David W. Green's research while affiliated with University College London and other places

Publications (104)

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Using fMRI, we investigated how right temporal lobe gliomas affecting the posterior superior temporal sulcus alter neural processing observed during speech perception and production tasks. Behavioural language testing showed that three pre-operative neurosurgical patients with grade 2, grade 3 or grade 4 tumours had the same pattern of mild languag...
Preprint
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In the neurological model of language, repeating heard speech involves four left hemisphere regions: primary auditory cortex for processing sounds; Wernicke's area for processing auditory images of speech; Broca's area for processing motor images of speech; and primary motor cortex for overt speech articulation. Previous functional-MRI (fMRI) studi...
Article
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Background: Pre- and intra-operative language mapping in neurosurgery patients frequently involves an object naming task. The choice of the optimal object naming paradigm remains challenging due to lack of normative data and standardization in mapping practices. The aim of this study was to identify object naming paradigms that robustly and consist...
Article
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Controversy surrounds the interpretation of higher activation for pseudoword compared to word reading in the left precentral gyrus and pars opercularis. Specifically, does activation in these regions reflect: (1) the demands on sublexical assembly of articulatory codes, or (2) retrieval effort because the combinations of articulatory codes are unfa...
Poster
Introduction: Pre- and intra-operative language mapping in neurosurgery patients typically involves an object naming task. The choice of the optimal object naming paradigm remains challenging due to lack of normative data and standardisation in mapping practices. Objective: To identify an object naming paradigm that robustly and consistently activ...
Article
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Broca’s area in the posterior half of the left inferior frontal gyrus has traditionally been considered an important node in the speech production network. Nevertheless, recovery of speech production has been reported, to different degrees, within a few months of damage to Broca’s area. Importantly, contemporary evidence suggests that, within Broca...
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An important aim of research on bilingualism is to understand how the brain adapts to the demands of using more than one language. In this paper, we argue that pursuing such an aim entails valuing our research as a discovery process that acts on variety. Prescriptions about sample size and methodology, rightly aimed at establishing a sound basis fo...
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Specific regions of the cerebellum are activated when neurologically intact adults speak, and cerebellar damage can impair speech production early after stroke, but how the brain supports accurate speech production years after cerebellar damage remains unknown. We investigated this in patients with cerebellar lesions affecting regions that are norm...
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Establishing whether speech and language therapy after stroke has beneficial effects on speaking ability is challenging because of the need to control for multiple non-therapy factors known to influence recovery. We investigated how speaking ability at three time points post-stroke differed in patients who received varying amounts of clinical thera...
Poster
Introduction: Prior studies have shown that specific parts of both the left posterior superior temporal sulcus (LpSTS) and left temporo-parietal cortex (LTP) contribute to phonological short-term memory. As the same regions also respond during non-phonological tasks, it is unclear how LpSTS and LTP contribute to phonological short-term memory or ho...
Article
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Functional imaging studies of neurologically intact adults have demonstrated that the right posterior cerebellum is activated during verb generation, semantic processing, sentence processing, and verbal fluency. Studies of patients with cerebellar damage converge to show that the cerebellum supports sentence processing and verbal fluency. However,...
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Prior studies have reported inconsistency in the lesion sites associated with verbal short-term memory impairments. Here we asked: How many different lesion sites can account for selective impairments in verbal short-term memory that persist over time, and how consistently do these lesion sites impair verbal short-term memory? We assessed verbal sh...
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Broca’s area in the posterior half of the left inferior frontal gyrus has long been thought to be critical for speech production. The current view is that long-term speech production outcome in patients with Broca’s area damage is best explained by the combination of damage to Broca’s area and neighbouring regions including the underlying white mat...
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Understanding the aetiology of the diverse recovery patterns in bilingual aphasia is a theoretical challenge with implications for treatment. Loss of control over intact language networks provides a parsimonious starting point that can be tested using in-silico lesions. We simulated a complex recovery pattern (alternate antagonism and paradoxical t...
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This fMRI study of 24 healthy human participants investigated whether any part of the auditory cortex was more responsive to self-generated speech sounds compared to hearing another person speak. The results demonstrate a double dissociation in two different parts of the auditory cortex. In the right posterior superior temporal sulcus (RpSTS), acti...
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Acquired language disorders after stroke are strongly associated with left hemisphere damage. When language difficulties are observed in the context of right hemisphere strokes, patients are usually considered to have atypical functional anatomy. By systematically integrating behavioural and lesion data from brain damaged patients with functional M...
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Acquiring and speaking a second language increases demand on the processes of language control for bilingual as compared to monolingual speakers. Language control for bilingual speakers involves the ability to keep the two languages separated to avoid interference and to select one language or the other in a given conversational context. This abili...
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Analyses of corpus-based indices of conversational code-switching in bilingual speakers predict the occurrence of intra-sentential code-switches consistent with the joint activation of both languages. Yet most utterances contain no code-switches despite good evidence for the joint activation of both languages even in single language utterances. Var...
Article
This study investigated how sample size affects the reproducibility of findings from univariate voxel-based lesion-deficit analyses (e.g., voxel-based lesion-symptom mapping and voxel-based morphometry). Our effect of interest was the strength of the mapping between brain damage and speech articulation difficulties, as measured in terms of the prop...
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In this study, we hypothesized that if the same deficit can be caused by damage to one or another part of a distributed neural system, then voxel-based analyses might miss critical lesion sites because preservation of each site will not be consistently associated with preserved function. The first part of our investigation used voxel-based multiple...
Article
Speaking more than one language demands a language control system that allows bilinguals to correctly use the intended language adjusting for possible interference from the non-target language. Understanding how the brain orchestrates the control of language has been a major focus of neuroimaging research on bilingualism and was central to our orig...
Article
Is there a single trajectory to third-language (L3) communicative proficiency in proficient, adult bilingual speakers? Parsimony favours such a possibility but in this theoretical paper we argue that multiple trajectories will be the norm. We focus on the processes of language control. These processes mediate the initial transfer of syntactic forms...
Article
Bilingual speakers can use one of their languages in a given interactional context or switch between them when addressing different speakers during the same conversation. Depending on community usage bilingual speakers may insert single lexical forms from one language into the morphosyntactic frame of another or alternate between languages at claus...
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Structural data when allied to rich behavioural data offer an important resource for studying adaptive changes in the human brain contingent on the use of more than one language. In our commentary on the review paper by García-Pentón et al. (2015. The neuroanatomy of bilingualism: How to turn a hazy view into the full picture. Language, Cognition a...
Article
Emmorey, Giezen and Gollan (Emmorey, Giezen & Gollan) in their Key Note article review data bearing on language control in bimodal bilinguals and provoke questions critical to theoretical advance. I consider here two interrelated questions: one on multimodal synchrony and one on the control of serial order.
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Post-stroke prognoses are usually inductive, generalizing trends learned from one group of patients, whose outcomes are known, to make predictions for new patients. Research into the recovery of language function is almost exclusively focused on monolingual stroke patients, but bilingualism is the norm in many parts of the world. If bilingual langu...
Article
We used fMRI in 35 healthy participants to investigate how two neighbouring subregions in the lateral anterior temporal lobe (LATL) contribute to semantic matching and object naming. Four different levels of processing were considered: (A) recognition of the object concepts; (B) search for semantic associations related to object stimuli; (C) retrie...
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It is a timely issue to understand the impact of bilingualism upon brain structure in healthy aging and upon cognitive decline given evidence of its neuroprotective effects. Plastic changes induced by bilingualism were reported in young adults in the left inferior parietal lobule (LIPL) and its right counterpart (RIPL) (Mechelli et al., 2004). More...
Article
An important proposal in the insightful Keynote Article by Baum and Titone is that the field of bilingualism research needs to attend more closely to intersubject variability in order to understand the nature of neuroplastic changes in the brains of bilingual speakers as they age. I agree. Understanding such variability and its drivers (such as the...
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This fMRI study used a single, multi-factorial, within-subjects design to dissociate multiple linguistic and non-linguistic processing areas that are all involved in repeating back heard words. The study compared: (1) auditory to visual inputs; (2) phonological to non-phonological inputs; (3) semantic to non-semantic inputs; and (4) speech producti...
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Code-switching (CS) is central to many bilingual communities and, though linguistic and sociolinguistic research has characterised different types of code-switches (alternations, insertions, dense CS), the cognitive control processes (CPs) that mediate them are not well understood. A key issue is how during CS speakers produce the right words in th...
Article
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The aim of this paper was to investigate the neurological underpinnings of auditory-to-motor translation during auditory repetition of unfamiliar pseudowords. We tested two different hypotheses. First we used functional magnetic resonance imaging in 25 healthy subjects to determine whether a functionally defined area in the left temporo-parietal ju...
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Previous studies have investigated orthographic-to-phonological mapping during reading by comparing brain activation for (1) reading words to object naming, or (2) reading pseudowords (e.g., "phume") to words (e.g., "plume"). Here we combined both approaches to provide new insights into the underlying neural mechanisms. In fMRI data from 25 healthy...
Article
Advertisements and packaging material are frequently designed to elicit consumer inferences, some of which may be legally proscribed. This paper discusses the analysis of such inferences and the empirical resting of analytic results. By way of a case study, it reports the analysis and empirical testing of the inferences elicited by two different pa...
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During speech production, auditory processing of self-generated speech is used to adjust subsequent articulations. The current study investigated how the proposed auditory-motor interactions are manifest at the neural level in native and non-native speakers of English who were overtly naming pictures of objects and reading their written names. Data...
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This study compared the comprehension of syntactically simple with more complex sentences in Italian–English adult bilinguals and monolingual controls in the presence or absence of sentence-level interference. The task was to identify the agent of the sentence and we primarily examined the accuracy of response. The target sentence was signalled by...
Article
In a quantitative meta-analysis, using the activation likelihood estimation method, we examined the neural regions involved in bilingual cognitive control, particularly when engaging in switching between languages. The purpose of this study was to evaluate the bilingual cognitive control model originally proposed as a qualitative analysis of functi...
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Monitoring and controlling 2 language systems is fundamental to language use in bilinguals. Here, we reveal in a combined functional (event-related functional magnetic resonance imaging) and structural neuroimaging (voxel-based morphometry) study that dorsal anterior cingulate cortex (ACC), a structure tightly bound to domain-general executive cont...
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Auditory and written language in humans' comprehension necessitates attention to the message of interest and suppression of interference from distracting sources. Investigating the brain areas associated with the control of interference is challenging because it is inevitable that activation of the brain regions that control interference co-occurs...
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Using functional magnetic resonance imaging, we found that when bilinguals named pictures or read words aloud, in their native or nonnative language, activation was higher relative to monolinguals in 5 left hemisphere regions: dorsal precentral gyrus, pars triangularis, pars opercularis, superior temporal gyrus, and planum temporale. We further dem...
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This paper proposes that different experimental contexts (single or dual language contexts) permit different neural loci at which words in the target language can be selected. However, in order to develop a fuller understanding of the neural circuit mediating language control we need to consider the community context in which bilingual speakers typ...
Article
Two-way causal processes, in which a change in one factor affects a second factor which in turn affects the first, are an important feature of the natural and social world. Yet prior research (White, 1992, 1995) suggests that individuals only envisage one-way causal processes when they think of the natural world. The limiting factor may be the natu...
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Brysbaert and Duyck (2009) suggest that it is time to abandon the Revised Hierarchical Model (Kroll and Stewart, 1994) in favor of connectionist models such as BIA+ (Dijkstra and Van Heuven, 2002) that more accurately account for the recent evidence on nonselective access in bilingual word recognition. In this brief response, we first review the hi...
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Previous neuroimaging studies have suggested that developmental dyslexia has a different neural basis in Chinese and English populations because of known differences in the processing demands of the Chinese and English writing systems. Here, using functional magnetic resonance imaging, we provide the first direct statistically based investigation i...
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Background: The causal basis of the different patterns of language recovery following stroke in bilingual speakers is not well understood. Our approach distinguishes the representation of language from the mechanisms involved in its control. Previous studies have suggested that difficulties in language control can explain selective aphasia in one l...
Article
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The aim of this study was to identify regional structural differences in the brains of native speakers of a tonal language (Chinese) compared to nontonal (European) language speakers. Our expectation was that there would be differences in regions implicated in pitch perception and production. We therefore compared structural brain images in three g...
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Competing theories of short-term memory function make specific predictions about the functional anatomy of auditory short-term memory and its role in language comprehension. We analysed high-resolution structural magnetic resonance images from 210 stroke patients and employed a novel voxel based analysis to test the relationship between auditory sh...
Article
Suppressing irrelevant words is essential to successful speech production and is expected to involve general control mechanisms that reduce interference from task-unrelated processing. To investigate the neural mechanisms that suppress visual word interference, we used fMRI and a Stroop task, using a block design with an event-related analysis. Par...
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The relationship between orthography (spelling) and phonology (speech sounds) varies across alphabetic languages. Consequently, learning to read a second alphabetic language, that uses the same letters as the first, increases the phonological associations that can be linked to the same orthographic units. In subjects with English as their first lan...
Article
In a world that is becoming more multilingual, bilingual aphasia is a clinical problem with a major clinical impact. However, at present we lack causal explanations of the many features of recovery patterns and there is no consensus about the language in which the patient should receive speech therapy. Further advance requires an understanding of t...
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Category and letter fluency tasks are commonly used clinically to investigate the semantic and phonological processes central to speech production, but the neural correlates of these processes are difficult to establish with functional neuroimaging because of the relatively unconstrained nature of the tasks. This study investigated whether differen...
Article
The study of bilingual aphasia is important because we need to be able to recommend treatments consistent with a plausible estimate of the course of recovery. Yet we lack a causal account of recovery patterns. We distinguish between the neural representation of a language network and the regions involved in the control of that network. Contrary to...
Article
Understanding causal relations is fundamental to effective action but causal data can be confounded. We examined the value that participants placed on data derived from a hypothetical intervention or observation. Our materials involved a possible cause ("bottled water"), a possible confound ("food"), and a context ("a restaurant"). We supposed that...
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A key question in bilingual language production research is how bilingual individuals control the use of their two languages. The psycholinguistic literature concerning language control is unresolved. It is a matter of controversy whether (a) issues to do with control are central to understanding bilingual language processing; and (b) if they are,...
Article
This review focuses on the nature of language recovery in bilingual individuals poststroke and on the effectiveness of treatment. I consider neuropsychological and neuroimaging articles on bilingual aphasic individuals in the period 2003–2007. I examine the extent to which current evidence supports the notion that different languages are represente...