitioning. Differences between levels of organochlorine contaminants in the gastropods highlighted a gradient of pollution from the stations inside the lagoon (PCBs, 45-363 ng/g; pesticides, 4-51 ng/g) to the sea (PCBs, 13-131 ng/g; pesticides, 2-29 ng/g). The possible role of the three classes of contaminants, in addition to that of organotin compounds (OTCs), previously analyzed in the same samples, in causing one of the anatomic modifications because of imposex in this gastropod also was studied. A modeling approach by partial least squares (PLS) in latent variables was applied to explain the penis length of imposex-affected females with concentrations of organic pollutants. The synergistic role of PCBs, pesticides, and OTCs was evidenced, whereas the contribution of PAHs appeared to be very low

Online neurostimulation of Broca's area does not interfere with syntactic predictions: A combined TMS-EEG approach to basic linguistic combination

Categorical predictions have been proposed as the key mechanism supporting the fast pace of syntactic composition in human language. Accordingly, grammar-based expectations facilitate the analysis of incoming syntactic information—e.g., hearing the determiner “the” enhances the prediction of a noun—which is then checked against a single or few other word categories. Previous functional neuroimaging studies point towards Broca’s area in the left inferior frontal gyrus (IFG) as one fundamental cortical region involved in categorical prediction during on-line language processing. Causal evidence for this hypothesis is however still missing. In this study, we combined Electroencephalography (EEG) and Transcranial Magnetic Stimulation (TMS) to test whether Broca’s area is functionally relevant in predictive mechanisms for language. Specifically, we transiently perturbed Broca’s area during the categorical prediction phase in two-word constructions, while simultaneously measuring the Event-Related Potential (ERP) correlates of syntactic composition. We reasoned that if Broca’s area is involved in predictive mechanisms for syntax, disruptive TMS during the processing of the first word (determiner/pronoun) would mitigate the difference in ERP responses for predicted and unpredicted categories when composing basic phrases and sentences. Contrary to our hypothesis, perturbation of Broca’s area at the predictive stage did not affect the ERP correlates of basic composition. The correlation strength between the electrical field induced by TMS and the magnitude of the EEG response on the scalp further confirmed this pattern. We discuss the present results in light of an alternative account of the role of Broca’s area in syntactic composition, namely the bottom-up integration of words into constituents

Towards a causal role of Broca's area in language: A TMS-EEG study on syntactic prediction

Introduction: In language comprehension, the analysis of the grammatical category of words occurs during the very early phase of processing (Friederici, 2011). When the category of incoming words violates syntactic rules, increased negativities are observed compared to grammatical constructions (Early Left Anterior Negativity – ELAN, Friederici et al., 1993); Early Syntactic Negativity – ESN, Hasting & Kotz, 2008). The early latencies of these components have been attributed to the presence of structural predictions (Lau et al., 2006). For example, after hearing “The”, a noun, alone or with an adjective, is expected to build a phrase. Accordingly, the ELAN and ESN effects would reflect a mismatch between the predicted category and the observed ungrammatical one. Functional studies implicated Broca’s area in syntactic categorical prediction (Bonhage et al., 2015), but causal evidence for this claim is still missing. We tested this hypothesis by simultaneously combining Transcranial Magnetic Stimulation (TMS) and Electroencephalography (EEG) in a two-word ESN paradigm. With TMS, we transiently perturbed activity in Broca’s area at the stage of prediction (e.g., “the”) and measured the negativity elicited by predicted (e.g., noun) and unpredicted (e.g., verb) categories. We hypothesized that disruption of Broca’s area during the processing of the first word would prevent an ESN effect (ungrammatical vs. grammatical) on the second word, as no prediction is initiated. Therefore, categorical effects on the second word would be similar for both grammatical and ungrammatical items. Methods: We employed a German version of the auditory two-word ESN paradigm. The first word could either be the determiner “Ein” (a, predicting a noun) or the pronoun “Er” (he, predicting a verb). The second word could either be a noun or a verb. Two types of two-word constructions were therefore included: grammatical (“Ein” and a noun, “Er” and a verb) and ungrammatical (“Ein” and a verb, “Er” and a noun). To selectively interfere with the predictive stage, we transiently perturbed activity in Broca’s area by means of a 10 Hz train of five TMS pulses starting at the onset of the first word. Three stimulation conditions were included: Broca’s area (target site) and two control conditions (superior parietal lobe and sham stimulation), with the order counterbalanced across subjects. Data from twenty-nine German speakers entered the final analysis (fifteen female; mean age: 27.1 years, standard deviation: 4.1 years). The statistical analysis focused on the second word. We analyzed the main effect of grammaticality (ESN effect) and its modulation by TMS (grammaticality*TMS interaction) with cluster-based permutation tests (Maris & Oostenveld, 2007). By employing state-of-the-art electrical field modelling (Weise et al., 2020), we further correlated the TMS-induced electrical field in Broca’s area with changes in the ESN effect relative to the sham condition. Results: The cluster-based permutation test revealed a main effect of grammaticality, with the presence of a significant early negative cluster (approximately from 190 to 430ms, P .5, cluster-corrected). No significant correlation was found between changes in the ESN effect and the TMS-induced electrical field in Broca’s area (r = 0.142, p > 0.1, BF01 = 3.302). Conclusions: The main effect of grammaticality is consistent with an early analysis of word category, followed by late repairing processes (Friederici, 2011) in case of ungrammaticality. The lack of a significant grammaticality*TMS interaction suggests that Broca’s area may not be causally involved in categorical prediction. Our findings are compatible with functional studies proposing that this region might be involved in the bottom-up integration of words into syntactic structures (Bhattasali et al., 2019)

Exchange interaction effects in inter-Landau level Auger scattering in a two-dimensional electron gas

We consider the influence of spin effects on the inter-Landau level electron-electron scattering rate in a two-dimensional electron gas. Due to the exchange spin splitting, the Landau levels are not equidistant. This leads to the suppresion of Auger processes and a nonlinear dependence of the lifetime on the concentration of the excited electrons even at very low excitation levels.Comment: 10 pages, 3 figure

Physical Conditions in Circumstellar Gas surrounding SN 1987A 12 Years After Outburst

Two-dimensional spectra of Supernova 1987A were obtained on 1998 November 14-15 (4282 days after outburst) with the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST). The slit sampled portions of the inner circumstellar ring at the east and west ansae as well as small sections of both the northern and southern outer rings. The temperature and density at these locations are estimated by nebular analysis of [N II], [O III], and [S II] emission line ratios, and with time-dependent photoionization/recombination models. The results from these two methods are mutually consistent. The electron density in the inner ring is ~ 4000 cm-3 for S II, with progressively lower densities for N II and O III. The electron temperatures determined from [N II] and [O III] line ratios are ~11,000 K and \~22,000 K, respectively. These results are consistent with evolutionary trends in the circumstellar gas from similar measurements at earlier epochs. We find that emission lines from the outer rings come from gas of lower density (n_e \la 2000 cm-3) than that which emits the same line in the inner ring. The N/O ratio appears to be the same in all three rings. Our results also suggest that the CNO abundances in the northern outer ring are the same as in the inner ring, contrary to earlier results of Panagia et al. (1996). Physical conditions in the southern outer ring are less certain because of poorer signal-to-noise data. The STIS spectra also reveal a weak Ha emission redshifted by ~100 km s-1 at p.a. 103\arcdeg that coincides with the recently discovered new regions that are brightening (Lawrence et al. 2000). This indicates that the shock interaction in the SE section of the inner ring commenced over a year before it became apparent in HST images.Comment: 25 pages, 6 figures, to appear in December 1, 2000 Astrophysical Journa