ORCID Profile
0000-0001-8501-6076
Current Organisation
University of Reading
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Publisher: Informa UK Limited
Date: 04-2013
Publisher: Frontiers Media SA
Date: 04-05-2017
Publisher: American Physical Society (APS)
Date: 10-2000
Abstract: We apply symbolic dynamics techniques such as word statistics and measures of complexity to nonstationary and noisy multivariate time series of electroencephalograms (EEG) in order to estimate event-related brain potentials (ERP). Their significance against surrogate data as well as between different experimental conditions is tested. These methods are validated by simulations using stochastic dynamical systems with time-dependent control parameters and compared with traditional ERP-analysis techniques. Continuous EEG data are cut into epochs according to stimuli events presented to the subjects. These ensembles of time series can be considered as ensembles of trajectories given by some dynamical systems. We employ a statistical mechanics approach motivated by the Frobenius-Perron equation and apply it to coarse-grained symbolic descriptions of the dynamics. We develop time-dependent measures of complexity founded on running cylinder sets and show that these quantities are able to distinguish simulated data obtained by different control parameters as well as experimental data between different experimental conditions. As a first finding, our approach restores the well-known ERP components and it reveals additionally qualitative changes in the EEG that cannot be detected by means of the traditional techniques. We criticize the prerequisites of the traditional approach to ERP analysis and propose to consider ERP instead in terms of dynamical system theory and information theory.
Publisher: Center for Open Science
Date: 25-08-2020
Abstract: Statistical properties of language provide important cues for language learning and may be processed by domain-general cognitive systems. We investigated the relationship between implicit statistical learning (the unconscious detection of statistical regularities in input) and language production. Twenty typically developing (TD) children and nine children with acquired language disorders (ALD) (aged 6 to 18 years) took part in a Boston Cookie Theft picture description task. Using a computerized analysis, we investigated statistical properties, such as usage frequency of words and collocation strength of word combinations. Participants also completed a non-linguistic serial reaction time (SRT) task, which tested non-verbal, implicit statistical learning in the visual-motor modality. We determined age effects, and compared language production and SRT performance between both groups. Older TD children produced more connected language, more words, less frequent function words, more rare or novel combinations, and showed better statistical learning. Children with ALD produced less connected language, more weakly collocated combinations, displayed less lexical ersity and showed poorer statistical learning. Post-hoc analyses found correlations between statistical learning and statistical properties of spoken language. Given the rarity and heterogeneity of children with ALD, group size was small and the study should be considered exploratory. However, we note that results are compatible with the view that language production draws on statistical learning and that impairment of statistical learning can be related to language disorders. [This is an original manuscript of an article published by Taylor & Francis in Speech, Language and Hearing on 20 August 2021, available online: 0.1080/2050571X.2021.1954837]
Publisher: Elsevier BV
Date: 03-2011
Publisher: Elsevier BV
Date: 05-1988
DOI: 10.1016/0093-934X(88)90123-X
Abstract: The ability of right-brain-damaged (RBD) subjects to correctly insert a word into a well-formed stimulus sentence was tested. Subjects also performed three evaluative tasks designed to establish their degree of general cognitive impairment. The performance of RBD subjects on these tasks was compared to that of left-brain-damaged (LBD) and non-brain-damaged (NBD) subjects. Although RBD subjects outperformed LBD subjects on the language-related evaluative tasks, the RBD group was significantly more impaired on a subset of the insertion task. This subset included items which required reassignment of the syntactic status of elements in the stimulus sentence in order for the insertion to be carried out. The results of this study permit refinement of the common characterization of RBD in iduals as rigid in their interpretation of meaning and indicate right-hemisphere involvement in aspects of the grammar previously thought to be inaccessible to it.
Publisher: Frontiers Media SA
Date: 2015
Publisher: Elsevier BV
Date: 10-2002
DOI: 10.1016/S0010-0277(02)00126-9
Abstract: In a study using event-related brain potentials, we show that the current characterization of the P600 component as an indicator of revision processes (reanalysis and repair) in sentence comprehension must be extended to include the recognition of syntactic ambiguity. By comparing the processing of ambiguous and unambiguous sentence constituents in German, we show that the P600 is elicited when our language processing system has syntactic alternatives at a certain item given in the input string. That the P600 is sensitive to syntactic ambiguity adds crucial evidence to current debates in psycholinguistic modelling, as the results clearly favour parallel models of syntactic processing which assume that ambiguity is recognized and costly.
Publisher: Springer Science and Business Media LLC
Date: 06-06-2008
Publisher: Elsevier BV
Date: 08-1995
Abstract: This paper examines aggrammatics' interpretation of quantificationally ambiguous sentences. Although agrammatics are capable of recognizing quantificational ambiguities, they ascribe nonstandard entailments to those sentences involving universal quantification. Since quantificational ambiguity arises from movement of quantifiers at LF, doubt is cast on accounts of agrammatic behavior that rely on an inability to interpret moved constituents. Furthermore, the agrammatics are seen to improve in their thematic interpretation of arguments in reversible passive constructions and relatives if one of the arguments is universally quantified. The nonstandard entailments and improved performance on passive and relatives are accounted for via an elaboration of event semantics in which we propose that the agrammatic treats the event variable associated with a verb as nominal.
Publisher: Unpublished
Date: 2017
Publisher: Elsevier BV
Date: 11-2012
Publisher: Springer Science and Business Media LLC
Date: 21-02-2019
Publisher: Center for Open Science
Date: 19-01-2023
Abstract: In this paper, we explore the extraction of recursive nested structure in the processing of self-similar binary sequences generated by two Lindenmayer grammars: the Fibonacci grammar and the Skip grammar. In each of these grammars only sequential order information marks the hierarchical structure. Although closely related, these grammars differ from a formal point of view: the Fibonacci grammar is perfectly scale-free and presents an isomorphism between its surface and derivational properties while the Skip grammar, although also self-similar, does not present this isomorphism. Our goal was to explore the influence of these formal differences on the extraction of hierarchical structure by the participants. To this end, we implemented these grammars in a serial reaction time task. The results show that in both the Fibonacci grammar and the Skip grammar, participants elaborated a hierarchical structure from the signal. This suggests the involvement of at least partially similar mechanisms during processing. However, some processing differences remained that cannot be explained by the hypotheses proposed so far regarding the processing of strings generated by L-systems. We hypothesize that these effects would be due to the self-similarity of the signal which would act as a reinforcement of the structure elaborated by the participants.
Publisher: World Scientific Pub Co Pte Ltd
Date: 02-2004
DOI: 10.1142/S0218127404009296
Abstract: The study of language, its processing and its bearing on human cortical processes are all extensive domains of investigation in their own right. In this overview tutorial we limit ourselves to a s le of core illustrative issues. Our central aim is to demonstrate how complexity within the language faculty arises from two a priori distinct sources: the computational complexity inherent in the grammar of the language system itself and the procedural complexity resulting from marshalling processing resources in order to produce or interpret utterances that correspond to the grammar. Distinguishing between these two sources of complexity is a current goal in investigations of the human language faculty. The combination of quantitative approaches with newer qualitative approaches to the analysis of electro-cortical behavior associated with carefully controlled language paradigms represents a new approach to clarifying this central issue.
Publisher: Center for Open Science
Date: 19-07-2022
Abstract: In this article, we explore the extraction of recursive nested structure in the processing of binary sequences. Our aim was to determine whether the brain learns the higher order regularities of a highly simplified input where only sequential order information marks the hierarchical structure. To this end, we implemented sequence generated by the Fibonacci grammar in a serial reaction time task. This deterministic grammar generates aperiodic but self-similar sequences. The combination of these two properties allowed us to evaluate hierarchical learning while controlling for the use of low-level strategies like detecting recurring patterns. The deterministic aspect of the grammar allowed us to predict precisely which points in the sequence should be subject to anticipation. Results showed that participants’ pattern of anticipation could not be accounted for by “flat” statistical learning processes and was consistent with them anticipating upcoming points based on hierarchical assumptions. We also found that participants were sensitive to the structure constituency, suggesting that they organized the signal into embedded constituents. We hypothesized that the participants built this structure by merging recursively deterministic transitions.
Publisher: Elsevier BV
Date: 07-2004
Publisher: Center for Open Science
Date: 12-08-2023
Abstract: In this article, we explore the impact of presentation rate on the extraction of hierarchical structure by manipulating the duration of the Response-to-Stimulus Interval (RSI) in a Serial Reaction Time (SRT) task. Multiple hypotheses have been put forward in the literature to account for the influence of RSI duration on sequence learning in the SRT task (Frensch & Miner, 1994 Huang et al., 2017 Willingham et al., 1997). However, this question has never been addressed from the perspective of hierarchical structure extraction. We found that RSI duration affected hierarchical elaboration in a non-linear way, with participants building higher hierarchical structures with an RSI of 250 ms compared to RSIs of 1000 ms and 100 ms. This finding suggests the presence of an optimal temporal window for sequence learning in the SRT task. This U-shaped effect cannot be accounted for by any of the existing hypotheses on the influence of RSI duration on sequence learning in the SRT task. We hypothesized that this effect results from the tension between the cognitive system's limited encoding capacity and the amount of information per unit of time delivered to the system.
Publisher: IEEE
Date: 11-2015
Publisher: Frontiers Media SA
Date: 2017
Publisher: Springer Science and Business Media LLC
Date: 2002
Abstract: Aspects of syntactic complexity and syntactic repair were investigated by comparing the event-related (brain) potentials (ERPs) for sentences of different syntactic complexity to those containing a syntactic violation. Previous research had shown that both aspects of syntactic processing are reflected in a late positivity (P600). Results from the present reading experiment demonstrate, however, that although both processing aspects elicit a late positivity, they are different in distribution. The repair-related positivity preceded by a negativity displayed a centroparietal distribution, whereas the complexity-related positivity showed a frontocentral scalp distribution. These data indicate that the P600 is not a unitary phenomenon. Moreover, the distributional differences strongly suggest that different neural structures underlie the two aspects of processing, namely syntactic repair and syntactic integration difficulties, most evident when processing syntactically complex sentences.
Publisher: Center for Open Science
Date: 23-12-2022
Abstract: Converging evidence points towards a link between musical rhythm and linguistic syntax processing. Several potentially shared cognitive mechanisms and overlapping brain regions have been proposed to account for these findings. The present study explores the hypothesis that a domain-general cognitive system responsible for hierarchical structure building constitutes one such component. In two experiments, French-speaking adults listened to rhythmically regular, irregular or silent primes before completing a grammaticality judgement task on Jabberwocky sentences. Both experiments showed a priming effect only in the first three sentences after priming. Experiment 1 (block design) showed a disadvantage of the irregular condition compared to both other conditions. Experiment 2 (mixed design) showed an advantage in the regular condition compared to the irregular condition. Across the two experiments, grammaticality judgement performance correlated with rhythm discrimination. These findings provide evidence for a domain-general cognitive network responsible for hierarchical structure building in rhythm and language processing.
Publisher: Université d'Ottawa / University of Ottawa
Date: 1984
DOI: 10.20381/RUOR-13946
Publisher: Proceedings of the National Academy of Sciences
Date: 12-01-2015
Abstract: This article fills an important gap in the literature on structural changes in the brain that are induced by speaking two languages. It has been suggested that early lifelong bilingualism affects the structure of white matter (WM) of the brain and preserves its integrity in older age. Here we show that similar WM effects are also found in bilingual in iduals who learn their second language (L2) later in life and are active users of both languages. This finding presents a strong argument for the general benefits of additional language learning and the importance of language learning and use in a naturalistic environment.
Publisher: Informa UK Limited
Date: 21-10-2020
Publisher: AIP Publishing
Date: 12-2007
DOI: 10.1063/1.2795434
Abstract: We present the symbolic resonance analysis (SRA) as a viable method for addressing the problem of enhancing a weakly dominant mode in a mixture of impulse responses obtained from a nonlinear dynamical system. We demonstrate this using results from a numerical simulation with Duffing oscillators in different domains of their parameter space, and by analyzing event-related brain potentials (ERPs) from a language processing experiment in German as a representative application. In this paradigm, the averaged ERPs exhibit an N400 followed by a sentence final negativity. Contemporary sentence processing models predict a late positivity (P600) as well. We show that the SRA is able to unveil the P600 evoked by the critical stimuli as a weakly dominant mode from the covering sentence final negativity.
Publisher: Oxford University Press (OUP)
Date: 16-10-2014
Publisher: Springer Science and Business Media LLC
Date: 31-05-2008
Publisher: Cambridge University Press (CUP)
Date: 17-07-2017
DOI: 10.1017/S0142716417000212
Abstract: Artificial grammar learning is an empirical paradigm that investigates basic pattern and structural processing in different populations. It can inform how higher cognitive functions, such as language use, take place. Our study used artificial grammar learning to assess how children with Williams syndrome (WS n = 16) extract patterns in structured sequences of synthetic speech, how they compare to typically developing (TD) children ( n = 60), and how prosodic cues affect learning. The TD group was ided into a group whose nonverbal abilities were within the range of the WS group, and a group whose chronological age was within the range of the WS group. TD children relied mainly on rule-based generalization when making judgments about sequence acceptability, whereas children with WS relied on familiarity with specific stimulus combinations. The TD participants whose nonverbal abilities were similar to the WS group showed less evidence of relying on grammaticality than TD participants whose chronological age was similar to the WS group. In absence of prosodic cues, the children with WS did not demonstrate evidence of learning. Results suggest that, in WS children, the transition to rule-based processing in language does not keep pace with TD children and may be an indication of differences in neurocognitive mechanisms.
Publisher: Elsevier BV
Date: 02-2019
Publisher: Wiley
Date: 26-11-2019
Publisher: American Physical Society (APS)
Date: 11-11-2005
Publisher: Elsevier BV
Date: 07-1992
DOI: 10.1016/0093-934X(92)90024-9
Abstract: The purpose of the present study is to explore the role of an explicit expression of macrostructure in facilitating performance on a Story Arrangement Task. Subjects were presented with a series of sentences which they were required to arrange into a coherent paragraph. Half of the items were preceded by a theme sentence containing the framework or macrostructure of the paragraph, while the items without theme sentences required subjects to formulate their own macrostructure in a bottom-up fashion. Results of the study support the hypothesis that the presence of a theme sentence facilitates performance on the Story Arrangement Task for non-brain-damaged in iduals (NBDs) and left brain-damaged patients (LBDs), but not for right brain-damaged patients (RBDs). This suggests that RBDs are impaired in their ability to recognize and benefit from explicit thematic statements in narratives. Other discourse-level deficits in RBDs are discussed in the light of these findings. The performance of LBDs on such tasks is also discussed.
Publisher: Frontiers Media SA
Date: 26-07-2019
Publisher: Elsevier BV
Date: 03-2006
DOI: 10.1016/J.BANDL.2005.05.001
Abstract: In a post hoc analysis, we investigate differences in event-related potentials of two studies (Drenhaus et al., 2004, Drenhaus et al., to appear, Saddy et al., 2004a and Saddy et al., 2004b) by using the symbolic resonance analysis (Beim Graben & Kurths, 2003). The studies under discussion, examined the failure to license a negative polarity item (NPI) in German: Saddy et al. (2004a) reported an N400 component when the NPI was not accurately licensed by negation Drenhaus et al., 2004 and Drenhaus et al., to appear considered additionally the influence of constituency of the licensor in NPI constructions. A biphasic N400-P600 response was found for the two induced violations (the lack of licensor and the inaccessibility of negation in a relative clause). The symbolic resonance analysis (SRA) revealed an effect in the P600 time window for the data in Saddy et al., which was not found by using the averaging technique. The SRA of the ERPs in Drenhaus et al., showed that the P600 components are distinguishable concerning the litude and latency. It was smaller and earlier in the condition where the licensor is inaccessible, compared to the condition without negation in the string. Our findings suggest that the failure in licensing NPIs is not exclusively related to semantic integration costs (N400). The elicited P600 components reflect differences in syntactic processing. Our results confirm and replicate the effects of the traditional voltage average analysis and show that the SRA is a useful tool to reveal and pull apart ERP differences which are not evident using the traditional voltage average analysis.
Publisher: Elsevier BV
Date: 09-2008
DOI: 10.1016/J.NEURON.2008.07.011
Abstract: Numerous linguistic operations have been assigned to cortical brain areas, but the contributions of subcortical structures to human language processing are still being discussed. Using simultaneous EEG recordings directly from deep brain structures and the scalp, we show that the human thalamus systematically reacts to syntactic and semantic parameters of auditorily presented language in a temporally interleaved manner in coordination with cortical regions. In contrast, two key structures of the basal ganglia, the globus pallidus internus and the subthalamic nucleus, were not found to be engaged in these processes. We therefore propose that syntactic and semantic language analysis is primarily realized within cortico-thalamic networks, whereas a cohesive basal ganglia network is not involved in these essential operations of language analysis.
Publisher: Springer Science and Business Media LLC
Date: 23-02-2016
DOI: 10.1038/SREP21958
Abstract: Evidence shows that nutritional and environmental stress stimuli during postnatal period influence brain development and interactions between gut and brain. In this study we show that in rats, prevention of weaning from maternal milk results in depressive-like behavior, which is accompanied by changes in the gut bacteria and host metabolism. Depressive-like behavior was studied using the forced-swim test on postnatal day (PND) 25 in rats either weaned on PND 21, or left with their mother until PND 25 (non-weaned). Non-weaned rats showed an increased immobility time consistent with a depressive phenotype. Fluorescence in situ hybridization showed non-weaned rats to harbor significantly lowered Clostridium histolyticum bacterial groups but exhibit marked stress-induced increases. Metabonomic analysis of urine from these animals revealed significant differences in the metabolic profiles, with biochemical phenotypes indicative of depression in the non-weaned animals. In addition, non-weaned rats showed resistance to stress-induced modulation of oxytocin receptors in amygdala nuclei, which is indicative of passive stress-coping mechanism. We conclude that delaying weaning results in alterations to the gut microbiota and global metabolic profiles which may contribute to a depressive phenotype and raise the issue that mood disorders at early developmental ages may reflect interplay between mammalian host and resident bacteria.
Publisher: World Scientific Pub Co Pte Lt
Date: 02-2004
DOI: 10.1142/S0218127404009326
Abstract: We describe a part of the stimulus sentences of a German language processing ERP experiment using a context-free grammar and represent different processing preferences by its unambiguous partitions. The processing is modeled by deterministic pushdown automata. Using a theorem proven by Moore, we map these automata onto discrete time dynamical systems acting at the unit square, where the processing preferences are represented by a control parameter. The actual states of the automata are rectangles lying in the unit square that can be interpreted as cylinder sets in the context of symbolic dynamics theory. We show that applying a wrong processing preference to a certain input string leads to an unwanted invariant set in the parsers dynamics. Then, syntactic reanalysis and repair can be modeled by a switching of the control parameter — in analogy to phase transitions observed in brain dynamics. We argue that ERP components are indicators of these bifurcations and propose an ERP-like measure of the parsing model.
Publisher: Springer Science and Business Media LLC
Date: 05-02-2018
Publisher: Informa UK Limited
Date: 20-08-2022
Publisher: Elsevier BV
Date: 2010
Publisher: Springer Science and Business Media LLC
Date: 27-09-2016
Publisher: Public Library of Science (PLoS)
Date: 14-05-2020
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2010
End Date: 2011
Funder: Engineering and Physical Sciences Research Council
View Funded ActivityStart Date: 2011
End Date: 2013
Funder: Engineering and Physical Sciences Research Council
View Funded ActivityStart Date: 2010
End Date: 2012
Funder: Engineering and Physical Sciences Research Council
View Funded ActivityStart Date: 2008
End Date: 2011
Funder: Engineering and Physical Sciences Research Council
View Funded ActivityStart Date: 2014
End Date: 2019
Funder: European Commission
View Funded ActivityStart Date: 2015
End Date: 2017
Funder: Economic and Social Research Council
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